9 files changed, 2110 insertions, 0 deletions
diff --git a/src/org/apache/commons/lang3/mutable/Mutable.java b/src/org/apache/commons/lang3/mutable/Mutable.java
new file mode 100644
index 0000000..64514f0
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/Mutable.java
@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.mutable;
+
+/**
+ * Provides mutable access to a value.
+ * <p>
+ * <code>Mutable</code> is used as a generic interface to the implementations in this package.
+ * <p>
+ * A typical use case would be to enable a primitive or string to be passed to a method and allow that method to
+ * effectively change the value of the primitive/string. Another use case is to store a frequently changing primitive in
+ * a collection (for example a total in a map) without needing to create new Integer/Long wrapper objects.
+ * 
+ * @since 2.1
+ * @param <T> the type to set and get 
+ * @version $Id: Mutable.java 1153213 2011-08-02 17:35:39Z ggregory $
+ */
+public interface Mutable<T> {
+
+    /**
+     * Gets the value of this mutable.
+     * 
+     * @return the stored value
+     */
+    T getValue();
+
+    /**
+     * Sets the value of this mutable.
+     * 
+     * @param value
+     *            the value to store
+     * @throws NullPointerException
+     *             if the object is null and null is invalid
+     * @throws ClassCastException
+     *             if the type is invalid
+     */
+    void setValue(T value);
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableBoolean.java b/src/org/apache/commons/lang3/mutable/MutableBoolean.java
new file mode 100644
index 0000000..f2e0a48
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableBoolean.java
@@ -0,0 +1,193 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.mutable;
+
+import java.io.Serializable;
+
+/**
+ * A mutable <code>boolean</code> wrapper.
+ * <p>
+ * Note that as MutableBoolean does not extend Boolean, it is not treated by String.format as a Boolean parameter. 
+ * 
+ * @see Boolean
+ * @since 2.2
+ * @version $Id: MutableBoolean.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableBoolean implements Mutable<Boolean>, Serializable, Comparable<MutableBoolean> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = -4830728138360036487L;
+
+    /** The mutable value. */
+    private boolean value;
+
+    /**
+     * Constructs a new MutableBoolean with the default value of false.
+     */
+    public MutableBoolean() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableBoolean with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableBoolean(boolean value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableBoolean with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableBoolean(Boolean value) {
+        super();
+        this.value = value.booleanValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Boolean instance.
+     * 
+     * @return the value as a Boolean, never null
+     */
+    public Boolean getValue() {
+        return Boolean.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(boolean value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Boolean instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Boolean value) {
+        this.value = value.booleanValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if the current value is <code>true</code>.
+     * 
+     * @return <code>true</code> if the current value is <code>true</code>
+     * @since 2.5
+     */
+    public boolean isTrue() {
+        return value == true;
+    }
+
+    /**
+     * Checks if the current value is <code>false</code>.
+     * 
+     * @return <code>true</code> if the current value is <code>false</code>
+     * @since 2.5
+     */
+    public boolean isFalse() {
+        return value == false;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the value of this MutableBoolean as a boolean.
+     * 
+     * @return the boolean value represented by this object.
+     */
+    public boolean booleanValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Boolean.
+     *
+     * @return a Boolean instance containing the value from this mutable, never null
+     * @since 2.5
+     */
+    public Boolean toBoolean() {
+        return Boolean.valueOf(booleanValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object to the specified object. The result is <code>true</code> if and only if the argument is
+     * not <code>null</code> and is an <code>MutableBoolean</code> object that contains the same
+     * <code>boolean</code> value as this object.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof MutableBoolean) {
+            return value == ((MutableBoolean) obj).booleanValue();
+        }
+        return false;
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return the hash code returned by <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code>
+     */
+    @Override
+    public int hashCode() {
+        return value ? Boolean.TRUE.hashCode() : Boolean.FALSE.hashCode();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     *  where false is less than true
+     */
+    public int compareTo(MutableBoolean other) {
+        boolean anotherVal = other.value;
+        return value == anotherVal ? 0 : (value ? 1 : -1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableByte.java b/src/org/apache/commons/lang3/mutable/MutableByte.java
new file mode 100644
index 0000000..129d86d
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableByte.java
@@ -0,0 +1,283 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>byte</code> wrapper.
+ * <p>
+ * Note that as MutableByte does not extend Byte, it is not treated by String.format as a Byte parameter. 
+ * 
+ * @see Byte
+ * @since 2.1
+ * @version $Id: MutableByte.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableByte extends Number implements Comparable<MutableByte>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = -1585823265L;
+
+    /** The mutable value. */
+    private byte value;
+
+    /**
+     * Constructs a new MutableByte with the default value of zero.
+     */
+    public MutableByte() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableByte with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableByte(byte value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableByte with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableByte(Number value) {
+        super();
+        this.value = value.byteValue();
+    }
+
+    /**
+     * Constructs a new MutableByte parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into a byte
+     * @since 2.5
+     */
+    public MutableByte(String value) throws NumberFormatException {
+        super();
+        this.value = Byte.parseByte(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Byte instance.
+     * 
+     * @return the value as a Byte, never null
+     */
+    public Byte getValue() {
+        return Byte.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(byte value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.byteValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @since Commons Lang 2.2
+     */
+    public void add(byte operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.byteValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(byte operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.byteValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // shortValue relies on Number implementation
+    /**
+     * Returns the value of this MutableByte as a byte.
+     *
+     * @return the numeric value represented by this object after conversion to type byte.
+     */
+    @Override
+    public byte byteValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableByte as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableByte as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableByte as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableByte as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Byte.
+     *
+     * @return a Byte instance containing the value from this mutable
+     */
+    public Byte toByte() {
+        return Byte.valueOf(byteValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object to the specified object. The result is <code>true</code> if and only if the argument is
+     * not <code>null</code> and is a <code>MutableByte</code> object that contains the same <code>byte</code> value
+     * as this object.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof MutableByte) {
+            return value == ((MutableByte) obj).byteValue();
+        }
+        return false;
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableByte other) {
+        byte anotherVal = other.value;
+        return value < anotherVal ? -1 : (value == anotherVal ? 0 : 1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableDouble.java b/src/org/apache/commons/lang3/mutable/MutableDouble.java
new file mode 100644
index 0000000..f4acfa9
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableDouble.java
@@ -0,0 +1,312 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>double</code> wrapper.
+ * <p>
+ * Note that as MutableDouble does not extend Double, it is not treated by String.format as a Double parameter. 
+ * 
+ * @see Double
+ * @since 2.1
+ * @version $Id: MutableDouble.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableDouble extends Number implements Comparable<MutableDouble>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = 1587163916L;
+
+    /** The mutable value. */
+    private double value;
+
+    /**
+     * Constructs a new MutableDouble with the default value of zero.
+     */
+    public MutableDouble() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableDouble with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableDouble(double value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableDouble with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableDouble(Number value) {
+        super();
+        this.value = value.doubleValue();
+    }
+
+    /**
+     * Constructs a new MutableDouble parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into a double
+     * @since 2.5
+     */
+    public MutableDouble(String value) throws NumberFormatException {
+        super();
+        this.value = Double.parseDouble(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Double instance.
+     * 
+     * @return the value as a Double, never null
+     */
+    public Double getValue() {
+        return Double.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(double value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.doubleValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks whether the double value is the special NaN value.
+     * 
+     * @return true if NaN
+     */
+    public boolean isNaN() {
+        return Double.isNaN(value);
+    }
+
+    /**
+     * Checks whether the double value is infinite.
+     * 
+     * @return true if infinite
+     */
+    public boolean isInfinite() {
+        return Double.isInfinite(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add
+     * @since Commons Lang 2.2
+     */
+    public void add(double operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.doubleValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(double operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.doubleValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // shortValue and byteValue rely on Number implementation
+    /**
+     * Returns the value of this MutableDouble as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return (int) value;
+    }
+
+    /**
+     * Returns the value of this MutableDouble as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return (long) value;
+    }
+
+    /**
+     * Returns the value of this MutableDouble as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return (float) value;
+    }
+
+    /**
+     * Returns the value of this MutableDouble as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Double.
+     *
+     * @return a Double instance containing the value from this mutable, never null
+     */
+    public Double toDouble() {
+        return Double.valueOf(doubleValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
+     * is not <code>null</code> and is a <code>Double</code> object that represents a double that has the identical
+     * bit pattern to the bit pattern of the double represented by this object. For this purpose, two
+     * <code>double</code> values are considered to be the same if and only if the method
+     * {@link Double#doubleToLongBits(double)}returns the same long value when applied to each.
+     * <p>
+     * Note that in most cases, for two instances of class <code>Double</code>,<code>d1</code> and <code>d2</code>,
+     * the value of <code>d1.equals(d2)</code> is <code>true</code> if and only if <blockquote>
+     * 
+     * <pre>
+     *   d1.doubleValue()&nbsp;== d2.doubleValue()
+     * </pre>
+     * 
+     * </blockquote>
+     * <p>
+     * also has the value <code>true</code>. However, there are two exceptions:
+     * <ul>
+     * <li>If <code>d1</code> and <code>d2</code> both represent <code>Double.NaN</code>, then the
+     * <code>equals</code> method returns <code>true</code>, even though <code>Double.NaN==Double.NaN</code> has
+     * the value <code>false</code>.
+     * <li>If <code>d1</code> represents <code>+0.0</code> while <code>d2</code> represents <code>-0.0</code>,
+     * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though
+     * <code>+0.0==-0.0</code> has the value <code>true</code>. This allows hashtables to operate properly.
+     * </ul>
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        return (obj instanceof MutableDouble)
+            && (Double.doubleToLongBits(((MutableDouble) obj).value) == Double.doubleToLongBits(value));
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        long bits = Double.doubleToLongBits(value);
+        return (int) (bits ^ (bits >>> 32));
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableDouble other) {
+        double anotherVal = other.value;
+        return Double.compare(value, anotherVal);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableFloat.java b/src/org/apache/commons/lang3/mutable/MutableFloat.java
new file mode 100644
index 0000000..b7e0cd0
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableFloat.java
@@ -0,0 +1,313 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>float</code> wrapper.
+ * <p>
+ * Note that as MutableFloat does not extend Float, it is not treated by String.format as a Float parameter. 
+ * 
+ * @see Float
+ * @since 2.1
+ * @version $Id: MutableFloat.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableFloat extends Number implements Comparable<MutableFloat>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = 5787169186L;
+
+    /** The mutable value. */
+    private float value;
+
+    /**
+     * Constructs a new MutableFloat with the default value of zero.
+     */
+    public MutableFloat() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableFloat with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableFloat(float value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableFloat with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableFloat(Number value) {
+        super();
+        this.value = value.floatValue();
+    }
+
+    /**
+     * Constructs a new MutableFloat parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into a float
+     * @since 2.5
+     */
+    public MutableFloat(String value) throws NumberFormatException {
+        super();
+        this.value = Float.parseFloat(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Float instance.
+     * 
+     * @return the value as a Float, never null
+     */
+    public Float getValue() {
+        return Float.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(float value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.floatValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks whether the float value is the special NaN value.
+     * 
+     * @return true if NaN
+     */
+    public boolean isNaN() {
+        return Float.isNaN(value);
+    }
+
+    /**
+     * Checks whether the float value is infinite.
+     * 
+     * @return true if infinite
+     */
+    public boolean isInfinite() {
+        return Float.isInfinite(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @since Commons Lang 2.2
+     */
+    public void add(float operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.floatValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract
+     * @since Commons Lang 2.2
+     */
+    public void subtract(float operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.floatValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // shortValue and byteValue rely on Number implementation
+    /**
+     * Returns the value of this MutableFloat as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return (int) value;
+    }
+
+    /**
+     * Returns the value of this MutableFloat as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return (long) value;
+    }
+
+    /**
+     * Returns the value of this MutableFloat as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableFloat as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Float.
+     *
+     * @return a Float instance containing the value from this mutable, never null
+     */
+    public Float toFloat() {
+        return Float.valueOf(floatValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object against some other object. The result is <code>true</code> if and only if the argument is
+     * not <code>null</code> and is a <code>Float</code> object that represents a <code>float</code> that has the
+     * identical bit pattern to the bit pattern of the <code>float</code> represented by this object. For this
+     * purpose, two float values are considered to be the same if and only if the method
+     * {@link Float#floatToIntBits(float)}returns the same int value when applied to each.
+     * <p>
+     * Note that in most cases, for two instances of class <code>Float</code>,<code>f1</code> and <code>f2</code>,
+     * the value of <code>f1.equals(f2)</code> is <code>true</code> if and only if <blockquote>
+     * 
+     * <pre>
+     *   f1.floatValue() == f2.floatValue()
+     * </pre>
+     * 
+     * </blockquote>
+     * <p>
+     * also has the value <code>true</code>. However, there are two exceptions:
+     * <ul>
+     * <li>If <code>f1</code> and <code>f2</code> both represent <code>Float.NaN</code>, then the
+     * <code>equals</code> method returns <code>true</code>, even though <code>Float.NaN==Float.NaN</code> has
+     * the value <code>false</code>.
+     * <li>If <code>f1</code> represents <code>+0.0f</code> while <code>f2</code> represents <code>-0.0f</code>,
+     * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though
+     * <code>0.0f==-0.0f</code> has the value <code>true</code>.
+     * </ul>
+     * This definition allows hashtables to operate properly.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     * @see java.lang.Float#floatToIntBits(float)
+     */
+    @Override
+    public boolean equals(Object obj) {
+        return (obj instanceof MutableFloat)
+            && (Float.floatToIntBits(((MutableFloat) obj).value) == Float.floatToIntBits(value));
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return Float.floatToIntBits(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableFloat other) {
+        float anotherVal = other.value;
+        return Float.compare(value, anotherVal);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableInt.java b/src/org/apache/commons/lang3/mutable/MutableInt.java
new file mode 100644
index 0000000..eb12dad
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableInt.java
@@ -0,0 +1,273 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>int</code> wrapper.
+ * <p>
+ * Note that as MutableInt does not extend Integer, it is not treated by String.format as an Integer parameter. 
+ * 
+ * @see Integer
+ * @since 2.1
+ * @version $Id: MutableInt.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableInt extends Number implements Comparable<MutableInt>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = 512176391864L;
+
+    /** The mutable value. */
+    private int value;
+
+    /**
+     * Constructs a new MutableInt with the default value of zero.
+     */
+    public MutableInt() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableInt with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableInt(int value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableInt with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableInt(Number value) {
+        super();
+        this.value = value.intValue();
+    }
+
+    /**
+     * Constructs a new MutableInt parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into an int
+     * @since 2.5
+     */
+    public MutableInt(String value) throws NumberFormatException {
+        super();
+        this.value = Integer.parseInt(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Integer instance.
+     * 
+     * @return the value as a Integer, never null
+     */
+    public Integer getValue() {
+        return Integer.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(int value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.intValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @since Commons Lang 2.2
+     */
+    public void add(int operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.intValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(int operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.intValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // shortValue and byteValue rely on Number implementation
+    /**
+     * Returns the value of this MutableInt as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableInt as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableInt as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableInt as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Integer.
+     *
+     * @return a Integer instance containing the value from this mutable, never null
+     */
+    public Integer toInteger() {
+        return Integer.valueOf(intValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object to the specified object. The result is <code>true</code> if and only if the argument is
+     * not <code>null</code> and is a <code>MutableInt</code> object that contains the same <code>int</code> value
+     * as this object.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof MutableInt) {
+            return value == ((MutableInt) obj).intValue();
+        }
+        return false;
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableInt other) {
+        int anotherVal = other.value;
+        return value < anotherVal ? -1 : (value == anotherVal ? 0 : 1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableLong.java b/src/org/apache/commons/lang3/mutable/MutableLong.java
new file mode 100644
index 0000000..eea862d
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableLong.java
@@ -0,0 +1,273 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>long</code> wrapper.
+ * <p>
+ * Note that as MutableLong does not extend Long, it is not treated by String.format as a Long parameter. 
+ * 
+ * @see Long
+ * @since 2.1
+ * @version $Id: MutableLong.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableLong extends Number implements Comparable<MutableLong>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = 62986528375L;
+
+    /** The mutable value. */
+    private long value;
+
+    /**
+     * Constructs a new MutableLong with the default value of zero.
+     */
+    public MutableLong() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableLong with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableLong(long value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableLong with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableLong(Number value) {
+        super();
+        this.value = value.longValue();
+    }
+
+    /**
+     * Constructs a new MutableLong parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into a long
+     * @since 2.5
+     */
+    public MutableLong(String value) throws NumberFormatException {
+        super();
+        this.value = Long.parseLong(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Long instance.
+     * 
+     * @return the value as a Long, never null
+     */
+    public Long getValue() {
+        return Long.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(long value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.longValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @since Commons Lang 2.2
+     */
+    public void add(long operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.longValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(long operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.longValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // shortValue and byteValue rely on Number implementation
+    /**
+     * Returns the value of this MutableLong as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return (int) value;
+    }
+
+    /**
+     * Returns the value of this MutableLong as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableLong as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableLong as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Long.
+     *
+     * @return a Long instance containing the value from this mutable, never null
+     */
+    public Long toLong() {
+        return Long.valueOf(longValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object to the specified object. The result is <code>true</code> if and only if the argument
+     * is not <code>null</code> and is a <code>MutableLong</code> object that contains the same <code>long</code>
+     * value as this object.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof MutableLong) {
+            return value == ((MutableLong) obj).longValue();
+        }
+        return false;
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return (int) (value ^ (value >>> 32));
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableLong other) {
+        long anotherVal = other.value;
+        return value < anotherVal ? -1 : (value == anotherVal ? 0 : 1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableObject.java b/src/org/apache/commons/lang3/mutable/MutableObject.java
new file mode 100644
index 0000000..74c4f35
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableObject.java
@@ -0,0 +1,126 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.mutable;
+
+import java.io.Serializable;
+
+/**
+ * A mutable <code>Object</code> wrapper.
+ * 
+ * @since 2.1
+ * @version $Id: MutableObject.java 1088899 2011-04-05 05:31:27Z bayard $
+ */
+public class MutableObject<T> implements Mutable<T>, Serializable {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = 86241875189L;
+
+    /** The mutable value. */
+    private T value;
+
+    /**
+     * Constructs a new MutableObject with the default value of <code>null</code>.
+     */
+    public MutableObject() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableObject with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableObject(T value) {
+        super();
+        this.value = value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value.
+     * 
+     * @return the value, may be null
+     */
+    public T getValue() {
+        return this.value;
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(T value) {
+        this.value = value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * <p>
+     * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
+     * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>T</code>
+     * value as this object.
+     * </p>
+     * 
+     * @param obj  the object to compare with, <code>null</code> returns <code>false</code>
+     * @return  <code>true</code> if the objects are the same;
+     *          <code>true</code> if the objects have equivalent <code>value</code> fields;
+     *          <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (this == obj) {
+            return true;
+        }
+        if (this.getClass() == obj.getClass()) {
+            MutableObject<?> that = (MutableObject<?>) obj;
+            return this.value.equals(that.value);
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Returns the value's hash code or <code>0</code> if the value is <code>null</code>.
+     * 
+     * @return the value's hash code or <code>0</code> if the value is <code>null</code>.
+     */
+    @Override
+    public int hashCode() {
+        return value == null ? 0 : value.hashCode();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return value == null ? "null" : value.toString();
+    }
+
+}
diff --git a/src/org/apache/commons/lang3/mutable/MutableShort.java b/src/org/apache/commons/lang3/mutable/MutableShort.java
new file mode 100644
index 0000000..2dfcb00
--- /dev/null
+++ b/src/org/apache/commons/lang3/mutable/MutableShort.java
@@ -0,0 +1,283 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.mutable;
+
+/**
+ * A mutable <code>short</code> wrapper.
+ * <p>
+ * Note that as MutableShort does not extend Short, it is not treated by String.format as a Short parameter. 
+ * 
+ * @see Short
+ * @since 2.1
+ * @version $Id: MutableShort.java 1160571 2011-08-23 07:36:08Z bayard $
+ */
+public class MutableShort extends Number implements Comparable<MutableShort>, Mutable<Number> {
+
+    /**
+     * Required for serialization support.
+     * 
+     * @see java.io.Serializable
+     */
+    private static final long serialVersionUID = -2135791679L;
+
+    /** The mutable value. */
+    private short value;
+
+    /**
+     * Constructs a new MutableShort with the default value of zero.
+     */
+    public MutableShort() {
+        super();
+    }
+
+    /**
+     * Constructs a new MutableShort with the specified value.
+     * 
+     * @param value  the initial value to store
+     */
+    public MutableShort(short value) {
+        super();
+        this.value = value;
+    }
+
+    /**
+     * Constructs a new MutableShort with the specified value.
+     * 
+     * @param value  the initial value to store, not null
+     * @throws NullPointerException if the object is null
+     */
+    public MutableShort(Number value) {
+        super();
+        this.value = value.shortValue();
+    }
+
+    /**
+     * Constructs a new MutableShort parsing the given string.
+     * 
+     * @param value  the string to parse, not null
+     * @throws NumberFormatException if the string cannot be parsed into a short
+     * @since 2.5
+     */
+    public MutableShort(String value) throws NumberFormatException {
+        super();
+        this.value = Short.parseShort(value);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value as a Short instance.
+     * 
+     * @return the value as a Short, never null
+     */
+    public Short getValue() {
+        return Short.valueOf(this.value);
+    }
+
+    /**
+     * Sets the value.
+     * 
+     * @param value  the value to set
+     */
+    public void setValue(short value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the value from any Number instance.
+     * 
+     * @param value  the value to set, not null
+     * @throws NullPointerException if the object is null
+     */
+    public void setValue(Number value) {
+        this.value = value.shortValue();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Increments the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void increment() {
+        value++;
+    }
+
+    /**
+     * Decrements the value.
+     *
+     * @since Commons Lang 2.2
+     */
+    public void decrement() {
+        value--;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @since Commons Lang 2.2
+     */
+    public void add(short operand) {
+        this.value += operand;
+    }
+
+    /**
+     * Adds a value to the value of this instance.
+     * 
+     * @param operand  the value to add, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void add(Number operand) {
+        this.value += operand.shortValue();
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(short operand) {
+        this.value -= operand;
+    }
+
+    /**
+     * Subtracts a value from the value of this instance.
+     * 
+     * @param operand  the value to subtract, not null
+     * @throws NullPointerException if the object is null
+     * @since Commons Lang 2.2
+     */
+    public void subtract(Number operand) {
+        this.value -= operand.shortValue();
+    }
+
+    //-----------------------------------------------------------------------
+    // byteValue relies on Number implementation
+    /**
+     * Returns the value of this MutableShort as a short.
+     *
+     * @return the numeric value represented by this object after conversion to type short.
+     */
+    @Override
+    public short shortValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableShort as an int.
+     *
+     * @return the numeric value represented by this object after conversion to type int.
+     */
+    @Override
+    public int intValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableShort as a long.
+     *
+     * @return the numeric value represented by this object after conversion to type long.
+     */
+    @Override
+    public long longValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableShort as a float.
+     *
+     * @return the numeric value represented by this object after conversion to type float.
+     */
+    @Override
+    public float floatValue() {
+        return value;
+    }
+
+    /**
+     * Returns the value of this MutableShort as a double.
+     *
+     * @return the numeric value represented by this object after conversion to type double.
+     */
+    @Override
+    public double doubleValue() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets this mutable as an instance of Short.
+     *
+     * @return a Short instance containing the value from this mutable, never null
+     */
+    public Short toShort() {
+        return Short.valueOf(shortValue());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this object to the specified object. The result is <code>true</code> if and only if the argument
+     * is not <code>null</code> and is a <code>MutableShort</code> object that contains the same <code>short</code>
+     * value as this object.
+     * 
+     * @param obj  the object to compare with, null returns false
+     * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof MutableShort) {
+            return value == ((MutableShort) obj).shortValue();
+        }
+        return false;
+    }
+
+    /**
+     * Returns a suitable hash code for this mutable.
+     * 
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return value;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this mutable to another in ascending order.
+     * 
+     * @param other  the other mutable to compare to, not null
+     * @return negative if this is less, zero if equal, positive if greater
+     */
+    public int compareTo(MutableShort other) {
+        short anotherVal = other.value;
+        return value < anotherVal ? -1 : (value == anotherVal ? 0 : 1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns the String value of this mutable.
+     * 
+     * @return the mutable value as a string
+     */
+    @Override
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+}