1 files changed, 143 insertions, 0 deletions
diff --git a/simple/simple-http/src/main/java/org/simpleframework/http/message/UpdateConsumer.java b/simple/simple-http/src/main/java/org/simpleframework/http/message/UpdateConsumer.java
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+++ b/simple/simple-http/src/main/java/org/simpleframework/http/message/UpdateConsumer.java
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+/*
+ * UpdateConsumer.java February 2007
+ *
+ * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
+ *
+ * Licensed 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.simpleframework.http.message;
+
+import java.io.IOException;
+
+import org.simpleframework.transport.ByteCursor;
+
+/**
+ * The <code>UpdateConsumer</code> object is used to create a consumer
+ * that is used to consume and process large bodies. Typically a large
+ * body will be one that is delivered as part of a multipart upload
+ * or as a large form POST. The task of the large consumer is to
+ * consume all the bytes for the body, and reset the cursor after the
+ * last byte that has been send with the body. This ensures that the
+ * next character read from the cursor is the first character of a
+ * HTTP header within the pipeline.
+ *
+ * @author Niall Gallagher
+ */ 
+public abstract class UpdateConsumer implements BodyConsumer { 
+
+   /**
+    * This is an external array used to copy data between buffers.
+    */        
+   protected byte[] array;
+   
+   /**
+    * This is used to determine whether the consumer has finished.
+    */ 
+   protected boolean finished;
+  
+   /**
+    * Constructor for the <code>UpdateConsumer</code> object. This is
+    * used to create a consumer with a one kilobyte buffer used to
+    * read the contents from the cursor and transfer it to the buffer.
+    */  
+   protected UpdateConsumer() {
+      this(2048);
+   }
+   
+   /**
+    * Constructor for the <code>UpdateConsumer</code> object. This is
+    * used to create a consumer with a variable size buffer used to
+    * read the contents from the cursor and transfer it to the buffer.
+    *
+    * @param chunk this is the size of the buffer used to read bytes
+    */     
+   protected UpdateConsumer(int chunk) {
+      this.array = new byte[chunk];
+   }
+
+   /**
+    * This is used to determine whether the consumer has finished 
+    * reading. The consumer is considered finished if it has read a
+    * terminal token or if it has exhausted the stream and can not
+    * read any more. Once finished the consumed bytes can be parsed.
+    *
+    * @return true if the consumer has finished reading its content
+    */    
+   public boolean isFinished() {
+      return finished;
+   }   
+   
+   /**
+    * This method is used to consume bytes from the provided cursor.
+    * Consuming of bytes from the cursor should be done in such a
+    * way that it does not block. So typically only the number of
+    * ready bytes in the <code>ByteCursor</code> object should be 
+    * read. If there are no ready bytes then this will return.
+    *
+    * @param cursor used to consume the bytes from the HTTP pipeline
+    */    
+   public void consume(ByteCursor cursor) throws IOException {
+      int ready = cursor.ready();      
+      
+      while(ready > 0) {
+         int size = Math.min(ready, array.length);
+         int count = cursor.read(array, 0, size);        
+
+         if(count > 0) {
+            int reset = update(array, 0, count);            
+            
+            if(reset > 0) {
+               cursor.reset(reset);
+            }
+         }
+         if(finished) {
+            commit(cursor);
+        	   break;
+         }
+         ready = cursor.ready();        	 
+      }
+   } 
+   
+   /**
+    * This method can be used to commit the consumer when all data 
+    * has been consumed. It is often used to push back some data on
+    * to the cursor so that the next consumer can read valid tokens
+    * from the stream of bytes. If no commit is required then the
+    * default implementation of this will simply return quietly.
+    * 
+    * @param cursor this is the cursor used by this consumer
+    */
+   protected void commit(ByteCursor cursor) throws IOException {
+      if(!finished) {
+         throw new IOException("Consumer not finished");
+      }
+   }
+  
+   /**
+    * This is used to process the bytes that have been read from the
+    * cursor. Depending on the delimiter used this knows when the
+    * end of the body has been encountered. If the end is encountered
+    * this method must return the number of bytes overflow, and set
+    * the state of the consumer to finished.
+    *
+    * @param array this is a chunk read from the cursor
+    * @param off this is the offset within the array the chunk starts
+    * @param count this is the number of bytes within the array
+    *
+    * @return this returns the number of bytes overflow that is read
+    */    
+   protected abstract int update(byte[] array, int off, int count) throws IOException;
+}
+
+