buffer lets you split a list into smaller max-size ones

1 files changed, 40 insertions, 0 deletions

diff --git a/main/src/cgeo/geocaching/utils/MiscUtils.java b/main/src/cgeo/geocaching/utils/MiscUtils.java
new file mode 100644
index 0000000..122c4eb
--- /dev/null
+++ b/main/src/cgeo/geocaching/utils/MiscUtils.java
@@ -0,0 +1,40 @@
+package cgeo.geocaching.utils;
+
+import org.apache.commons.collections4.iterators.IteratorIterable;
+import org.apache.commons.lang3.NotImplementedException;
+
+import java.util.Iterator;
+import java.util.List;
+
+final public class MiscUtils {
+
+    private MiscUtils() {}  // Do not instantiate
+
+    public static <T> Iterable<List<T>> buffer(final List<T> original, final int n) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("buffer size must be positive");
+        }
+        return new IteratorIterable<List<T>>(new Iterator<List<T>>() {
+            final int size = original.size();
+            int next = 0;
+
+            @Override
+            public boolean hasNext() {
+                return next < size;
+            }
+
+            @Override
+            public List<T> next() {
+                final List<T> result = original.subList(next, Math.min(next + n, size));
+                next += n;
+                return result;
+            }
+
+            @Override
+            public void remove() {
+                throw new NotImplementedException("remove");
+            }
+        });
+    }
+
+}