A convenience class that lets you iterator over a non-sorted collection

or iterator in a sorted manner.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1358 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/util/SortedIterator.java

@@ -0,0 +1,78 @@
+//
+// $Id: SortedIterator.java,v 1.1 2003/12/17 21:58:06 ray Exp $
+
+package com.samskivert.util;
+
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Iterator;
+
+/**
+ * An iterator that returns the elements from another iterator into
+ * some sorted order.
+ */
+public class SortedIterator implements Iterator
+{
+    /**
+     * Construct a sorted iterator that iterates through the specified
+     * elements in natural order.
+     */
+    public SortedIterator (Iterator itr)
+    {
+        this(itr, Comparators.COMPARABLE);
+    }
+
+    /**
+     * Construct a sorted iterator that iterates through the specified
+     * elements in the order according to the specified comparator.
+     */
+    public SortedIterator (Iterator itr, Comparator comparator)
+    {
+        SortableArrayList list = new SortableArrayList();
+        while (itr.hasNext()) {
+            list.insertSorted(itr.next(), comparator);
+        }
+        _itr = list.iterator();
+    }
+
+    /**
+     * Construct a sorted iterator that iterates through the specified
+     * collection in natural order.
+     */
+    public SortedIterator (Collection c)
+    {
+        this(c.iterator());
+    }
+
+    /**
+     * Construct a sorted iterator that iterates through the specified
+     * collection in the order according to the specified comparator.
+     */
+    public SortedIterator (Collection c, Comparator comparator)
+    {
+        this(c.iterator(), comparator);
+    }
+
+    // documentation inherited from interface Iterator
+    public boolean hasNext ()
+    {
+        return _itr.hasNext();
+    }
+
+    // documentation inherited from interface Iterator
+    public Object next ()
+    {
+        return _itr.next();
+    }
+
+    // documentation inherited from interface Iterator
+    public void remove ()
+    {
+        // sadly, we cannot
+        throw new UnsupportedOperationException(
+            "Cannot remove from a SortedIterator");
+    }
+
+    /** The iterator we are a wrapper around. */
+    protected Iterator _itr;
+}