[Japi-cvs] SF.net SVN: japi: [111] trunk/src/app/net/sf/japi/util/NotNullIterator.java

[<chr...@us...>]

Revision: 111
Author:   christianhujer
Date:     2006-04-26 17:25:30 -0700 (Wed, 26 Apr 2006)
ViewCVS:  http://svn.sourceforge.net/japi/?rev=111&view=rev

Log Message:
-----------
Added NotNullIterator and NotNullIterable.

Added Paths:
-----------
    trunk/src/app/net/sf/japi/util/NotNullIterator.java
Added: trunk/src/app/net/sf/japi/util/NotNullIterator.java
===================================================================
--- trunk/src/app/net/sf/japi/util/NotNullIterator.java	                        (rev 0)
+++ trunk/src/app/net/sf/japi/util/NotNullIterator.java	2006-04-27 00:25:30 UTC (rev 111)
@@ -0,0 +1,90 @@
+/*
+ * JAPI - (Yet another (hopefully) useful) Java API
+ *
+ * Copyright (C) 2006 Christian Hujer
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+package net.sf.japi.util;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+/** Iterator / Iterable decorator that skips elements which are <code>null</code>.
+ * @author <a href="mailto:ch...@it...">Christian Hujer</a>
+ */
+public class NotNullIterator<T> implements Iterator<T> {
+
+    /** The iterator to use. */
+    private final Iterator<T> iterator;
+
+    /** Prefetched next element. */
+    private T next;
+
+    /** Create a NotNullIterator over another Iterator.
+     * @param iterator
+     */
+    public NotNullIterator(final Iterator<T> iterator) {
+        this.iterator = iterator;
+        prefetchNext();
+    }
+
+    /** Prefetches the next element. */
+    private void prefetchNext() {
+        //noinspection NestedAssignment,ControlFlowStatementWithoutBraces,StatementWithEmptyBody
+        while (iterator.hasNext() && (next = iterator.next()) == null);
+    }
+
+    /** {@inheritDoc} */
+    public boolean hasNext() {
+        return next != null;
+    }
+
+    /** {@inheritDoc} */
+    public T next() {
+        if (next == null) {
+            throw new NoSuchElementException();
+        }
+        try {
+            return next;
+        } finally {
+            prefetchNext();
+        }
+    }
+
+    /** {@inheritDoc} */
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+
+    /** An Iterable adapter for NotNullIterator. */
+    public static class NotNullIterable<T> implements Iterable<T> {
+
+        /** The iterable to iterate over. */
+        private final Iterable<T> iterable;
+
+        public NotNullIterable(final Iterable<T> iterable) {
+            this.iterable = iterable;
+        }
+
+        /** {@inheritDoc} */
+        public Iterator<T> iterator() {
+            return new NotNullIterator<T>(iterable.iterator());
+        }
+
+    } // class NotNullIterable
+
+} // class NotNullIterator


Property changes on: trunk/src/app/net/sf/japi/util/NotNullIterator.java
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