svn commit: r1565601 - /jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java

[al...@apache.org]

Author: alexparvulescu
Date: Fri Feb  7 09:56:17 2014
New Revision: 1565601

URL: http://svn.apache.org/r1565601
Log:
OAK-1401 Move AbstractLazyIterator to o.a.j.commons.iterator (jackrabbit/jcr-commons)
 - copied class to jackrabbit/jcr-commons


Added:
    jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java   (with props)

Added: jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java
URL: http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java?rev=1565601&view=auto
==============================================================================
--- jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java (added)
+++ jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java Fri Feb  7 09:56:17 2014
@@ -0,0 +1,68 @@
+/*
+ * 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.jackrabbit.commons.iterator;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+/**
+ * {@code AbstractLazyIterator} provides basic iteration methods for a lazy loading iterator that does not support
+ * remove. Implementing classes only need to implement the {@link #getNext()} method which must return the next item
+ * in the iteration or {@code null} if the iteration as reached its end.
+ */
+public abstract class AbstractLazyIterator<T> implements Iterator<T> {
+
+    private boolean fetchNext = true;
+
+    private T next;
+
+    protected AbstractLazyIterator() {
+    }
+
+    @Override
+    public boolean hasNext() {
+        if (fetchNext) {
+            next = getNext();
+            fetchNext = false;
+        }
+        return next != null;
+    }
+
+    @Override
+    public T next() {
+        if (fetchNext) {
+            next = getNext();
+        } else {
+            fetchNext = true;
+        }
+        if (next == null) {
+            throw new NoSuchElementException();
+        }
+        return next;
+    }
+
+    /**
+     * Returns the next element of this iteration or {@code null} if the iteration has finished.
+     * @return the next element.
+     */
+    abstract protected T getNext();
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+}
\ No newline at end of file

Propchange: jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java
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Propchange: jackrabbit/trunk/jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/iterator/AbstractLazyIterator.java
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