Author: reto
Date: Thu May 27 20:33:45 2010
New Revision: 948973
URL: http://svn.apache.org/viewvc?rev=948973&view=rev
Log:
added IteratorMerger that flattens an Iterator of Iterators to an Iterator
Added:
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.utils/src/main/java/org/apache/clerezza/utils/IteratorMerger.java
Added:
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.utils/src/main/java/org/apache/clerezza/utils/IteratorMerger.java
URL:
http://svn.apache.org/viewvc/incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.utils/src/main/java/org/apache/clerezza/utils/IteratorMerger.java?rev=948973&view=auto
==============================================================================
---
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.utils/src/main/java/org/apache/clerezza/utils/IteratorMerger.java
(added)
+++
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.utils/src/main/java/org/apache/clerezza/utils/IteratorMerger.java
Thu May 27 20:33:45 2010
@@ -0,0 +1,71 @@
+/*
+ * 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.clerezza.utils;
+
+import java.util.Iterator;
+
+/**
+ * Flattens an Iterator of Iterators to an Iterator
+ *
+ * @author reto
+ */
+public class IteratorMerger<T> implements Iterator<T> {
+
+ private final Iterator<Iterator<T>> baseIterators;
+ private Iterator<T> current;
+
+ /**
+ * constructs an iterator that will return the elements of the
baseIterators
+ *
+ * @param baseIterators
+ */
+ public IteratorMerger(Iterator<Iterator<T>> baseIterators) {
+ this.baseIterators = baseIterators;
+ current = baseIterators.next();
+ }
+
+ private void updateCurrentIfNeeded() {
+ while (!current.hasNext()) {
+ if (baseIterators.hasNext()) {
+ current = baseIterators.next();
+ } else {
+ return;
+ }
+ }
+ }
+
+ @Override
+ public boolean hasNext() {
+ updateCurrentIfNeeded();
+ return current.hasNext();
+ }
+
+ @Override
+ public T next() {
+ updateCurrentIfNeeded();
+ return current.next();
+ }
+
+ @Override
+ public void remove() {
+ current.remove();
+ }
+
+}
