1 files changed, 113 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0.1-RC1/modules/common-java/src/main/java/org/apache/tuscany/sca/common/java/collection/CompoundIterator.java b/sca-java-2.x/tags/2.0.1-RC1/modules/common-java/src/main/java/org/apache/tuscany/sca/common/java/collection/CompoundIterator.java
new file mode 100644
index 0000000000..997ba89881
--- /dev/null
+++ b/sca-java-2.x/tags/2.0.1-RC1/modules/common-java/src/main/java/org/apache/tuscany/sca/common/java/collection/CompoundIterator.java
@@ -0,0 +1,113 @@
+/*
+ * 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.tuscany.sca.common.java.collection;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+public class CompoundIterator<T> implements Iterator<T> {
+    private Iterator<T>[] iterators = null;
+    private int index = 0;
+
+    public CompoundIterator(Iterator<T>... iterators) {
+        this.iterators = iterators;
+    }
+
+    @SuppressWarnings("unchecked")
+    public CompoundIterator(Collection<T>... collections) {
+        this.iterators = new Iterator[collections.length];
+        for (int i = 0; i < collections.length; i++) {
+            this.iterators[i] = collections[i].iterator();
+        }
+    }
+
+    public boolean hasNext() {
+        // if the current enum is null that means this enum is finished
+        if (currentIterator() == null) {
+            // No next enum
+            return false;
+        }
+        // If the current enum has more elements, lets go
+        return currentIterator().hasNext();
+    }
+
+    private Iterator<T> findNextIterator(boolean moveCursor) {
+        return findNextIterator(index, moveCursor);
+    }
+
+    private Iterator<T> findNextIterator(int cursor, boolean moveCursor) {
+        // next place in the array
+        int next = cursor + 1;
+        // If the cursor is still in the array
+        if (next < iterators.length) {
+
+            // If there is something in that place
+            // AND the enum is not empty
+            if (iterators[next] != null && iterators[next].hasNext()) {
+                // OK
+                if (moveCursor) {
+                    index = next;
+                }
+                return iterators[next];
+            }
+            // Try next element
+            return findNextIterator(next, moveCursor);
+        }
+        // No more elements available
+        return null;
+    }
+
+    public T next() {
+        // ask for the next element of the current enum.
+        if (currentIterator() != null) {
+            return currentIterator().next();
+        }
+
+        // no more elements in this Enum
+        // We must throw a NoSuchElementException
+        throw new NoSuchElementException("No more elements");
+    }
+
+    public void remove() {
+        // ask for the next element of the current enum.
+        if (currentIterator() != null) {
+            currentIterator().remove();
+        }
+
+        // no more elements in this Enum
+        // We must throw a NoSuchElementException
+        throw new NoSuchElementException("No more elements");
+    }
+    
+    private Iterator<T> currentIterator() {
+        if (iterators != null) {
+            if (index < iterators.length) {
+                Iterator<T> e = iterators[index];
+                if (e == null || !e.hasNext()) {
+                    // the current enum is null or empty
+                    // we probably want to switch to the next one
+                    e = findNextIterator(true);
+                }
+                return e;
+            }
+        }
+        return null;
+    }
+}