1 files changed, 102 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0.1-RC1/modules/common-xml/src/main/java/org/apache/tuscany/sca/common/xml/dom/ParserPool.java b/sca-java-2.x/tags/2.0.1-RC1/modules/common-xml/src/main/java/org/apache/tuscany/sca/common/xml/dom/ParserPool.java
new file mode 100644
index 0000000000..e8187d481d
--- /dev/null
+++ b/sca-java-2.x/tags/2.0.1-RC1/modules/common-xml/src/main/java/org/apache/tuscany/sca/common/xml/dom/ParserPool.java
@@ -0,0 +1,102 @@
+/*
+ * 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.xml.dom;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+
+public abstract class ParserPool<V> {
+    private int maxSize;
+    private Map<V, Boolean> objects;
+
+    public ParserPool() {
+        this(32, 0);
+    }
+
+    public ParserPool(int maxSize, int initialSize) {
+        super();
+        this.maxSize = maxSize;
+        this.objects = new IdentityHashMap<V, Boolean>(maxSize);
+        for (int i = 0; i < Math.min(initialSize, maxSize); i++) {
+            objects.put(newInstance(), Boolean.FALSE);
+        }
+    }
+
+    public synchronized V borrowFromPool() {
+        while (true) {
+            for (Map.Entry<V, Boolean> e : objects.entrySet()) {
+                if (Boolean.FALSE.equals(e.getValue())) {
+                    // setValue fails on some Harmony based JDKs, see https://issues.apache.org/jira/browse/HARMONY-6419
+                    //e.setValue(Boolean.TRUE); // in use
+                    V key = e.getKey();
+                    objects.put(key, Boolean.TRUE); // in use
+                    return key;
+                }
+            }
+            if (objects.size() < maxSize) {
+                V obj = newInstance();
+                objects.put(obj, Boolean.TRUE);
+                return obj;
+            }
+            try {
+                wait();
+            } catch (InterruptedException e1) {
+                throw new IllegalStateException(e1);
+            }
+        }
+    }
+
+    public synchronized void returnToPool(V obj) {
+        resetInstance(obj);
+        objects.put(obj, Boolean.FALSE);
+        notifyAll();
+    }
+
+    public synchronized void clear() {
+        objects.clear();
+    }
+
+    public synchronized int inUse() {
+        int size = 0;
+        for (Map.Entry<V, Boolean> e : objects.entrySet()) {
+            if (Boolean.TRUE.equals(e.getValue())) {
+                size++;
+            }
+        }
+        return size;
+    }
+
+    /**
+     * Create a new instance
+     * @return
+     */
+    protected abstract V newInstance();
+
+    /**
+     * Reset the instance before returning to the pool
+     * @param obj
+     */
+    protected abstract void resetInstance(V obj);
+
+    // Expose it for testing purpose
+    public Map<V, Boolean> getObjects() {
+        return objects;
+    }
+}