init

java/org/apache/tomcat/dbcp/pool2/impl/PooledSoftReference.java

@@ -0,0 +1,98 @@
+/*
+ * 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.tomcat.dbcp.pool2.impl;
+
+import java.lang.ref.SoftReference;
+
+/**
+ * Extension of {@link DefaultPooledObject} to wrap pooled soft references.
+ *
+ * <p>This class is intended to be thread-safe.</p>
+ *
+ * @param <T> the type of the underlying object that the wrapped SoftReference
+ * refers to.
+ *
+ * @since 2.0
+ */
+public class PooledSoftReference<T> extends DefaultPooledObject<T> {
+
+    /** SoftReference wrapped by this object */
+    private volatile SoftReference<T> reference;
+
+    /**
+     * Creates a new PooledSoftReference wrapping the provided reference.
+     *
+     * @param reference SoftReference to be managed by the pool
+     */
+    public PooledSoftReference(final SoftReference<T> reference) {
+        super(null);  // Null the hard reference in the parent
+        this.reference = reference;
+    }
+
+    /**
+     * Returns the object that the wrapped SoftReference refers to.
+     * <p>
+     * Note that if the reference has been cleared, this method will return
+     * null.
+     *
+     * @return Object referred to by the SoftReference
+     */
+    @Override
+    public T getObject() {
+        return reference.get();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public String toString() {
+        final StringBuilder result = new StringBuilder();
+        result.append("Referenced Object: ");
+        result.append(getObject().toString());
+        result.append(", State: ");
+        synchronized (this) {
+            result.append(getState().toString());
+        }
+        return result.toString();
+        // TODO add other attributes
+        // TODO encapsulate state and other attribute display in parent
+    }
+
+    /**
+     * Returns the SoftReference wrapped by this object.
+     *
+     * @return underlying SoftReference
+     */
+    public synchronized SoftReference<T> getReference() {
+        return reference;
+    }
+
+    /**
+     * Sets the wrapped reference.
+     *
+     * <p>This method exists to allow a new, non-registered reference to be
+     * held by the pool to track objects that have been checked out of the pool.
+     * The actual parameter <strong>should</strong> be a reference to the same
+     * object that {@link #getObject()} returns before calling this method.</p>
+     *
+     * @param reference new reference
+     */
+    public synchronized void setReference(final SoftReference<T> reference) {
+        this.reference = reference;
+    }
+}