/*
* 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
*
* https://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;
}
/**
* Gets the object that the wrapped SoftReference refers to.
* <p>
* Note that if the reference has been cleared, this method will return
* null.
* </p>
*
* @return Object referred to by the SoftReference
*/
@Override
public T getObject() {
return reference.get();
}
/**
* Gets 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;
}
@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
}
}