trunk/activemq-core/src/main/java/org/apache/activemq/usage/StoreUsage.java

/**
 * 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.activemq.usage;

import org.apache.activemq.store.PersistenceAdapter;

/**
 * Used to keep track of how much of something is being used so that a
 * productive working set usage can be controlled. Main use case is manage
 * memory usage.
 * 
 * @org.apache.xbean.XBean
 * 
 */
public class StoreUsage extends Usage<StoreUsage> {

    private PersistenceAdapter store;

    public StoreUsage() {
        super(null, null, 1.0f);
    }

    public StoreUsage(String name, PersistenceAdapter store) {
        super(null, name, 1.0f);
        this.store = store;
    }

    public StoreUsage(StoreUsage parent, String name) {
        super(parent, name, 1.0f);
        this.store = parent.store;
    }

    protected long retrieveUsage() {
        if (store == null)
            return 0;
        return store.size();
    }

    public PersistenceAdapter getStore() {
        return store;
    }

    public void setStore(PersistenceAdapter store) {
        this.store = store;
        onLimitChange();
    }

    @Override
    public int getPercentUsage() {
        synchronized (usageMutex) {
            percentUsage = caclPercentUsage();
            return super.getPercentUsage();
        }
    }

    @Override
    public boolean waitForSpace(long timeout, int highWaterMark) throws InterruptedException {
        if (parent != null) {
            if (parent.waitForSpace(timeout, highWaterMark)) {
                return true;
            }
        }

        return super.waitForSpace(timeout, highWaterMark);
    }
}