net.sf.common.util.SyncCtrlUtils Maven / Gradle / Ivy

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/**
 * Copyright 2011-2012 the original author or authors.
 * 
 * Licensed 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 net.sf.common.util;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Steve M. Jung
 * @since 2011. 6. 9. (version 0.0.1)
 */
public class SyncCtrlUtils {
	private static final Logger logger = LoggerFactory.getLogger(SyncCtrlUtils.class);

	public static  V wrap(String name, Closure closure) throws E {
		synchronized (get(name)) {
			try {
				return closure.execute();
			} finally {
				release(name);
			}
		}
	}

	public static  V wrap(final String name, final Map cache, final K key, final Closure closure) throws E {
		ValueUtils.assertNotNull("name", name);
		ValueUtils.assertNotNull("cache", cache);

		final boolean debug = logger.isDebugEnabled();

		if (key == null) {
			if (debug)
				logger.debug("key is null, so execute closure right away.");
			return (V) wrap(name, closure);
		}

		if (cache.containsKey(key)) {
			if (debug)
				logger.debug("get data from map cache by key: " + key);
			return cache.get(key);
		}

		return wrap(name, new Closure() {
			public V execute() throws E {
				if (cache.containsKey(key)) {
					if (debug)
						logger.debug("get data from map cache by key: " + key);
					return cache.get(key);
				}

				if (debug)
					logger.debug("get data by executing closure.");
				V value = closure.execute();
				if (value != null) {
					if (debug)
						logger.debug("put data to map cache by key: " + key);
					cache.put(key, value);
				}
				return value;
			}
		});
	}

	private static Map cache = new ConcurrentHashMap();
	public static Object get(String name) {
		ValueUtils.assertNotNull("name", name);

		final boolean debug = logger.isDebugEnabled();

		synchronized (cache) {
			Monitor monitor = null;
			try {
				if (cache.containsKey(name)) {
					monitor = cache.get(name);
					monitor.i++;
				} else {
					monitor = Monitor.newInstance();
					cache.put(name, monitor);
				}
			} finally {
				if (debug)
					logger.debug("get monitor name: " + name + ", index: " + monitor.i);
			}
			return monitor;
		}
	}
	public static void release(String name) {
		ValueUtils.assertNotNull("name", name);

		final boolean debug = logger.isDebugEnabled();

		synchronized (cache) {
			if (!cache.containsKey(name)) {
				if (debug)
					logger.debug("the monitor was not released because there was not any monitor with name: " + name);
				return;
			}

			Monitor monitor = cache.get(name);
			if (monitor.i > 0) {
				if (debug)
					logger.debug("release monitor name: " + name + ", index: " + monitor.i);
				monitor.i--;
				return;
			}

			if (debug)
				logger.debug("remove monitor name: " + name + ", index: " + monitor.i);
			cache.remove(name);
		}
	}

	static class Monitor {
		static Monitor newInstance() {
			return new Monitor();
		}
		int i = 0;
	}
}