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/*******************************************************************************
* ============LICENSE_START====================================================
* * org.onap.aaf
* * ===========================================================================
* * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
* * ===========================================================================
* * 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.
* * ============LICENSE_END====================================================
* *
* * ECOMP is a trademark and service mark of AT&T Intellectual Property.
* *
******************************************************************************/
package org.onap.aaf.inno.env.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.onap.aaf.inno.env.APIException;
import org.onap.aaf.inno.env.Creatable;
import org.onap.aaf.inno.env.Env;
import org.onap.aaf.inno.env.LifeCycle;
/**
* <h1>RefreshableThreadObject</h1>
* This is a ThreadLocal like implementation, but it responds to
* the {@link LifeCycle} mechanism for configuration refreshes, and
* implements {@link Creatable} (for use in destroy, etc).<p>
*
* In addition to the Thread instance semantics, it compares when the object
* was created versus the last "refresh(env)" call when getting, for the
* thread, and if necessary to replace the created object, destroying the
* previous.<p>
*
* In most cases, it's better to use the new "Pool" mechanism, as it deals with
* gaining and returning resources on an as needed basis. This, however, remains
* in the cases where specific Objects need to be retained to specific Threads.<p>
*
* There is no way to do this kind of specialized behavior in ThreadLocal.
*
*
* @param <T>
*/
public class RefreshableThreadObject<T extends Creatable<T>> {
private Map<Thread,T> objs;
private long refreshed;
private Constructor<T> cnst;
/**
* The passed in class <b>must</b> implement the constructor
* <pre>
* public MyClass(Env env) {
* ...
* }
* </pre>
* @param clss
* @throws APIException
*/
public RefreshableThreadObject(Class<T> clss) throws APIException {
objs = Collections.synchronizedMap(new HashMap<Thread,T>());
try {
cnst = clss.getConstructor(new Class[]{Env.class} );
} catch (Exception e) {
throw new APIException(e);
}
}
/**
* Get the "T" class from the current thread
*
* @param env
* @return T
* @throws APIException
*/
public T get(Env env) throws APIException {
Thread t = Thread.currentThread();
T obj = objs.get(t);
if(obj==null || refreshed>obj.created()) {
try {
obj = cnst.newInstance(new Object[]{env});
} catch (InvocationTargetException e) {
throw new APIException(e.getTargetException());
} catch (Exception e) {
throw new APIException(e);
}
T destroyMe = objs.put(t,obj);
if(destroyMe!=null) {
destroyMe.destroy(env);
}
}
return obj;
}
/**
* Mark the timestamp of refreshed.
*
* @param env
*/
public void refresh(Env env) {
refreshed = System.currentTimeMillis();
}
/**
* Remove the object from the Thread instances
* @param env
*/
public void remove(Env env) {
T obj = objs.remove(Thread.currentThread());
if(obj!=null)
obj.destroy(env);
}
}
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