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/*******************************************************************************
* Copyright 2014 See AUTHORS file.
*
* 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 com.badlogic.gdx.ai.utils;
/** A counting semaphore that does not block the thread when the requested resource is not available. No actual resource objects
* are used; the semaphore just keeps a count of the number available and acts accordingly.
*
* @author davebaol */
public interface NonBlockingSemaphore {
/** Acquires a resource if available.
*
* An invocation of this method yields exactly the same result as {@code acquire(1)}
* @return {@code true} if the resource has been acquired; {@code false} otherwise. */
public boolean acquire ();
/** Acquires the specified number of resources if they all are available.
* @return {@code true} if all the requested resources have been acquired; {@code false} otherwise. */
public boolean acquire (int resources);
/** Releases a resource returning it to this semaphore.
*
* An invocation of this method yields exactly the same result as {@code release(1)}
* @return {@code true} if the resource has been released; {@code false} otherwise. */
public boolean release ();
/** Releases the specified number of resources returning it to this semaphore.
* @return {@code true} if all the requested resources have been released; {@code false} otherwise. */
public boolean release (int resources);
/** Abstract factory for creating concrete instances of classes implementing {@link NonBlockingSemaphore}.
*
* @author davebaol */
public interface Factory {
/** Creates a semaphore with the specified name and resources.
* @param name the name of the semaphore
* @param maxResources the maximum number of resource
* @return the newly created semaphore. */
public NonBlockingSemaphore createSemaphore (String name, int maxResources);
}
}