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/*
* Copyright (c) 2005, Eric Crahen
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is furnished
* to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#ifndef __ZTWAITABLE_H__
#define __ZTWAITABLE_H__
#include "zthread/Exceptions.h"
namespace ZThread {
/**
* @class Waitable
*
* @author Eric Crahen <http://www.code-foo.com>
* @date <2003-07-16T22:16:41-0400>
* @version 2.3.0
*
* The Waitable interface defines a common method of adding generic <i>wait</i> semantics
* to a class.
*
* <b>Waiting</b>
*
* An object implementing the Waitable interface externalizes a mechanism for testing
* some internal condition. Another object may <i>wait()</i>s for a Waitable object;
* in doing so, it wait()s for that condition to become true by blocking the caller
* while the condition is false.
*
* For example, a Condition is Waitable object that extends <i>wait</i> semantics
* so that wait()ing means a thread is blocked until some external stimulus
* specifically performs an operation on the Condition to make its internal condition true.
* (serialization aside)
*
* A Barrier extends <i>wait</i> semantics so that wait()ing mean waiting for other
* waiters, and may include automatically resetting the condition once a wait is complete.
*
* @see Condition
* @see Barrier
* @see Executor
*/
class Waitable {
public:
//! Destroy a Waitable object.
virtual ~Waitable() {}
/**
* Waiting on an object will generally cause the calling thread to be blocked
* for some indefinite period of time. The thread executing will not proceed
* any further until the Waitable object releases it unless or an exception
* is thrown.
*/
virtual void wait() = 0;
/**
* Waiting on an object will generally cause the calling thread to be blocked
* for some indefinite period of time. The thread executing will not proceed
* any further until the Waitable object releases it unless or an exception
* is thrown.
*
* @param timeout maximum amount of time, in milliseconds, to spend waiting.
*
* @return
* - <em>true</em> if the set of tasks being wait for complete before
* <i>timeout</i> milliseconds elapse.
* - <em>false</em> othewise.
*/
virtual bool wait(unsigned long timeout) = 0;
}; /* Waitable */
} // namespace ZThread
#endif // __ZTWAITABLE_H__
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