Helper NonescalableRead

Jan Burse, created Jun 02. 2019
package matula.util.misc;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
/**
* <p>This class provides a unslotted and non-escalable read lock object.</p>
* <p/>
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies GmbH.
* <p/>
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies GmbH. If the company was not the originator of some
* excerpts, XLOG Technologies GmbH has at least obtained the right to
* reproduce, change and translate the information.
* <p/>
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* <p/>
* Restrictions
* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
* <p/>
* Trademarks
* Jekejeke is a registered trademark of XLOG Technologies GmbH.
*/
public final class NonescalableRead implements Lock {
private final Nonescalable parent;
/**
* <p>Create a read lock.</p>
*
* @param p The read write state.
*/
NonescalableRead(Nonescalable p) {
parent = p;
}
/**
* <p>Acquire the read lock.</p>
* <p>Blocks if read lock is already held.</p>
*/
public void lock() {
throw new IllegalArgumentException("not supported");
}
/**
* <p>Acquire the read lock.</p>
* <p>Blocks if read lock is already held.</p>
*
* @throws InterruptedException If the request was cancelled.
*/
public void lockInterruptibly() throws InterruptedException {
parent.acquire(1);
}
/**
* <p>Attempt the read lock.</p>
* <p>Fails if read lock is already held.</p>
*
* @return True if read lock was acquired, or false otherwise.
*/
public boolean tryLock() {
return parent.tryAcquire(1);
}
/**
* <p>Acquire the read lock or time-out.</p>
* <p>Blocks if read lock is already held and while not time-out.</p>
*
* @param sleep The time-out.
* @param tu The time unit.
* @return True if lock was acquired, or false otherwise.
* @throws InterruptedException If the request was cancelled.
*/
public boolean tryLock(long sleep, TimeUnit tu)
throws InterruptedException {
return parent.tryAcquire(1, sleep, tu);
}
/**
* <p>Retrieve a condition.</p>
*
* @return The condition.
*/
public Condition newCondition() {
throw new IllegalArgumentException("not supported");
}
/**
* <p>Release a read lock.</p>
*/
public void unlock() throws IllegalStateException {
parent.release(1);
}
}

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