WaitableChar.java

/*
  File: WaitableChar.java

  Originally written by Doug Lea and released into the public domain.
  This may be used for any purposes whatsoever without acknowledgment.
  Thanks for the assistance and support of Sun Microsystems Labs,
  and everyone contributing, testing, and using this code.

  History:
  Date       Who                What
  23Jun1998  dl               Create public version
*/

package com.alipay.zdal.datasource.resource.util.concurrent;

/**
 * A class useful for offloading waiting and signalling operations
 * on single char variables. 
 * <p>
 * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>]
 **/

public class WaitableChar extends SynchronizedChar {
    /** 
     * Make a new WaitableChar with the given initial value,
     * and using its own internal lock.
     **/
    public WaitableChar(char initialValue) {
        super(initialValue);
    }

    /** 
     * Make a new WaitableChar with the given initial value,
     * and using the supplied lock.
     **/
    public WaitableChar(char initialValue, Object lock) {
        super(initialValue, lock);
    }

    @Override
    public char set(char newValue) {
        synchronized (lock_) {
            lock_.notifyAll();
            return super.set(newValue);
        }
    }

    @Override
    public boolean commit(char assumedValue, char newValue) {
        synchronized (lock_) {
            boolean success = super.commit(assumedValue, newValue);
            if (success)
                lock_.notifyAll();
            return success;
        }
    }

    @Override
    public char add(char amount) {
        synchronized (lock_) {
            lock_.notifyAll();
            return super.add(amount);
        }
    }

    @Override
    public char subtract(char amount) {
        synchronized (lock_) {
            lock_.notifyAll();
            return super.subtract(amount);
        }
    }

    @Override
    public char multiply(char factor) {
        synchronized (lock_) {
            lock_.notifyAll();
            return super.multiply(factor);
        }
    }

    @Override
    public char divide(char factor) {
        synchronized (lock_) {
            lock_.notifyAll();
            return super.divide(factor);
        }
    }

    /**
     * Wait until value equals c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/

    public void whenEqual(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ == c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

    /**
     * wait until value not equal to c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/
    public void whenNotEqual(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ != c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

    /**
     * wait until value less than or equal to c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/
    public void whenLessEqual(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ <= c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

    /**
     * wait until value less than c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/
    public void whenLess(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ < c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

    /**
     * wait until value greater than or equal to c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/
    public void whenGreaterEqual(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ >= c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

    /**
     * wait until value greater than c, then run action if nonnull.
     * The action is run with the synchronization lock held.
     **/
    public void whenGreater(char c, Runnable action) throws InterruptedException {
        synchronized (lock_) {
            while (!(value_ > c))
                lock_.wait();
            if (action != null)
                action.run();
        }
    }

}