EarlyReturn.java Source code

Introduction

Here is the source code for EarlyReturn.java

Source

public class EarlyReturn extends Object {
    private volatile int value;

    public EarlyReturn(int v) {
        value = v;
    }

    public synchronized void setValue(int v) {
        if (value != v) {
            value = v;
            notifyAll();
        }
    }

    public synchronized boolean waitUntilAtLeast(int minValue, long msTimeout) throws InterruptedException {

        System.out.println("value=" + value + ",minValue=" + minValue);

        long endTime = System.currentTimeMillis() + msTimeout;
        long msRemaining = msTimeout;

        while ((value < minValue) && (msRemaining > 0L)) {
            System.out.println("about to: wait(" + msRemaining + ")");
            wait(msRemaining);
            msRemaining = endTime - System.currentTimeMillis();
            System.out.println("back from wait(), new msRemaining=" + msRemaining);
        }

        System.out.println("leaving waitUntilAtLeast() - " + "value=" + value + ",minValue=" + minValue);

        // May have timed out, or may have met value,
        return (value >= minValue);
    }

    public static void main(String[] args) {
        try {
            final EarlyReturn er = new EarlyReturn(0);

            Runnable r = new Runnable() {
                public void run() {
                    try {
                        Thread.sleep(1500);
                        er.setValue(2);
                        Thread.sleep(500);
                        er.setValue(3);
                        Thread.sleep(500);
                        er.setValue(4);
                    } catch (Exception x) {
                        x.printStackTrace();
                    }
                }
            };

            Thread t = new Thread(r);
            t.start();

            System.out.println("waitUntilAtLeast(5, 3000)");
            long startTime = System.currentTimeMillis();
            boolean retVal = er.waitUntilAtLeast(5, 3000);
            long elapsedTime = System.currentTimeMillis() - startTime;

            System.out.println(elapsedTime + " ms, retVal=" + retVal);
        } catch (InterruptedException ix) {
            ix.printStackTrace();
        }
    }
}