49 lines
1.1 KiB
Java
49 lines
1.1 KiB
Java
package com.ryanmichela.sshd;
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import java.util.concurrent.ExecutionException;
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/**
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* Copyright 2013 Ryan Michela
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*/
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public abstract class Waitable<T> implements Runnable {
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private enum Status {
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WAITING,
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RUNNING,
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FINISHED,
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}
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Throwable t = null;
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T value = null;
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Status status = Status.WAITING;
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public final void run() {
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synchronized (this) {
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if (status != Status.WAITING) {
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throw new IllegalStateException("Invalid state " + status);
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}
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status = Status.RUNNING;
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}
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try {
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value = evaluate();
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} catch (Throwable t) {
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this.t = t;
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} finally {
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synchronized (this) {
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status = Status.FINISHED;
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this.notifyAll();
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}
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}
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}
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protected abstract T evaluate();
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public synchronized T get() throws InterruptedException, ExecutionException {
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while (status != Status.FINISHED) {
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this.wait();
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}
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if (t != null) {
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throw new ExecutionException(t);
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}
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return value;
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}
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}
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