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//               The Next Generation Logic Library                       //
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//  Copyright 2015-20xx Christoph Zengler                                //
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//  Licensed under the Apache License, Version 2.0 (the "License");      //
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package org.logicng.handlers;

/**
 * A BDD handler which cancels the build process after a given timeout.
 * @version 2.1.0
 * @since 1.6.2
 */
public class TimeoutBDDHandler extends TimeoutHandler implements BDDHandler {

    /**
     * Constructs a new timeout handler with a given timeout and a timeout type. The interpretation of the timeout depends on the timeout type:
     * 
     *     {@link TimerType#SINGLE_TIMEOUT}: The timeout is started when {@link Handler#started()} is called.
     *     Further calls to {@link Handler#started()} have no effect on the timeout.  Thus, the timeout can only be started once.
     *     {@link TimerType#RESTARTING_TIMEOUT}: The timeout is restarted when {@link Handler#started()} is called.
     *     {@link TimerType#FIXED_END}: Timeout which is interpreted as fixed point in time (in milliseconds)
     *     at which the computation should be aborted. The method {@link Handler#started()} must still be called,
     *     but does not have an effect on the timeout.
     * 
     * Note that it might take a few milliseconds more until the build process is actually canceled, since the
     * handler depends on the BDD factory's call to {@link org.logicng.knowledgecompilation.bdds.jbuddy.BDDKernel#addRef(int, BDDHandler)}.
     * @param timeout the timeout in milliseconds, its meaning is defined by the timeout type
     * @param type    the type of the timer, must not be {@code null}
     */
    public TimeoutBDDHandler(final long timeout, final TimerType type) {
        super(timeout, type);
    }

    /**
     * Constructs a new timeout handler with a given timeout and uses the timeout type {@link TimerType#SINGLE_TIMEOUT}.
     * Thus, the timeout is started when {@link Handler#started()} is called and further calls to {@link Handler#started()} have no effect on the timeout.
     * @param timeout the timeout in milliseconds
     */
    public TimeoutBDDHandler(final long timeout) {
        super(timeout);
    }

    @Override
    public boolean newRefAdded() {
        return !timeLimitExceeded();
    }
}