CharSequenceFuture.java

/* 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package org.esigate.parser.future;

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 * This class is a simple wrapper on a CharSequence.
 * <p>
 * This Future object already has it result and does not use any background Thread and simply return the
 * {@link CharSequence} provided at the construction time.
 * 
 * @author Nicolas Richeton
 * 
 */
public class CharSequenceFuture implements Future<CharSequence> {
    private final CharSequence seq;

    /**
     * Create a new Future object which will return the {@link CharSequence} provided as parameter.
     * 
     * @param charSequence
     *            the sequence which will be returned on {@link #get()}
     */
    public CharSequenceFuture(CharSequence charSequence) {
        this.seq = charSequence;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.concurrent.Future#isDone()
     */
    @Override
    public boolean isDone() {
        // This future is already done per implementation.
        return true;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.concurrent.Future#isCancelled()
     */
    @Override
    public boolean isCancelled() {
        // Cannot ever been cancelled
        return false;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.concurrent.Future#get(long, java.util.concurrent.TimeUnit)
     */
    @Override
    public CharSequence get(long timeout, TimeUnit unit) {
        // Get will never block, just use the default implementation.
        return get();
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.concurrent.Future#get()
     */
    @Override
    public CharSequence get() {
        // Return the wrapped CharSequence.
        return this.seq;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.concurrent.Future#cancel(boolean)
     */
    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
        // Cannot be cancelled.
        return false;
    }
}