InterruptibleCharSequence.java

/*
 *  This file is part of the Heritrix web crawler (crawler.archive.org).
 *
 *  Licensed to the Internet Archive (IA) by one or more individual 
 *  contributors. 
 *
 *  The IA licenses this file to You 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.archive.util;

/**
 * CharSequence that noticed thread interrupts -- as might be necessary 
 * to recover from a loose regex on unexpected challenging input. 
 * 
 * @author gojomo
 */
public class InterruptibleCharSequence implements CharSequence {
    protected CharSequence inner;
    // public long counter = 0; 
    
    public InterruptibleCharSequence(CharSequence inner) {
        super();
        this.inner = inner;
    }

    public char charAt(int index) {
        if (Thread.interrupted()) { // clears flag if set
            throw new RuntimeException(new InterruptedException());
        }
        // counter++;
        return inner.charAt(index);
    }

    public int length() {
        return inner.length();
    }

    public CharSequence subSequence(int start, int end) {
        return new InterruptibleCharSequence(inner.subSequence(start, end));
    }
    
    @Override
    public String toString() {
        return inner.toString();
    }
}