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TrueZIP is a Java based Virtual File System (VFS) to enable transparent, multi-threaded read/write access to archive files (ZIP, TAR etc.) as if they were directories. Archive files may be arbitrarily nested and the nesting level is only limited by heap and file system size.

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/*
 * Copyright (C) 2005-2010 Schlichtherle IT Services
 *
 * 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 de.schlichtherle.util.regex;

import java.util.regex.*;

/**
 * A thread local {@link Matcher}.
 * This class is intended to be used in multithreaded environments for high
 * performance pattern matching.
 *
 * @see #reset(CharSequence)
 * @version $Id$
 * @since TrueZIP 6.5 (refactored from inner class in
 *        de.schlichtherle.io.DefaultArchiveDetector)
 */
public class ThreadLocalMatcher extends ThreadLocal {
    private final Pattern pattern;

    /**
     * Creates a new thread local matcher by compiling the given regex.
     *
     * @param regex The expression to be compiled.
     * @throws PatternSyntaxException If the expression's syntax is invalid.
     */
    public ThreadLocalMatcher(final String regex)
    throws PatternSyntaxException {
        this.pattern = Pattern.compile(regex);
    }

    /**
     * Creates a new thread local matcher by using the given pattern.
     *
     * @param pattern The pattern to be used.
     * @throws NullPointerException If the parameter is {@code null}.
     */
    public ThreadLocalMatcher(final Pattern pattern) {
        if (pattern == null)
            throw new NullPointerException();
        this.pattern = pattern;
    }

    protected Object initialValue() {
        return pattern.matcher(""); // NOI18N
    }

    /**
     * Resets the thread local matcher with the given character sequence and
     * returns it.
     */
    public Matcher reset(CharSequence input) {
        return ((Matcher) get()).reset(input);
    }

    /*public boolean matches() {
        return ((Matcher) tl.get()).matches();
    }

    public String group(int i) {
        return ((Matcher) tl.get()).group(i);
    }*/
}