Java example source code file (RegExpFactory.java)

This example Java source code file (RegExpFactory.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

internalerror, jdk, jdkregexp, joni, parserexception, regexp, regexpfactory, string, unsupported

The RegExpFactory.java Java example source code

/*
 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.nashorn.internal.runtime.regexp;

import jdk.nashorn.internal.runtime.ParserException;
import jdk.nashorn.internal.runtime.options.Options;

/**
 * Factory class for regular expressions. This class creates instances of {@link JdkRegExp}.
 * An alternative factory can be installed using the {@code nashorn.regexp.impl} system property.
 */
public class RegExpFactory {

    private final static RegExpFactory instance;

    private final static String JDK  = "jdk";
    private final static String JONI = "joni";

    static {
        final String impl = Options.getStringProperty("nashorn.regexp.impl", JONI);
        switch (impl) {
            case JONI:
                instance = new JoniRegExp.Factory();
                break;
            case JDK:
                instance = new RegExpFactory();
                break;
            default:
                instance = null;
                throw new InternalError("Unsupported RegExp factory: " + impl);
        }
    }

    /**
     * Creates a Regular expression from the given {@code pattern} and {@code flags} strings.
     *
     * @param pattern RegExp pattern string
     * @param flags   RegExp flags string
     * @return new RegExp
     * @throws ParserException if flags is invalid or pattern string has syntax error.
     */
    public RegExp compile(final String pattern, final String flags) throws ParserException {
        return new JdkRegExp(pattern, flags);
    }

    /**
     * Compile a regexp with the given {@code source} and {@code flags}.
     *
     * @param pattern RegExp pattern string
     * @param flags   flag string
     * @return new RegExp
     * @throws ParserException if invalid source or flags
     */
    public static RegExp create(final String pattern, final String flags) {
        return instance.compile(pattern,  flags);
    }

    /**
     * Validate a regexp with the given {@code source} and {@code flags}.
     *
     * @param pattern RegExp pattern string
     * @param flags  flag string
     *
     * @throws ParserException if invalid source or flags
     */
    // @SuppressWarnings({"unused"})
    public static void validate(final String pattern, final String flags) throws ParserException {
        instance.compile(pattern, flags);
    }

    /**
     * Returns true if the instance uses the JDK's {@code java.util.regex} package.
     *
     * @return true if instance uses JDK regex package
     */
    public static boolean usesJavaUtilRegex() {
        return instance != null && instance.getClass() == RegExpFactory.class;
    }
}