1 /* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.nashorn.internal.runtime.regexp; 27 28 import java.util.Collections; 29 import java.util.Map; 30 import java.util.WeakHashMap; 31 import jdk.nashorn.internal.runtime.ParserException; 32 import jdk.nashorn.internal.runtime.options.Options; 33 34 /** 35 * Factory class for regular expressions. This class creates instances of {@link JdkRegExp}. 36 * An alternative factory can be installed using the {@code nashorn.regexp.impl} system property. 37 */ 38 public class RegExpFactory { 39 40 private final static RegExpFactory instance; 41 42 private final static String JDK = "jdk"; 43 private final static String JONI = "joni"; 44 45 /** Weak cache of already validated regexps - when reparsing, we don't, for example 46 * need to recompile (reverify) all regexps that have previously been parsed by this 47 * RegExpFactory in a previous compilation. This saves significant time in e.g. avatar 48 * startup 49 */ 50 private static final Map<String, RegExp> REGEXP_CACHE = 51 Collections.synchronizedMap(new WeakHashMap<String, RegExp>()); 52 53 static { 54 final String impl = Options.getStringProperty("nashorn.regexp.impl", JONI); 55 switch (impl) { 56 case JONI: 57 instance = new JoniRegExp.Factory(); 58 break; 59 case JDK: 60 instance = new RegExpFactory(); 61 break; 62 default: 63 instance = null; 64 throw new InternalError("Unsupported RegExp factory: " + impl); 65 } 66 } 67 68 /** 69 * Creates a Regular expression from the given {@code pattern} and {@code flags} strings. 70 * 71 * @param pattern RegExp pattern string 72 * @param flags RegExp flags string 73 * @return new RegExp 74 * @throws ParserException if flags is invalid or pattern string has syntax error. 75 */ 76 public RegExp compile(final String pattern, final String flags) throws ParserException { 77 return new JdkRegExp(pattern, flags); 78 } 79 80 /** 81 * Compile a regexp with the given {@code source} and {@code flags}. 82 * 83 * @param pattern RegExp pattern string 84 * @param flags flag string 85 * @return new RegExp 86 * @throws ParserException if invalid source or flags 87 */ 88 public static RegExp create(final String pattern, final String flags) { 89 final String key = pattern + "/" + flags; 90 RegExp regexp = REGEXP_CACHE.get(key); 91 if (regexp == null) { 92 regexp = instance.compile(pattern, flags); 93 REGEXP_CACHE.put(key, regexp); 94 } 95 return regexp; 96 } 97 98 /** 99 * Validate a regexp with the given {@code source} and {@code flags}. 100 * 101 * @param pattern RegExp pattern string 102 * @param flags flag string 103 * 104 * @throws ParserException if invalid source or flags 105 */ 106 public static void validate(final String pattern, final String flags) throws ParserException { 107 create(pattern, flags); 108 } 109 110 /** 111 * Returns true if the instance uses the JDK's {@code java.util.regex} package. 112 * 113 * @return true if instance uses JDK regex package 114 */ 115 public static boolean usesJavaUtilRegex() { 116 return instance != null && instance.getClass() == RegExpFactory.class; 117 } 118 }