001    /*
002     * Copyright (c) 2006 Henri Sivonen
003     *
004     * Permission is hereby granted, free of charge, to any person obtaining a 
005     * copy of this software and associated documentation files (the "Software"), 
006     * to deal in the Software without restriction, including without limitation 
007     * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
008     * and/or sell copies of the Software, and to permit persons to whom the 
009     * Software is furnished to do so, subject to the following conditions:
010     *
011     * The above copyright notice and this permission notice shall be included in 
012     * all copies or substantial portions of the Software.
013     *
014     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
015     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
016     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
017     * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
018     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
019     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
020     * DEALINGS IN THE SOFTWARE.
021     */
022    
023    package org.whattf.datatype;
024    
025    import org.mozilla.javascript.EcmaError;
026    import org.mozilla.javascript.regexp.RegExpImpl;
027    import org.relaxng.datatype.DatatypeException;
028    
029    /**
030     * This datatype shall accept the strings that are allowed as the value of the Web Forms 2.0 
031     * <a href="http://whatwg.org/specs/web-forms/current-work/#pattern"><code>pattern</code></a> 
032     * attribute.
033     * @version $Id: Pattern.java 121 2006-11-18 11:51:44Z hsivonen $
034     * @author hsivonen
035     */
036    public final class Pattern extends AbstractDatatype {
037    
038        /**
039         * The singleton instance.
040         */
041        public static final Pattern THE_INSTANCE = new Pattern();
042    
043        /**
044         * Package-private constructor
045         */
046        private Pattern() {
047            super();
048        }
049    
050        /**
051         * Checks that the value compiles as an anchored JavaScript regular expression.
052         * @param literal the value
053         * @param context ignored
054         * @throws DatatypeException if the value isn't valid
055         * @see org.relaxng.datatype.Datatype#checkValid(java.lang.String, org.relaxng.datatype.ValidationContext)
056         */
057        public void checkValid(CharSequence literal)
058                throws DatatypeException {
059            // TODO find out what kind of thread concurrency guarantees are made
060            RegExpImpl rei = new RegExpImpl();
061            String anchoredRegex = "^(?:" + literal + ")$";
062            try {
063                rei.compileRegExp(null, anchoredRegex, "");
064            } catch (EcmaError ee) {
065                throw new DatatypeException("Bad pattern: " + ee.getErrorMessage());
066            }
067        }
068    }