001: /******************************************************************
002: * File: Regexp.java
003: * Created by: Dave Reynolds
004: * Created on: 10 Jan 2007
005: *
006: * (c) Copyright 2007, Hewlett-Packard Development Company, LP
007: * [See end of file]
008: * $Id: Regex.java,v 1.2 2008/01/02 12:06:20 andy_seaborne Exp $
009: *****************************************************************/package com.hp.hpl.jena.reasoner.rulesys.builtins;
010:
011: import java.util.regex.Matcher;
012: import java.util.regex.Pattern;
013:
014: import com.hp.hpl.jena.graph.Node;
015: import com.hp.hpl.jena.reasoner.rulesys.BindingEnvironment;
016: import com.hp.hpl.jena.reasoner.rulesys.BuiltinException;
017: import com.hp.hpl.jena.reasoner.rulesys.RuleContext;
018:
019: public class Regex extends BaseBuiltin {
020:
021: /**
022: * Return a name for this builtin, normally this will be the name of the
023: * functor that will be used to invoke it.
024: */
025: public String getName() {
026: return "regex";
027: }
028:
029: /**
030: * Return the expected number of arguments for this functor or 0 if the number is flexible.
031: */
032: public int getArgLength() {
033: return 0;
034: }
035:
036: /**
037: * This method is invoked when the builtin is called in a rule body.
038: * @param args the array of argument values for the builtin, this is an array
039: * of Nodes, some of which may be Node_RuleVariables.
040: * @param length the length of the argument list, may be less than the length of the args array
041: * for some rule engines
042: * @param context an execution context giving access to other relevant data
043: * @return return true if the buildin predicate is deemed to have succeeded in
044: * the current environment
045: */
046: public boolean bodyCall(Node[] args, int length, RuleContext context) {
047: if (length < 2)
048: throw new BuiltinException(this , context,
049: "Must have at least 2 arguments to " + getName());
050: String text = getString(getArg(0, args, context), context);
051: String pattern = getString(getArg(1, args, context), context);
052: Matcher m = Pattern.compile(pattern).matcher(text);
053: if (!m.matches())
054: return false;
055: if (length > 2) {
056: // bind any capture groups
057: BindingEnvironment env = context.getEnv();
058: for (int i = 0; i < Math.min(length - 2, m.groupCount()); i++) {
059: Node match = Node.createLiteral(m.group(i + 1));
060: if (!env.bind(args[i + 2], match))
061: return false;
062: }
063: }
064: return true;
065: }
066:
067: /**
068: * Return the lexical form of a literal node, error for other node types
069: */
070: protected String getString(Node n, RuleContext context) {
071: if (n.isLiteral()) {
072: return n.getLiteralLexicalForm();
073: } else {
074: throw new BuiltinException(this , context, getName()
075: + " takes only literal arguments");
076: }
077: }
078:
079: }
080:
081: /*
082: (c) Copyright 2007, 2008 Hewlett-Packard Development Company, LP
083: All rights reserved.
084:
085: Redistribution and use in source and binary forms, with or without
086: modification, are permitted provided that the following conditions
087: are met:
088:
089: 1. Redistributions of source code must retain the above copyright
090: notice, this list of conditions and the following disclaimer.
091:
092: 2. Redistributions in binary form must reproduce the above copyright
093: notice, this list of conditions and the following disclaimer in the
094: documentation and/or other materials provided with the distribution.
095:
096: 3. The name of the author may not be used to endorse or promote products
097: derived from this software without specific prior written permission.
098:
099: THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
100: IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
101: OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
102: IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
103: INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
104: NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
105: DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
106: THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
107: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
108: THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
109: */
|