- /* $Id: FromXmlRuleSet.java,v 1.15 2004/05/10 06:30:08 skitching Exp $
- *
- * Copyright 2001-2004 The Apache Software Foundation.
- *
- * 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 org.apache.commons.digester.xmlrules;
-
-
- import java.net.URL;
-
- import org.apache.commons.digester.Digester;
- import org.apache.commons.digester.RuleSetBase;
-
- import org.xml.sax.InputSource;
-
- /**
- * A Digester rule set where the rules come from an XML file.
- *
- * @since 1.2
- */
- public class FromXmlRuleSet extends RuleSetBase {
-
- public static final String DIGESTER_DTD_PATH = "org/apache/commons/digester/xmlrules/digester-rules.dtd";
-
- /**
- * The file containing the Digester rules, in XML.
- */
- private XMLRulesLoader rulesLoader;
-
- /**
- * The rule set for parsing the Digester rules
- */
- private DigesterRuleParser parser;
-
- /**
- * The digester for loading the rules xml.
- */
- private Digester rulesDigester;
-
- /**
- * Constructs a FromXmlRuleSet using the default DigesterRuleParser and
- * rulesDigester.
- * @param rulesXml the path to the XML document defining the Digester rules
- */
- public FromXmlRuleSet(URL rulesXml) {
- this(rulesXml, new DigesterRuleParser(), new Digester());
- }
-
- /**
- * Constructs a FromXmlRuleSet using the default DigesterRuleParser and
- * a ruleDigester for loading the rules xml.
- * @param rulesXml the path to the XML document defining the Digester rules
- * @param rulesDigester the digester to read the rules xml.
- */
- public FromXmlRuleSet(URL rulesXml, Digester rulesDigester) {
- this(rulesXml, new DigesterRuleParser(), rulesDigester);
- }
-
- /**
- * @param rulesXml the path to the XML document defining the Digester rules
- * @param parser an instance of DigesterRuleParser, for parsing the rules from XML
- */
- public FromXmlRuleSet(URL rulesXml, DigesterRuleParser parser) {
- this(rulesXml, parser, new Digester());
- }
-
- /**
- * @param rulesXml the path to the XML document defining the Digester rules
- * @param parser an instance of DigesterRuleParser, for parsing the rules from XML
- * @param rulesDigester the digester used to load the Xml rules.
- */
- public FromXmlRuleSet(URL rulesXml, DigesterRuleParser parser, Digester rulesDigester) {
- init(new URLXMLRulesLoader(rulesXml), parser, rulesDigester);
- }
-
- /**
- * Constructs a FromXmlRuleSet using the default DigesterRuleParser and
- * rulesDigester.
- * @param inputSource load the xml rules from this InputSource
- */
- public FromXmlRuleSet(InputSource inputSource) {
- this(inputSource, new DigesterRuleParser(), new Digester());
- }
-
- /**
- * Constructs a FromXmlRuleSet using the default DigesterRuleParser and
- * a ruleDigester for loading the rules xml.
- * @param inputSource load the xml rules from this InputSource
- * @param rulesDigester the digester to read the rules xml.
- */
- public FromXmlRuleSet(InputSource inputSource, Digester rulesDigester) {
- this(inputSource, new DigesterRuleParser(), rulesDigester);
- }
-
- /**
- * @param inputSource load the xml rules from this InputSource
- * @param parser an instance of DigesterRuleParser, for parsing the rules from XML
- */
- public FromXmlRuleSet(InputSource inputSource, DigesterRuleParser parser) {
- this(inputSource, parser, new Digester());
- }
-
- /**
- * @param inputSource load the xml rules from this InputSource
- * @param parser an instance of DigesterRuleParser, for parsing the rules from XML
- * @param rulesDigester the digester used to load the Xml rules.
- */
- public FromXmlRuleSet(InputSource inputSource, DigesterRuleParser parser, Digester rulesDigester) {
- init(new InputSourceXMLRulesLoader(inputSource), parser, rulesDigester);
- }
-
- /**
- * Base constructor
- */
- private void init(XMLRulesLoader rulesLoader, DigesterRuleParser parser, Digester rulesDigester) {
- this.rulesLoader = rulesLoader;
- this.parser = parser;
- this.rulesDigester = rulesDigester;
- }
-
- /**
- * Adds to the digester the set of Rule instances defined in the
- * XML file for this rule set.
- * @see org.apache.commons.digester.RuleSetBase
- */
- public void addRuleInstances(org.apache.commons.digester.Digester digester) throws XmlLoadException {
- addRuleInstances(digester, null);
- }
-
- /**
- * Adds to the digester the set of Rule instances defined in the
- * XML file for this rule set.
- * <p>
- * Note that this method doesn't have a matching one on the DigesterLoader
- * class, because it is not expected to be widely used, and DigesterLoader's
- * load method is already heavily overloaded.
- *
- * @param digester is the digester that rules will be added to.
- * @param basePath is a path that will be prefixed to every
- * pattern string defined in the xmlrules input file.
- *
- * @see org.apache.commons.digester.RuleSetBase
- * @since 1.6
- */
- public void addRuleInstances(
- org.apache.commons.digester.Digester digester,
- String basePath)
- throws XmlLoadException {
-
- URL dtdURL = getClass().getClassLoader().getResource(DIGESTER_DTD_PATH);
- if (dtdURL == null) {
- throw new XmlLoadException("Cannot find resource \"" +
- DIGESTER_DTD_PATH + "\"");
- }
- parser.setDigesterRulesDTD(dtdURL.toString());
- parser.setTarget(digester);
- parser.setBasePath(basePath);
-
- rulesDigester.addRuleSet(parser);
- rulesDigester.push(parser);
-
- rulesLoader.loadRules();
- }
-
- /**
- * Worker class encapsulates loading mechanisms.
- * Private until some reason is found to make it public.
- */
- private abstract static class XMLRulesLoader {
- /** Load rules now */
- public abstract void loadRules() throws XmlLoadException;
- }
-
- /** Loads XMLRules from an URL */
- private class URLXMLRulesLoader extends XMLRulesLoader {
- private URL url;
- public URLXMLRulesLoader(URL url) {
- this.url = url;
- }
-
- public void loadRules() throws XmlLoadException {
- try {
- rulesDigester.parse(url.openStream());
- } catch (Exception ex) {
- throw new XmlLoadException(ex);
- }
- }
- }
-
- /** Loads XMLRules from an InputSource */
- private class InputSourceXMLRulesLoader extends XMLRulesLoader {
- private InputSource inputSource;
- public InputSourceXMLRulesLoader(InputSource inputSource) {
- this.inputSource = inputSource;
- }
-
- public void loadRules() throws XmlLoadException {
- try {
- rulesDigester.parse(inputSource);
- } catch (Exception ex) {
- throw new XmlLoadException(ex);
- }
- }
- }
- }
-