- /*
- * Copyright 2000-2004 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.tools.ant.util.regexp;
-
- import org.apache.tools.ant.BuildException;
- import org.apache.tools.ant.Project;
-
- /**
- * Simple Factory Class that produces an implementation of
- * RegexpMatcher based on the system property
- * <code>ant.regexp.matcherimpl</code> and the classes
- * available.
- *
- * <p>In a more general framework this class would be abstract and
- * have a static newInstance method.</p>
- *
- */
- public class RegexpMatcherFactory {
-
- public RegexpMatcherFactory() {
- }
-
- /***
- * Create a new regular expression instance.
- */
- public RegexpMatcher newRegexpMatcher() throws BuildException {
- return newRegexpMatcher(null);
- }
-
- /***
- * Create a new regular expression instance.
- *
- * @param p Project whose ant.regexp.regexpimpl property will be used.
- */
- public RegexpMatcher newRegexpMatcher(Project p)
- throws BuildException {
- String systemDefault = null;
- if (p == null) {
- systemDefault = System.getProperty("ant.regexp.regexpimpl");
- } else {
- systemDefault = p.getProperty("ant.regexp.regexpimpl");
- }
-
- if (systemDefault != null) {
- return createInstance(systemDefault);
- // XXX should we silently catch possible exceptions and try to
- // load a different implementation?
- }
-
- try {
- testAvailability("java.util.regex.Matcher");
- return createInstance("org.apache.tools.ant.util.regexp.Jdk14RegexpMatcher");
- } catch (BuildException be) {
- // ignore
- }
-
- try {
- testAvailability("org.apache.oro.text.regex.Pattern");
- return createInstance("org.apache.tools.ant.util.regexp.JakartaOroMatcher");
- } catch (BuildException be) {
- // ignore
- }
-
- try {
- testAvailability("org.apache.regexp.RE");
- return createInstance("org.apache.tools.ant.util.regexp.JakartaRegexpMatcher");
- } catch (BuildException be) {
- // ignore
- }
-
- throw new BuildException("No supported regular expression matcher found");
- }
-
- protected RegexpMatcher createInstance(String className)
- throws BuildException {
- try {
- Class implClass = Class.forName(className);
- return (RegexpMatcher) implClass.newInstance();
- } catch (Throwable t) {
- throw new BuildException(t);
- }
- }
-
- protected void testAvailability(String className) throws BuildException {
- try {
- Class.forName(className);
- } catch (Throwable t) {
- throw new BuildException(t);
- }
- }
- }