| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 |
| * |
| * https://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.MagicNames; |
| import org.apache.tools.ant.Project; |
| import org.apache.tools.ant.util.ClasspathUtils; |
| |
| /** |
| * Simple Factory Class that produces an implementation of RegexpMatcher based on the system |
| * property <code>ant.regexp.regexpimpl</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 { |
| |
| /*** |
| * Create a new regular expression instance. |
| * @return the matcher |
| * @throws BuildException on error |
| */ |
| 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. |
| * @return the matcher |
| * @throws BuildException on error |
| */ |
| public RegexpMatcher newRegexpMatcher(Project p) throws BuildException { |
| String systemDefault; |
| if (p == null) { |
| systemDefault = System.getProperty(MagicNames.REGEXP_IMPL); |
| } else { |
| systemDefault = p.getProperty(MagicNames.REGEXP_IMPL); |
| } |
| |
| if (systemDefault != null) { |
| return createInstance(systemDefault); |
| // TODO should we silently catch possible exceptions and try to |
| // load a different implementation? |
| } |
| |
| return new Jdk14RegexpMatcher(); |
| } |
| |
| /** |
| * Create an instance of a matcher from a classname. |
| * |
| * @param className a <code>String</code> value |
| * @return a <code>RegexpMatcher</code> value |
| * @exception BuildException if an error occurs |
| */ |
| protected RegexpMatcher createInstance(String className) throws BuildException { |
| return ClasspathUtils.newInstance(className, |
| RegexpMatcherFactory.class.getClassLoader(), RegexpMatcher.class); |
| } |
| |
| /** |
| * Test if a particular class is available to be used. |
| * |
| * @param className a <code>String</code> value |
| * @exception BuildException if an error occurs |
| */ |
| protected void testAvailability(String className) throws BuildException { |
| try { |
| Class.forName(className); |
| } catch (Throwable t) { |
| throw new BuildException(t); |
| } |
| } |
| |
| /** |
| * Checks if a RegExp-Matcher is available. |
| * @param project The project to check for (may be <code>null</code>) |
| * @return <code>true</code> if available otherwise <code>false</code> |
| */ |
| public static boolean regexpMatcherPresent(Project project) { |
| try { |
| // The factory throws a BuildException if no usable matcher |
| // cannot be instantiated. We don't need the matcher itself here. |
| new RegexpMatcherFactory().newRegexpMatcher(project); |
| return true; |
| } catch (Throwable ex) { |
| return false; |
| } |
| } |
| } |