com.greenpepper.shaded.org.apache.tools.ant.util.regexp.RegexpMatcherFactory Maven / Gradle / Ivy
/*
* 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
*
* 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 com.greenpepper.shaded.org.apache.tools.ant.util.regexp;
import com.greenpepper.shaded.org.apache.tools.ant.Project;
import com.greenpepper.shaded.org.apache.tools.ant.MagicNames;
import com.greenpepper.shaded.org.apache.tools.ant.BuildException;
import com.greenpepper.shaded.org.apache.tools.ant.util.ClasspathUtils;
import com.greenpepper.shaded.org.apache.tools.ant.util.JavaEnvUtils;
/**
* Simple Factory Class that produces an implementation of
* RegexpMatcher based on the system property
* ant.regexp.regexpimpl
and the classes
* available.
*
* In a more general framework this class would be abstract and
* have a static newInstance method.
*
*/
public class RegexpMatcherFactory {
/** Constructor for RegexpMatcherFactory. */
public 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 = null;
if (p == null) {
systemDefault = System.getProperty(MagicNames.REGEXP_IMPL);
} else {
systemDefault = p.getProperty(MagicNames.REGEXP_IMPL);
}
if (systemDefault != null) {
return createInstance(systemDefault);
// XXX should we silently catch possible exceptions and try to
// load a different implementation?
}
Throwable cause = null;
try {
testAvailability("java.util.regex.Matcher");
return createInstance("com.greenpepper.shaded.org.apache.tools.ant.util.regexp.Jdk14RegexpMatcher");
} catch (BuildException be) {
cause = orCause(cause, be, JavaEnvUtils.getJavaVersionNumber() < 14);
}
try {
testAvailability("org.apache.oro.text.regex.Pattern");
return createInstance("com.greenpepper.shaded.org.apache.tools.ant.util.regexp.JakartaOroMatcher");
} catch (BuildException be) {
cause = orCause(cause, be, true);
}
try {
testAvailability("org.apache.regexp.RE");
return createInstance("com.greenpepper.shaded.org.apache.tools.ant.util.regexp.JakartaRegexpMatcher");
} catch (BuildException be) {
cause = orCause(cause, be, true);
}
throw new BuildException(
"No supported regular expression matcher found"
+ (cause != null ? ": " + cause : ""), cause);
}
static Throwable orCause(Throwable deflt, BuildException be, boolean ignoreCnfe) {
if (deflt != null) {
return deflt;
}
Throwable t = be.getException();
return ignoreCnfe && t instanceof ClassNotFoundException ? null : t;
}
/**
* Create an instance of a matcher from a classname.
*
* @param className a String
value
* @return a RegexpMatcher
value
* @exception BuildException if an error occurs
*/
protected RegexpMatcher createInstance(String className)
throws BuildException {
return (RegexpMatcher) ClasspathUtils.newInstance(className,
RegexpMatcherFactory.class.getClassLoader(), RegexpMatcher.class);
}
/**
* Test if a particular class is available to be used.
*
* @param className a String
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);
}
}
}