org.apache.tools.ant.taskdefs.Classloader Maven / Gradle / Ivy
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* 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 org.apache.tools.ant.taskdefs;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.MagicNames;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.AntClassLoader;
import org.apache.tools.ant.types.Reference;
import org.apache.tools.ant.types.Path;
import java.io.File;
/**
* EXPERIMENTAL
* Create or modifies ClassLoader. The required pathRef parameter
* will be used to add classpath elements.
*
* The classpath is a regular path. Currently only file components are
* supported (future extensions may allow URLs).
*
* You can modify the core loader by not specifying any name or using
* "ant.coreLoader". (the core loader is used to load system ant
* tasks and for taskdefs that don't specify an explicit path).
*
* Taskdef and typedef can use the loader you create if the name follows
* the "ant.loader.NAME" pattern. NAME will be used as a pathref when
* calling taskdef.
*
* This tasks will not modify the core loader if "build.sysclasspath=only"
*
* The typical use is:
*
* <path id="ant.deps" >
* <fileset dir="myDir" >
* <include name="junit.jar, bsf.jar, js.jar, etc"/>
* </fileset>
* </path>
*
* <classloader pathRef="ant.deps" />
*
*
*
*/
public class Classloader extends Task {
/** @see MagicNames#SYSTEM_LOADER_REF */
public static final String SYSTEM_LOADER_REF = MagicNames.SYSTEM_LOADER_REF;
private String name = null;
private Path classpath;
private boolean reset = false;
private boolean parentFirst = true;
private String parentName = null;
/**
* Default constructor
*/
public Classloader() {
}
/** Name of the loader. If none, the default loader will be modified
*
* @param name the name of this loader
*/
public void setName(String name) {
this.name = name;
}
/**
* Reset the classloader, if it already exists. A new loader will
* be created and all the references to the old one will be removed.
* (it is not possible to remove paths from a loader). The new
* path will be used.
*
* @param b true if the loader is to be reset.
*/
public void setReset(boolean b) {
this.reset = b;
}
/**
* Set reverse attribute.
* @param b if true reverse the normal classloader lookup.
* @deprecated use setParentFirst with a negated argument instead
*/
public void setReverse(boolean b) {
this.parentFirst = !b;
}
/**
* Set reverse attribute.
* @param b if true reverse the normal classloader lookup.
*/
public void setParentFirst(boolean b) {
this.parentFirst = b;
}
/**
* Set the name of the parent.
* @param name the parent name.
*/
public void setParentName(String name) {
this.parentName = name;
}
/** Specify which path will be used. If the loader already exists
* and is an AntClassLoader (or any other loader we can extend),
* the path will be added to the loader.
* @param pathRef a reference to a path.
* @throws BuildException if there is a problem.
*/
public void setClasspathRef(Reference pathRef) throws BuildException {
classpath = (Path) pathRef.getReferencedObject(getProject());
}
/**
* Set the classpath to be used when searching for component being defined
*
* @param classpath an Ant Path object containing the classpath.
*/
public void setClasspath(Path classpath) {
if (this.classpath == null) {
this.classpath = classpath;
} else {
this.classpath.append(classpath);
}
}
/**
* Create a classpath.
* @return a path for configuration.
*/
public Path createClasspath() {
if (this.classpath == null) {
this.classpath = new Path(null);
}
return this.classpath.createPath();
}
/**
* do the classloader manipulation.
*/
public void execute() {
try {
// Gump friendly - don't mess with the core loader if only classpath
if ("only".equals(getProject().getProperty("build.sysclasspath"))
&& (name == null || SYSTEM_LOADER_REF.equals(name))) {
log("Changing the system loader is disabled "
+ "by build.sysclasspath=only", Project.MSG_WARN);
return;
}
String loaderName = (name == null) ? SYSTEM_LOADER_REF : name;
Object obj = getProject().getReference(loaderName);
if (reset) {
// Are any other references held ? Can we 'close' the loader
// so it removes the locks on jars ?
obj = null; // a new one will be created.
}
// XXX maybe use reflection to addPathElement (other patterns ?)
if (obj != null && !(obj instanceof AntClassLoader)) {
log("Referenced object is not an AntClassLoader",
Project.MSG_ERR);
return;
}
AntClassLoader acl = (AntClassLoader) obj;
boolean existingLoader = acl != null;
if (acl == null) {
// Construct a new class loader
Object parent = null;
if (parentName != null) {
parent = getProject().getReference(parentName);
if (!(parent instanceof ClassLoader)) {
parent = null;
}
}
// TODO: allow user to request the system or no parent
if (parent == null) {
parent = this.getClass().getClassLoader();
}
if (name == null) {
// The core loader must be reverse
//reverse=true;
}
getProject().log("Setting parent loader " + name + " "
+ parent + " " + parentFirst, Project.MSG_DEBUG);
// The param is "parentFirst"
acl = AntClassLoader.newAntClassLoader((ClassLoader) parent,
getProject(), classpath, parentFirst);
getProject().addReference(loaderName, acl);
if (name == null) {
// This allows the core loader to load optional tasks
// without delegating
acl.addLoaderPackageRoot("org.apache.tools.ant.taskdefs.optional");
getProject().setCoreLoader(acl);
}
}
if (existingLoader && classpath != null) {
String[] list = classpath.list();
for (int i = 0; i < list.length; i++) {
File f = new File(list[i]);
if (f.exists()) {
log("Adding to class loader " + acl + " " + f.getAbsolutePath(),
Project.MSG_DEBUG);
acl.addPathElement(f.getAbsolutePath());
}
}
}
// XXX add exceptions
} catch (Exception ex) {
ex.printStackTrace();
}
}
}