Ant example source code file (AntClassLoader.java)
The AntClassLoader.java source code
/*
* 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;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.lang.reflect.Constructor;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.jar.Attributes;
import java.util.jar.Attributes.Name;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.util.CollectionUtils;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.JavaEnvUtils;
import org.apache.tools.ant.util.LoaderUtils;
import org.apache.tools.ant.launch.Locator;
/**
* Used to load classes within ant with a different classpath from
* that used to start ant. Note that it is possible to force a class
* into this loader even when that class is on the system classpath by
* using the forceLoadClass method. Any subsequent classes loaded by that
* class will then use this loader rather than the system class loader.
*
* <p>
* Note that this classloader has a feature to allow loading
* in reverse order and for "isolation".
* Due to the fact that a number of
* methods in java.lang.ClassLoader are final (at least
* in java 1.4 getResources) this means that the
* class has to fake the given parent.
* </p>
*
*/
public class AntClassLoader extends ClassLoader implements SubBuildListener {
private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
/**
* An enumeration of all resources of a given name found within the
* classpath of this class loader. This enumeration is used by the
* ClassLoader.findResources method, which is in
* turn used by the ClassLoader.getResources method.
*
* @see AntClassLoader#findResources(String)
* @see java.lang.ClassLoader#getResources(String)
*/
private class ResourceEnumeration implements Enumeration {
/**
* The name of the resource being searched for.
*/
private String resourceName;
/**
* The index of the next classpath element to search.
*/
private int pathElementsIndex;
/**
* The URL of the next resource to return in the enumeration. If this
* field is <code>null then the enumeration has been completed,
* i.e., there are no more elements to return.
*/
private URL nextResource;
/**
* Constructs a new enumeration of resources of the given name found
* within this class loader's classpath.
*
* @param name the name of the resource to search for.
*/
ResourceEnumeration(String name) {
this.resourceName = name;
this.pathElementsIndex = 0;
findNextResource();
}
/**
* Indicates whether there are more elements in the enumeration to
* return.
*
* @return <code>true if there are more elements in the
* enumeration; <code>false otherwise.
*/
public boolean hasMoreElements() {
return (this.nextResource != null);
}
/**
* Returns the next resource in the enumeration.
*
* @return the next resource in the enumeration
*/
public Object nextElement() {
URL ret = this.nextResource;
findNextResource();
return ret;
}
/**
* Locates the next resource of the correct name in the classpath and
* sets <code>nextResource to the URL of that resource. If no
* more resources can be found, <code>nextResource is set to
* <code>null.
*/
private void findNextResource() {
URL url = null;
while ((pathElementsIndex < pathComponents.size())
&& (url == null)) {
try {
File pathComponent
= (File) pathComponents.elementAt(pathElementsIndex);
url = getResourceURL(pathComponent, this.resourceName);
pathElementsIndex++;
} catch (BuildException e) {
// ignore path elements which are not valid relative to the
// project
}
}
this.nextResource = url;
}
}
/**
* The size of buffers to be used in this classloader.
*/
private static final int BUFFER_SIZE = 8192;
/**
* Number of array elements in a test array of strings
*/
private static final int NUMBER_OF_STRINGS = 256;
/**
* The components of the classpath that the classloader searches
* for classes.
*/
private Vector pathComponents = new Vector();
/**
* The project to which this class loader belongs.
*/
private Project project;
/**
* Indicates whether the parent class loader should be
* consulted before trying to load with this class loader.
*/
private boolean parentFirst = true;
/**
* These are the package roots that are to be loaded by the parent class
* loader regardless of whether the parent class loader is being searched
* first or not.
*/
private Vector systemPackages = new Vector();
/**
* These are the package roots that are to be loaded by this class loader
* regardless of whether the parent class loader is being searched first
* or not.
*/
private Vector loaderPackages = new Vector();
/**
* Whether or not this classloader will ignore the base
* classloader if it can't find a class.
*
* @see #setIsolated(boolean)
*/
private boolean ignoreBase = false;
/**
* The parent class loader, if one is given or can be determined.
*/
private ClassLoader parent = null;
/**
* A hashtable of zip files opened by the classloader (File to ZipFile).
*/
private Hashtable zipFiles = new Hashtable();
/** Static map of jar file/time to manifiest class-path entries */
private static Map/*<String,String>*/ pathMap = Collections.synchronizedMap(new HashMap());
/**
* The context loader saved when setting the thread's current
* context loader.
*/
private ClassLoader savedContextLoader = null;
/**
* Whether or not the context loader is currently saved.
*/
private boolean isContextLoaderSaved = false;
/**
* Create an Ant ClassLoader for a given project, with
* a parent classloader and an initial classpath.
* @since Ant 1.7.
* @param parent the parent for this classloader.
* @param project The project to which this classloader is to
* belong.
* @param classpath The classpath to use to load classes.
*/
public AntClassLoader(
ClassLoader parent, Project project, Path classpath) {
setParent(parent);
setClassPath(classpath);
setProject(project);
}
/**
* Create an Ant Class Loader
*/
public AntClassLoader() {
setParent(null);
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param project The project to which this classloader is to belong.
* Must not be <code>null.
* @param classpath The classpath to use to load the classes. This
* is combined with the system classpath in a manner
* determined by the value of ${build.sysclasspath}.
* May be <code>null, in which case no path
* elements are set up to start with.
*/
public AntClassLoader(Project project, Path classpath) {
setParent(null);
setProject(project);
setClassPath(classpath);
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param parent The parent classloader to which unsatisfied loading
* attempts are delegated. May be <code>null,
* in which case the classloader which loaded this
* class is used as the parent.
* @param project The project to which this classloader is to belong.
* Must not be <code>null.
* @param classpath the classpath to use to load the classes.
* May be <code>null, in which case no path
* elements are set up to start with.
* @param parentFirst If <code>true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(ClassLoader parent, Project project, Path classpath,
boolean parentFirst) {
this(project, classpath);
if (parent != null) {
setParent(parent);
}
setParentFirst(parentFirst);
addJavaLibraries();
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param project The project to which this classloader is to belong.
* Must not be <code>null.
* @param classpath The classpath to use to load the classes. May be
* <code>null, in which case no path
* elements are set up to start with.
* @param parentFirst If <code>true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(Project project, Path classpath,
boolean parentFirst) {
this(null, project, classpath, parentFirst);
}
/**
* Creates an empty class loader. The classloader should be configured
* with path elements to specify where the loader is to look for
* classes.
*
* @param parent The parent classloader to which unsatisfied loading
* attempts are delegated. May be <code>null,
* in which case the classloader which loaded this
* class is used as the parent.
* @param parentFirst If <code>true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(ClassLoader parent, boolean parentFirst) {
setParent(parent);
project = null;
this.parentFirst = parentFirst;
}
/**
* Set the project associated with this class loader
*
* @param project the project instance
*/
public void setProject(Project project) {
this.project = project;
if (project != null) {
project.addBuildListener(this);
}
}
/**
* Set the classpath to search for classes to load. This should not be
* changed once the classloader starts to server classes
*
* @param classpath the search classpath consisting of directories and
* jar/zip files.
*/
public void setClassPath(Path classpath) {
pathComponents.removeAllElements();
if (classpath != null) {
Path actualClasspath = classpath.concatSystemClasspath("ignore");
String[] pathElements = actualClasspath.list();
for (int i = 0; i < pathElements.length; ++i) {
try {
addPathElement(pathElements[i]);
} catch (BuildException e) {
// ignore path elements which are invalid
// relative to the project
}
}
}
}
/**
* Set the parent for this class loader. This is the class loader to which
* this class loader will delegate to load classes
*
* @param parent the parent class loader.
*/
public void setParent(ClassLoader parent) {
if (parent == null) {
this.parent = AntClassLoader.class.getClassLoader();
} else {
this.parent = parent;
}
}
/**
* Control whether class lookup is delegated to the parent loader first
* or after this loader. Use with extreme caution. Setting this to
* false violates the class loader hierarchy and can lead to Linkage errors
*
* @param parentFirst if true, delegate initial class search to the parent
* classloader.
*/
public void setParentFirst(boolean parentFirst) {
this.parentFirst = parentFirst;
}
/**
* Logs a message through the project object if one has been provided.
*
* @param message The message to log.
* Should not be <code>null.
*
* @param priority The logging priority of the message.
*/
protected void log(String message, int priority) {
if (project != null) {
project.log(message, priority);
}
// else {
// System.out.println(message);
// }
}
/**
* Sets the current thread's context loader to this classloader, storing
* the current loader value for later resetting.
*/
public void setThreadContextLoader() {
if (isContextLoaderSaved) {
throw new BuildException("Context loader has not been reset");
}
if (LoaderUtils.isContextLoaderAvailable()) {
savedContextLoader = LoaderUtils.getContextClassLoader();
ClassLoader loader = this;
if (project != null
&& "only".equals(project.getProperty("build.sysclasspath"))) {
loader = this.getClass().getClassLoader();
}
LoaderUtils.setContextClassLoader(loader);
isContextLoaderSaved = true;
}
}
/**
* Resets the current thread's context loader to its original value.
*/
public void resetThreadContextLoader() {
if (LoaderUtils.isContextLoaderAvailable()
&& isContextLoaderSaved) {
LoaderUtils.setContextClassLoader(savedContextLoader);
savedContextLoader = null;
isContextLoaderSaved = false;
}
}
/**
* Adds an element to the classpath to be searched.
*
* @param pathElement The path element to add. Must not be
* <code>null.
*
* @exception BuildException if the given path element cannot be resolved
* against the project.
*/
public void addPathElement(String pathElement) throws BuildException {
File pathComponent
= project != null ? project.resolveFile(pathElement)
: new File(pathElement);
try {
addPathFile(pathComponent);
} catch (IOException e) {
throw new BuildException(e);
}
}
/**
* Add a file to the path.
* Reads the manifest, if available, and adds any additional class path jars
* specified in the manifest.
*
* @param pathComponent the file which is to be added to the path for
* this class loader
*
* @throws IOException if data needed from the file cannot be read.
*/
protected void addPathFile(File pathComponent) throws IOException {
pathComponents.addElement(pathComponent);
if (pathComponent.isDirectory()) {
return;
}
String absPathPlusTimeAndLength =
pathComponent.getAbsolutePath() + pathComponent.lastModified() + "-"
+ pathComponent.length();
String classpath = (String) pathMap.get(absPathPlusTimeAndLength);
if (classpath == null) {
ZipFile jarFile = null;
InputStream manifestStream = null;
try {
jarFile = new ZipFile(pathComponent);
manifestStream
= jarFile.getInputStream(new ZipEntry("META-INF/MANIFEST.MF"));
if (manifestStream == null) {
return;
}
Reader manifestReader
= new InputStreamReader(manifestStream, "UTF-8");
org.apache.tools.ant.taskdefs.Manifest manifest
= new org.apache.tools.ant.taskdefs.Manifest(manifestReader);
classpath
= manifest.getMainSection().getAttributeValue("Class-Path");
} catch (org.apache.tools.ant.taskdefs.ManifestException e) {
// ignore
} finally {
if (manifestStream != null) {
manifestStream.close();
}
if (jarFile != null) {
jarFile.close();
}
}
if (classpath == null) {
classpath = "";
}
pathMap.put(absPathPlusTimeAndLength, classpath);
}
if (!"".equals(classpath)) {
URL baseURL = FILE_UTILS.getFileURL(pathComponent);
StringTokenizer st = new StringTokenizer(classpath);
while (st.hasMoreTokens()) {
String classpathElement = st.nextToken();
URL libraryURL = new URL(baseURL, classpathElement);
if (!libraryURL.getProtocol().equals("file")) {
log("Skipping jar library " + classpathElement
+ " since only relative URLs are supported by this"
+ " loader", Project.MSG_VERBOSE);
continue;
}
String decodedPath = Locator.decodeUri(libraryURL.getFile());
File libraryFile = new File(decodedPath);
if (libraryFile.exists() && !isInPath(libraryFile)) {
addPathFile(libraryFile);
}
}
}
}
/**
* Returns the classpath this classloader will consult.
*
* @return the classpath used for this classloader, with elements
* separated by the path separator for the system.
*/
public String getClasspath() {
StringBuffer sb = new StringBuffer();
boolean firstPass = true;
Enumeration componentEnum = pathComponents.elements();
while (componentEnum.hasMoreElements()) {
if (!firstPass) {
sb.append(System.getProperty("path.separator"));
} else {
firstPass = false;
}
sb.append(((File) componentEnum.nextElement()).getAbsolutePath());
}
return sb.toString();
}
/**
* Sets whether this classloader should run in isolated mode. In
* isolated mode, classes not found on the given classpath will
* not be referred to the parent class loader but will cause a
* ClassNotFoundException.
*
* @param isolated Whether or not this classloader should run in
* isolated mode.
*/
public synchronized void setIsolated(boolean isolated) {
ignoreBase = isolated;
}
/**
* Forces initialization of a class in a JDK 1.1 compatible, albeit hacky
* way.
*
* @param theClass The class to initialize.
* Must not be <code>null.
*
* @deprecated since 1.6.x.
* Use Class.forName with initialize=true instead.
*/
public static void initializeClass(Class theClass) {
// ***HACK*** We ask the VM to create an instance
// by voluntarily providing illegal arguments to force
// the VM to run the class' static initializer, while
// at the same time not running a valid constructor.
final Constructor[] cons = theClass.getDeclaredConstructors();
//At least one constructor is guaranteed to be there, but check anyway.
if (cons != null) {
if (cons.length > 0 && cons[0] != null) {
final String[] strs = new String[NUMBER_OF_STRINGS];
try {
cons[0].newInstance((Object[]) strs);
// Expecting an exception to be thrown by this call:
// IllegalArgumentException: wrong number of Arguments
} catch (Exception e) {
// Ignore - we are interested only in the side
// effect - that of getting the static initializers
// invoked. As we do not want to call a valid
// constructor to get this side effect, an
// attempt is made to call a hopefully
// invalid constructor - come on, nobody
// would have a constructor that takes in
// 256 String arguments ;-)
// (In fact, they can't - according to JVM spec
// section 4.10, the number of method parameters is limited
// to 255 by the definition of a method descriptor.
// Constructors count as methods here.)
}
}
}
}
/**
* Adds a package root to the list of packages which must be loaded on the
* parent loader.
*
* All subpackages are also included.
*
* @param packageRoot The root of all packages to be included.
* Should not be <code>null.
*/
public void addSystemPackageRoot(String packageRoot) {
systemPackages.addElement(packageRoot
+ (packageRoot.endsWith(".") ? "" : "."));
}
/**
* Adds a package root to the list of packages which must be loaded using
* this loader.
*
* All subpackages are also included.
*
* @param packageRoot The root of all packages to be included.
* Should not be <code>null.
*/
public void addLoaderPackageRoot(String packageRoot) {
loaderPackages.addElement(packageRoot
+ (packageRoot.endsWith(".") ? "" : "."));
}
/**
* Loads a class through this class loader even if that class is available
* on the parent classpath.
*
* This ensures that any classes which are loaded by the returned class
* will use this classloader.
*
* @param classname The name of the class to be loaded.
* Must not be <code>null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
public Class forceLoadClass(String classname)
throws ClassNotFoundException {
log("force loading " + classname, Project.MSG_DEBUG);
Class theClass = findLoadedClass(classname);
if (theClass == null) {
theClass = findClass(classname);
}
return theClass;
}
/**
* Loads a class through this class loader but defer to the parent class
* loader.
*
* This ensures that instances of the returned class will be compatible
* with instances which have already been loaded on the parent
* loader.
*
* @param classname The name of the class to be loaded.
* Must not be <code>null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
public Class forceLoadSystemClass(String classname)
throws ClassNotFoundException {
log("force system loading " + classname, Project.MSG_DEBUG);
Class theClass = findLoadedClass(classname);
if (theClass == null) {
theClass = findBaseClass(classname);
}
return theClass;
}
/**
* Returns a stream to read the requested resource name.
*
* @param name The name of the resource for which a stream is required.
* Must not be <code>null.
*
* @return a stream to the required resource or <code>null if the
* resource cannot be found on the loader's classpath.
*/
public InputStream getResourceAsStream(String name) {
InputStream resourceStream = null;
if (isParentFirst(name)) {
resourceStream = loadBaseResource(name);
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from parent loader", Project.MSG_DEBUG);
} else {
resourceStream = loadResource(name);
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from ant loader", Project.MSG_DEBUG);
}
}
} else {
resourceStream = loadResource(name);
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from ant loader", Project.MSG_DEBUG);
} else {
resourceStream = loadBaseResource(name);
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from parent loader", Project.MSG_DEBUG);
}
}
}
if (resourceStream == null) {
log("Couldn't load ResourceStream for " + name,
Project.MSG_DEBUG);
}
return resourceStream;
}
/**
* Returns a stream to read the requested resource name from this loader.
*
* @param name The name of the resource for which a stream is required.
* Must not be <code>null.
*
* @return a stream to the required resource or <code>null if
* the resource cannot be found on the loader's classpath.
*/
private InputStream loadResource(String name) {
// we need to search the components of the path to see if we can
// find the class we want.
InputStream stream = null;
Enumeration e = pathComponents.elements();
while (e.hasMoreElements() && stream == null) {
File pathComponent = (File) e.nextElement();
stream = getResourceStream(pathComponent, name);
}
return stream;
}
/**
* Finds a system resource (which should be loaded from the parent
* classloader).
*
* @param name The name of the system resource to load.
* Must not be <code>null.
*
* @return a stream to the named resource, or <code>null if
* the resource cannot be found.
*/
private InputStream loadBaseResource(String name) {
if (parent == null) {
return getSystemResourceAsStream(name);
} else {
return parent.getResourceAsStream(name);
}
}
/**
* Returns an inputstream to a given resource in the given file which may
* either be a directory or a zip file.
*
* @param file the file (directory or jar) in which to search for the
* resource. Must not be <code>null.
* @param resourceName The name of the resource for which a stream is
* required. Must not be <code>null.
*
* @return a stream to the required resource or <code>null if
* the resource cannot be found in the given file.
*/
private InputStream getResourceStream(File file, String resourceName) {
try {
if (!file.exists()) {
return null;
}
if (file.isDirectory()) {
File resource = new File(file, resourceName);
if (resource.exists()) {
return new FileInputStream(resource);
}
} else {
// is the zip file in the cache
ZipFile zipFile = (ZipFile) zipFiles.get(file);
if (zipFile == null) {
zipFile = new ZipFile(file);
zipFiles.put(file, zipFile);
}
ZipEntry entry = zipFile.getEntry(resourceName);
if (entry != null) {
return zipFile.getInputStream(entry);
}
}
} catch (Exception e) {
log("Ignoring Exception " + e.getClass().getName()
+ ": " + e.getMessage() + " reading resource " + resourceName
+ " from " + file, Project.MSG_VERBOSE);
}
return null;
}
/**
* Tests whether or not the parent classloader should be checked for
* a resource before this one. If the resource matches both the
* "use parent classloader first" and the "use this classloader first"
* lists, the latter takes priority.
*
* @param resourceName The name of the resource to check.
* Must not be <code>null.
*
* @return whether or not the parent classloader should be checked for a
* resource before this one is.
*/
private boolean isParentFirst(String resourceName) {
// default to the global setting and then see
// if this class belongs to a package which has been
// designated to use a specific loader first
// (this one or the parent one)
// XXX - shouldn't this always return false in isolated mode?
boolean useParentFirst = parentFirst;
for (Enumeration e = systemPackages.elements(); e.hasMoreElements();) {
String packageName = (String) e.nextElement();
if (resourceName.startsWith(packageName)) {
useParentFirst = true;
break;
}
}
for (Enumeration e = loaderPackages.elements(); e.hasMoreElements();) {
String packageName = (String) e.nextElement();
if (resourceName.startsWith(packageName)) {
useParentFirst = false;
break;
}
}
return useParentFirst;
}
/**
* Used for isolated resource seaching.
* @return the root classloader of AntClassLoader.
*/
private ClassLoader getRootLoader() {
ClassLoader ret = getClass().getClassLoader();
while (ret != null && ret.getParent() != null) {
ret = ret.getParent();
}
return ret;
}
/**
* Finds the resource with the given name. A resource is
* some data (images, audio, text, etc) that can be accessed by class
* code in a way that is independent of the location of the code.
*
* @param name The name of the resource for which a stream is required.
* Must not be <code>null.
*
* @return a URL for reading the resource, or <code>null if the
* resource could not be found or the caller doesn't have
* adequate privileges to get the resource.
*/
public URL getResource(String name) {
// we need to search the components of the path to see if
// we can find the class we want.
URL url = null;
if (isParentFirst(name)) {
url = (parent == null) ? super.getResource(name)
: parent.getResource(name);
}
if (url != null) {
log("Resource " + name + " loaded from parent loader",
Project.MSG_DEBUG);
} else {
// try and load from this loader if the parent either didn't find
// it or wasn't consulted.
Enumeration e = pathComponents.elements();
while (e.hasMoreElements() && url == null) {
File pathComponent = (File) e.nextElement();
url = getResourceURL(pathComponent, name);
if (url != null) {
log("Resource " + name
+ " loaded from ant loader",
Project.MSG_DEBUG);
}
}
}
if (url == null && !isParentFirst(name)) {
// this loader was first but it didn't find it - try the parent
if (ignoreBase) {
url = (getRootLoader() == null) ? null
: getRootLoader().getResource(name);
} else {
url = (parent == null) ? super.getResource(name)
: parent.getResource(name);
}
if (url != null) {
log("Resource " + name + " loaded from parent loader",
Project.MSG_DEBUG);
}
}
if (url == null) {
log("Couldn't load Resource " + name, Project.MSG_DEBUG);
}
return url;
}
/**
* Returns an enumeration of URLs representing all the resources with the
* given name by searching the class loader's classpath.
*
* @param name The resource name to search for.
* Must not be <code>null.
* @return an enumeration of URLs for the resources
* @exception IOException if I/O errors occurs (can't happen)
*/
protected Enumeration/*<URL>*/ findResources(String name) throws IOException {
Enumeration/*<URL>*/ mine = new ResourceEnumeration(name);
Enumeration/*<URL>*/ base;
if (parent != null && parent != getParent()) {
// Delegate to the parent:
base = parent.getResources(name);
// Note: could cause overlaps in case ClassLoader.this.parent has matches.
} else {
// ClassLoader.this.parent is already delegated to from
// ClassLoader.getResources, no need:
base = new CollectionUtils.EmptyEnumeration();
}
if (isParentFirst(name)) {
// Normal case.
return CollectionUtils.append(base, mine);
} else if (ignoreBase) {
return getRootLoader() == null
? mine
: CollectionUtils.append(
mine, getRootLoader().getResources(name));
} else {
// Inverted.
return CollectionUtils.append(mine, base);
}
}
/**
* Returns the URL of a given resource in the given file which may
* either be a directory or a zip file.
*
* @param file The file (directory or jar) in which to search for
* the resource. Must not be <code>null.
* @param resourceName The name of the resource for which a stream
* is required. Must not be <code>null.
*
* @return a stream to the required resource or <code>null if the
* resource cannot be found in the given file object.
*/
protected URL getResourceURL(File file, String resourceName) {
try {
if (!file.exists()) {
return null;
}
if (file.isDirectory()) {
File resource = new File(file, resourceName);
if (resource.exists()) {
try {
return FILE_UTILS.getFileURL(resource);
} catch (MalformedURLException ex) {
return null;
}
}
} else {
ZipFile zipFile = (ZipFile) zipFiles.get(file);
if (zipFile == null) {
zipFile = new ZipFile(file);
zipFiles.put(file, zipFile);
}
ZipEntry entry = zipFile.getEntry(resourceName);
if (entry != null) {
try {
return new URL("jar:" + FILE_UTILS.getFileURL(file)
+ "!/" + entry);
} catch (MalformedURLException ex) {
return null;
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* Loads a class with this class loader.
*
* This class attempts to load the class in an order determined by whether
* or not the class matches the system/loader package lists, with the
* loader package list taking priority. If the classloader is in isolated
* mode, failure to load the class in this loader will result in a
* ClassNotFoundException.
*
* @param classname The name of the class to be loaded.
* Must not be <code>null.
* @param resolve <code>true if all classes upon which this class
* depends are to be loaded.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on the system classpath (when not in isolated mode) or this loader's
* classpath.
*/
protected synchronized Class loadClass(String classname, boolean resolve)
throws ClassNotFoundException {
// 'sync' is needed - otherwise 2 threads can load the same class
// twice, resulting in LinkageError: duplicated class definition.
// findLoadedClass avoids that, but without sync it won't work.
Class theClass = findLoadedClass(classname);
if (theClass != null) {
return theClass;
}
if (isParentFirst(classname)) {
try {
theClass = findBaseClass(classname);
log("Class " + classname + " loaded from parent loader "
+ "(parentFirst)", Project.MSG_DEBUG);
} catch (ClassNotFoundException cnfe) {
theClass = findClass(classname);
log("Class " + classname + " loaded from ant loader "
+ "(parentFirst)", Project.MSG_DEBUG);
}
} else {
try {
theClass = findClass(classname);
log("Class " + classname + " loaded from ant loader",
Project.MSG_DEBUG);
} catch (ClassNotFoundException cnfe) {
if (ignoreBase) {
throw cnfe;
}
theClass = findBaseClass(classname);
log("Class " + classname + " loaded from parent loader",
Project.MSG_DEBUG);
}
}
if (resolve) {
resolveClass(theClass);
}
return theClass;
}
/**
* Converts the class dot notation to a filesystem equivalent for
* searching purposes.
*
* @param classname The class name in dot format (eg java.lang.Integer).
* Must not be <code>null.
*
* @return the classname in filesystem format (eg java/lang/Integer.class)
*/
private String getClassFilename(String classname) {
return classname.replace('.', '/') + ".class";
}
/**
* Define a class given its bytes
*
* @param container the container from which the class data has been read
* may be a directory or a jar/zip file.
*
* @param classData the bytecode data for the class
* @param classname the name of the class
*
* @return the Class instance created from the given data
*
* @throws IOException if the class data cannot be read.
*/
protected Class defineClassFromData(File container, byte[] classData,
String classname) throws IOException {
definePackage(container, classname);
// XXX should instead make a new ProtectionDomain with a CodeSource
// corresponding to container.toURI().toURL() and the same
// PermissionCollection as Project.class.protectionDomain had
return defineClass(classname, classData, 0, classData.length,
Project.class.getProtectionDomain());
}
/**
* Define the package information associated with a class.
*
* @param container the file containing the class definition.
* @param className the class name of for which the package information
* is to be determined.
*
* @exception IOException if the package information cannot be read from the
* container.
*/
protected void definePackage(File container, String className)
throws IOException {
int classIndex = className.lastIndexOf('.');
if (classIndex == -1) {
return;
}
String packageName = className.substring(0, classIndex);
if (getPackage(packageName) != null) {
// already defined
return;
}
// define the package now
Manifest manifest = getJarManifest(container);
if (manifest == null) {
definePackage(packageName, null, null, null, null, null,
null, null);
} else {
definePackage(container, packageName, manifest);
}
}
/**
* Get the manifest from the given jar, if it is indeed a jar and it has a
* manifest
*
* @param container the File from which a manifest is required.
*
* @return the jar's manifest or null is the container is not a jar or it
* has no manifest.
*
* @exception IOException if the manifest cannot be read.
*/
private Manifest getJarManifest(File container) throws IOException {
if (container.isDirectory()) {
return null;
}
JarFile jarFile = null;
try {
jarFile = new JarFile(container);
return jarFile.getManifest();
} finally {
if (jarFile != null) {
jarFile.close();
}
}
}
/**
* Define the package information when the class comes from a
* jar with a manifest
*
* @param container the jar file containing the manifest
* @param packageName the name of the package being defined.
* @param manifest the jar's manifest
*/
protected void definePackage(File container, String packageName,
Manifest manifest) {
String sectionName = packageName.replace('.', '/') + "/";
String specificationTitle = null;
String specificationVendor = null;
String specificationVersion = null;
String implementationTitle = null;
String implementationVendor = null;
String implementationVersion = null;
String sealedString = null;
URL sealBase = null;
Attributes sectionAttributes = manifest.getAttributes(sectionName);
if (sectionAttributes != null) {
specificationTitle
= sectionAttributes.getValue(Name.SPECIFICATION_TITLE);
specificationVendor
= sectionAttributes.getValue(Name.SPECIFICATION_VENDOR);
specificationVersion
= sectionAttributes.getValue(Name.SPECIFICATION_VERSION);
implementationTitle
= sectionAttributes.getValue(Name.IMPLEMENTATION_TITLE);
implementationVendor
= sectionAttributes.getValue(Name.IMPLEMENTATION_VENDOR);
implementationVersion
= sectionAttributes.getValue(Name.IMPLEMENTATION_VERSION);
sealedString
= sectionAttributes.getValue(Name.SEALED);
}
Attributes mainAttributes = manifest.getMainAttributes();
if (mainAttributes != null) {
if (specificationTitle == null) {
specificationTitle
= mainAttributes.getValue(Name.SPECIFICATION_TITLE);
}
if (specificationVendor == null) {
specificationVendor
= mainAttributes.getValue(Name.SPECIFICATION_VENDOR);
}
if (specificationVersion == null) {
specificationVersion
= mainAttributes.getValue(Name.SPECIFICATION_VERSION);
}
if (implementationTitle == null) {
implementationTitle
= mainAttributes.getValue(Name.IMPLEMENTATION_TITLE);
}
if (implementationVendor == null) {
implementationVendor
= mainAttributes.getValue(Name.IMPLEMENTATION_VENDOR);
}
if (implementationVersion == null) {
implementationVersion
= mainAttributes.getValue(Name.IMPLEMENTATION_VERSION);
}
if (sealedString == null) {
sealedString
= mainAttributes.getValue(Name.SEALED);
}
}
if (sealedString != null && sealedString.equalsIgnoreCase("true")) {
try {
sealBase = new URL(FileUtils.getFileUtils().toURI(container.getAbsolutePath()));
} catch (MalformedURLException e) {
// ignore
}
}
definePackage(packageName, specificationTitle, specificationVersion,
specificationVendor, implementationTitle,
implementationVersion, implementationVendor, sealBase);
}
/**
* Reads a class definition from a stream.
*
* @param stream The stream from which the class is to be read.
* Must not be <code>null.
* @param classname The name of the class in the stream.
* Must not be <code>null.
* @param container the file or directory containing the class.
*
* @return the Class object read from the stream.
*
* @exception IOException if there is a problem reading the class from the
* stream.
* @exception SecurityException if there is a security problem while
* reading the class from the stream.
*/
private Class getClassFromStream(InputStream stream, String classname,
File container)
throws IOException, SecurityException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int bytesRead = -1;
byte[] buffer = new byte[BUFFER_SIZE];
while ((bytesRead = stream.read(buffer, 0, BUFFER_SIZE)) != -1) {
baos.write(buffer, 0, bytesRead);
}
byte[] classData = baos.toByteArray();
return defineClassFromData(container, classData, classname);
}
/**
* Searches for and load a class on the classpath of this class loader.
*
* @param name The name of the class to be loaded. Must not be
* <code>null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
public Class findClass(String name) throws ClassNotFoundException {
log("Finding class " + name, Project.MSG_DEBUG);
return findClassInComponents(name);
}
/**
* Indicate if the given file is in this loader's path
*
* @param component the file which is to be checked
*
* @return true if the file is in the class path
*/
protected boolean isInPath(File component) {
for (Enumeration e = pathComponents.elements(); e.hasMoreElements();) {
File pathComponent = (File) e.nextElement();
if (pathComponent.equals(component)) {
return true;
}
}
return false;
}
/**
* Finds a class on the given classpath.
*
* @param name The name of the class to be loaded. Must not be
* <code>null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
private Class findClassInComponents(String name)
throws ClassNotFoundException {
// we need to search the components of the path to see if
// we can find the class we want.
InputStream stream = null;
String classFilename = getClassFilename(name);
try {
Enumeration e = pathComponents.elements();
while (e.hasMoreElements()) {
File pathComponent = (File) e.nextElement();
try {
stream = getResourceStream(pathComponent, classFilename);
if (stream != null) {
log("Loaded from " + pathComponent + " "
+ classFilename, Project.MSG_DEBUG);
return getClassFromStream(stream, name, pathComponent);
}
} catch (SecurityException se) {
throw se;
} catch (IOException ioe) {
// ioe.printStackTrace();
log("Exception reading component " + pathComponent
+ " (reason: " + ioe.getMessage() + ")",
Project.MSG_VERBOSE);
}
}
throw new ClassNotFoundException(name);
} finally {
try {
if (stream != null) {
stream.close();
}
} catch (IOException e) {
//ignore
}
}
}
/**
* Finds a system class (which should be loaded from the same classloader
* as the Ant core).
*
* For JDK 1.1 compatibility, this uses the findSystemClass method if
* no parent classloader has been specified.
*
* @param name The name of the class to be loaded.
* Must not be <code>null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
private Class findBaseClass(String name) throws ClassNotFoundException {
if (parent == null) {
return findSystemClass(name);
} else {
return parent.loadClass(name);
}
}
/**
* Cleans up any resources held by this classloader. Any open archive
* files are closed.
*/
public synchronized void cleanup() {
for (Enumeration e = zipFiles.elements(); e.hasMoreElements();) {
ZipFile zipFile = (ZipFile) e.nextElement();
try {
zipFile.close();
} catch (IOException ioe) {
// ignore
}
}
zipFiles = new Hashtable();
if (project != null) {
project.removeBuildListener(this);
}
project = null;
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the buildStarted event
*/
public void buildStarted(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Cleans up any resources held by this classloader at the end
* of a build.
*
* @param event the buildFinished event
*/
public void buildFinished(BuildEvent event) {
cleanup();
}
/**
* Cleans up any resources held by this classloader at the end of
* a subbuild if it has been created for the subbuild's project
* instance.
*
* @param event the buildFinished event
*
* @since Ant 1.6.2
*/
public void subBuildFinished(BuildEvent event) {
if (event.getProject() == project) {
cleanup();
}
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the buildStarted event
*
* @since Ant 1.6.2
*/
public void subBuildStarted(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the targetStarted event
*/
public void targetStarted(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the targetFinished event
*/
public void targetFinished(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the taskStarted event
*/
public void taskStarted(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the taskFinished event
*/
public void taskFinished(BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the messageLogged event
*/
public void messageLogged(BuildEvent event) {
// Not significant for the class loader.
}
/**
* add any libraries that come with different java versions
* here
*/
public void addJavaLibraries() {
Vector packages = JavaEnvUtils.getJrePackages();
Enumeration e = packages.elements();
while (e.hasMoreElements()) {
String packageName = (String) e.nextElement();
addSystemPackageRoot(packageName);
}
}
/**
* Returns a <code>String representing this loader.
* @return the path that this classloader has.
*/
public String toString() {
return "AntClassLoader[" + getClasspath() + "]";
}
}
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