org.apache.tools.ant.taskdefs.classloader.SimpleClassloaderUtil Maven / Gradle / Ivy
/*
* Copyright 2005 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.taskdefs.classloader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.apache.tools.ant.taskdefs.classloader.report.ClassloaderReporter;
/**
* Provides some utility methods for ClassloaderTask and ClassloaderReport.
* @since Ant1.7
*/
public final class SimpleClassloaderUtil implements ClassloaderUtil {
private static final int BUFFER_MULT = 50;
private static final ClassloaderUtil SINGLETON = new SimpleClassloaderUtil();
/**
* Gets the singleton instance of this implementation.
* @return The singleton instance of this implementation.
*/
public static ClassloaderUtil getClassLoaderUtil() {
return SINGLETON;
}
/**
* Indicates whether a classloader or it's delegation parents
* contains an entry.
* @param ctx The context.
* @param cl The classloader.
* @param url The entry as an url.
* @return True if the entry was found, false if not.
*/
public boolean containsEntry(ClassloaderContext ctx,
ClassLoader cl, String url) {
ArrayList errors = new ArrayList();
if (containsEntryDelegatedOrSelf(ctx, cl, url, errors)) {
return true;
}
if (errors.size() > 0) {
StringBuffer sb = new StringBuffer(BUFFER_MULT * (1 + errors.size()));
sb.append("Check for duplicate entries fails due to the following reason(s):");
for (Iterator i = errors.iterator(); i.hasNext();) {
sb.append("\n").append(i.next());
}
ctx.handleWarning(sb.toString());
}
return false;
}
/**
* Checks whether an url is in the classpath of a classloader or it's
* delegation hierarchy.
* NOTE: As of performance reasons, this method does not do the check in the
* loading order (parentloader - childloader).
*
* @param cl The classloader.
* @param url The url.
* @param errors A list of errors to report.
* @return true, if the classloader or one of it's implicite
* or explicite parents contains the url. false
* otherwise.
*/
private static boolean containsEntryDelegatedOrSelf(
ClassloaderContext ctx, ClassLoader cl, String url,
List errors) {
if (cl == null) {
URL[] urls = ctx.getUtil().getBootstrapClasspathURLs();
if (urls == null) {
errors.add("bootstrap classpath not investigatable");
return false;
}
for (int i = 0; i < urls.length; i++) {
if (urls[i].toString().equals(url)) {
return true;
}
}
return false;
}
if (containsEntrySelf(ctx, cl, url, errors)) {
return true;
}
ClassLoaderAdapter adapter = ctx.getUtil().findAdapter(ctx, cl, null,
errors, " parent of classloader "
+ cl.getClass().getModifiers(), "");
ClassLoader parent = null;
if (adapter != null) {
parent = adapter.getParent(cl);
if (parent == null) {
parent = adapter.getDefaultParent();
}
}
return containsEntryDelegatedOrSelf(ctx, parent, url, errors);
}
private static boolean containsEntrySelf(ClassloaderContext ctx,
ClassLoader cl, String url, List errors) {
ClassLoaderAdapter adapter = ctx.getUtil().findAdapter(ctx, cl,
ClassLoaderAdapterAction.GETPATH, errors,
"path for classloader " + cl.getClass().getName(), "");
if (adapter == null) {
return false;
}
String[] cp = adapter.getClasspath(ctx, cl, false);
if (cp == null) {
errors.add("path for classloader " + cl.getClass().getName()
+ " not investigatable (adapter retrieves no path)");
return false;
}
for (int i = 0; i < cp.length; i++) {
if (cp[i].equals(url)) {
return true;
}
}
return false;
}
/**
* Gets the adapter for the specified classloader and action.
* @param ctx The context.
* @param cl The classloader to get an adapter for.
* @param action The action to get an adapter for or null if
* the adapter is needed for common methods.
* @return The adapter.
* @throws ClassloaderAdapterException if no adapter can found.
*/
public ClassLoaderAdapter findAdapter(ClassloaderContext ctx,
ClassLoader cl, ClassLoaderAdapterAction action)
throws ClassloaderAdapterException {
ClassLoaderHandlerSet handlerSet = ctx.getHandlerSet();
if (handlerSet == null) {
throw new ClassloaderAdapterException(ClassloaderAdapterException.NO_HANDLERSET);
}
ClassLoaderHandler handler = handlerSet.getHandler(ctx, cl, action);
if (handler == null) {
throw new ClassloaderAdapterException(ClassloaderAdapterException.NO_HANDLER);
}
ClassLoaderAdapter adapter = handler.getAdapter(ctx);
if (adapter == null) {
throw new ClassloaderAdapterException(ClassloaderAdapterException.NO_ADAPTER);
}
return adapter;
}
/**
* Gets the adapter for the specified classloader and action.
* @param ctx The context.
* @param cl The classloader to get an adapter for.
* @param action The action to get an adapter for or null if
* the adapter is needed for common methods.
* @param to The reporter to report errors against.
* @param errPrefix A prefix for error messages.
* @param errSuffix A suffix for error messages.
* @return The adapter or null if an error occured.
*/
public ClassLoaderAdapter findAdapter(ClassloaderContext ctx,
ClassLoader cl, ClassLoaderAdapterAction action,
ClassloaderReporter to, String errPrefix, String errSuffix) {
try {
return findAdapter(ctx, cl, action);
} catch (ClassloaderAdapterException e) {
switch (e.getReason()) {
case ClassloaderAdapterException.NO_HANDLER:
to.reportError(errPrefix
+ " not investigatable (no Loaderhandler found)"
+ errSuffix);
break;
case ClassloaderAdapterException.NO_ADAPTER:
to.reportError(errPrefix
+ " not investigatable (Loaderhandler retrieves no adapter)"
+ errSuffix);
break;
default:
ctx.handleError(errPrefix
+ " not investigatable (no Loaderhandlerset)"
+ errSuffix, e);
}
}
return null;
}
/**
* Gets the adapter for the specified classloader and action.
* @param ctx The context.
* @param cl The classloader to get an adapter for.
* @param action The action to get an adapter for or null if
* the adapter is needed for common methods.
* @param errors A list to add a message if an error occurs.
* @param errPrefix A prefix for error messages.
* @param errSuffix A suffix for error messages.
* @return The adapter or null if an error occured.
*/
public ClassLoaderAdapter findAdapter(ClassloaderContext ctx,
ClassLoader cl, ClassLoaderAdapterAction action, List errors,
String errPrefix, String errSuffix) {
try {
return findAdapter(ctx, cl, action);
} catch (ClassloaderAdapterException e) {
switch (e.getReason()) {
case ClassloaderAdapterException.NO_HANDLER:
errors.add(errPrefix
+ " not investigatable (no Loaderhandler found)"
+ errSuffix);
break;
case ClassloaderAdapterException.NO_ADAPTER:
errors
.add(errPrefix
+ " not investigatable (Loaderhandler retrieves no adapter)"
+ errSuffix);
break;
default:
ctx.handleError(errPrefix
+ " not investigatable (no Loaderhandlerset)"
+ errSuffix, e);
}
}
return null;
}
/**
* Gets the Urls of the bootstrap classpath.
* @return The urls of the bootstrap classpath or null if they
* can not determined.
*/
public URL[] getBootstrapClasspathURLs() {
try {
Object urlClassPath = Class.forName("sun.misc.Launcher").getMethod(
"getBootstrapClassPath", null).invoke(null, null);
return (URL[]) urlClassPath.getClass().getMethod("getURLs", null)
.invoke(urlClassPath, null);
} catch (Exception e) {
return null;
}
}
private SimpleClassloaderUtil() {
super();
}
}
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