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The basic runtime tools and interfaces for intarsys components.
/*
* Copyright (c) 2007, intarsys consulting GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of intarsys nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.intarsys.tools.reflect;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* Tool class to enhance the reflective capabilities about classes.
*/
public class ClassTools {
/** The string used to separate paths in a list of path definitions */
private static final String PATH_SEPARATOR = System
.getProperty("path.separator");
/**
* Create a list of all classes that are available from classPath.
*
*
* Be aware that the classes are loaded and so any static code is executed.
*
*
* @param classPath
* The classpath to inspect
*
* @return A list of all classes that are available from classPath.
*
* @throws IOException
*/
public static List collectClasses(String classPath) throws IOException {
List classNames = collectClassNames(classPath);
ClassLoader loader = createClassLoader(classPath);
List classes = new ArrayList();
for (Iterator it = classNames.iterator(); it.hasNext();) {
String className = (String) it.next();
try {
classes.add(loader.loadClass(className));
} catch (ClassNotFoundException e) {
// ignore
}
}
return classes;
}
/**
* Create a list of class names in dot notation that can be found in the
* classPath.
*
* @param classPath
* The classpath to inspect
*
* @return A list of class names in dot notation that can be found in the
* classPath.
*
* @throws IOException
*/
public static List collectClassNames(String classPath) throws IOException {
List classnames = new ArrayList();
StringTokenizer path = new StringTokenizer(classPath, PATH_SEPARATOR);
int pathCount = path.countTokens();
for (int ii = 0; ii < pathCount; ii++) {
String currentName = path.nextToken();
File currentFile = new File(currentName);
if (currentFile.isFile()) {
extractClassNamesFromJar(classnames, currentFile);
} else {
extractClassNamesFromDir(classnames, currentFile, "");
}
}
return classnames;
}
public static Class createClass(String className,
Class expectedClass, ClassLoader classLoader)
throws ObjectCreationException {
if (className == null) {
throw new ObjectCreationException("class name missing");
}
className = className.trim();
try {
if (classLoader == null) {
classLoader = Thread.currentThread().getContextClassLoader();
}
if (classLoader == null) {
// as good as any
classLoader = expectedClass.getClassLoader();
}
Class clazz = Class.forName(className, false, classLoader);
if (expectedClass != null && !expectedClass.isAssignableFrom(clazz)) {
throw new ObjectCreationException("class '" + clazz.getName()
+ "' not compatible with expected type '"
+ expectedClass + "'");
}
return clazz;
} catch (ClassNotFoundException e) {
throw new ObjectCreationException("class '" + className
+ "' not found", e);
} catch (Throwable e) {
// Class.forName may throw Error when class name mismatched !!
throw new ObjectCreationException("class '" + className
+ "' not found", e);
}
}
/**
* Create a new ClassLoader on the specified classpath
*
* @param classPath
* The classpath we want to load from.
*
* @return A new ClassLoader on the specified classpath
*/
public static ClassLoader createClassLoader(String classPath) {
URL[] allURLs = null;
StringTokenizer path = new StringTokenizer(classPath, PATH_SEPARATOR);
int i = path.countTokens();
allURLs = new URL[i + 1];
for (int ii = 0; ii < i; ii++) {
String currentPath = path.nextToken();
try {
URL url = new URL("file", "", currentPath);
allURLs[ii] = url;
} catch (MalformedURLException e) {
// should not happen
}
}
ClassLoader loader = URLClassLoader.newInstance(allURLs);
return loader;
}
/**
* Create a list of all classes "current" and its subdirectories.
*
* @param result
* The collection that is filled with new classnames
* @param currentFile
* The directory/file under inspection
* @param relativePath
* The path extending from the initial root we are currently
* inspecting.
*
* @throws IOException
*/
protected static void extractClassNamesFromDir(List result,
File currentFile, String relativePath) throws IOException {
if (currentFile.isFile()) {
String filename = currentFile.getName();
if (filename.endsWith(".class")) {
String className = filename.substring(0, filename.length() - 6);
result.add(relativePath + className);
}
} else {
String[] allFiles = currentFile.list();
if (allFiles == null) {
throw new IOException("error creating directory listing for "
+ currentFile.getAbsolutePath());
}
for (int i = 0; i < allFiles.length; i++) {
File child = new File(currentFile, allFiles[i]);
extractClassNamesFromDir(result, child, relativePath
+ allFiles[i] + ".");
}
}
}
/**
* Create a list of all ".class" entries in the jar file.
*
* @param result
* The collection that is filled with new classnames
* @param file
* The jar file we are inspecting.
*
* @throws IOException
*/
protected static void extractClassNamesFromJar(List result, File file)
throws IOException {
JarFile jar = null;
try {
jar = new JarFile(file);
Enumeration entries = jar.entries();
while (entries.hasMoreElements()) {
JarEntry entry = (JarEntry) entries.nextElement();
String entryName = entry.getName();
if (entryName.endsWith(".class")) {
String className = entryName.substring(0, entryName
.length() - 6);
className = className.replace('/', '.');
result.add(className);
}
}
} finally {
if (jar != null) {
jar.close();
}
}
}
static public String getPackageName(Class clazz) {
String name = clazz.getName();
int pos = name.lastIndexOf('.');
if (pos >= 0) {
return name.substring(0, pos);
}
return name;
}
static public String getUnqualifiedName(Class clazz) {
String name = clazz.getName();
int pos = name.lastIndexOf('.');
if (pos >= 0) {
return name.substring(pos + 1);
}
return name;
}
/**
*
*/
private ClassTools() {
super();
}
}
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