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The JXTA Shell is a sample application that demonstrates key concepts
of JXTA JXSE. The JXTA Shell enables users to interact with the JXTA
platform through a command-line interpreter. Much like the UNIX® shell,
the JXTA Shell is useful for accessing and managing core platform objects
(peers, groups, pipes), debugging communications problems, checking the
status of peers and/or peer groups, and communicating with other JXTA
services and applications. As in UNIX®, the JXTA shell allows users to
"pipe" shell commands together connecting commands "on-the-fly." Pipes
in Project JXTA are useful for collecting information at one peer and
perhaps processing the command at another.
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/*
* Copyright (c) 2001 Sun Microsystems, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Sun Microsystems, Inc. for Project JXTA."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact Project JXTA at http://www.jxta.org.
*
* 5. Products derived from this software may not be called "JXTA",
* nor may "JXTA" appear in their name, without prior written
* permission of Sun.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 SUN MICROSYSTEMS OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of Project JXTA. For more
* information on Project JXTA, please see
* ...
*
* Whenever a ShellApp needs access to the Shell commands this class should be used.
* For example to get all available Shell commands use the following code:
*
* ShellCmds cmds = new ShellCmds((ShellApp)this);
* String[] cmdList = cmds.list();
*
* To instantiate a command you could use following code:
*
* // Instantiate the 'man' command.
* ShellApp app = cmds.getInstance("man");
* // Now set the group and the input and output pipes if neccessary.
* ...
* // For example we want to print the short description of the app.
* println(app.getDescription());
*
*/
public final class ShellCmds {
/**
* For debugging purposes.
*/
private static final java.util.logging.Logger LOG = java.util.logging.Logger.getLogger(ShellCmds.class.getName());
/**
* Name of environment variable.
*/
public static final String INST_JARS = "instjars";
/**
* Char used to separate paths.
*/
public static final String PATH_SEPARATOR = System.getProperty("path.separator");
static final String BIN_PACKAGE = "net.jxta.impl.shell.bin";
static final String BIN_PATH = "net/jxta/impl/shell/bin/";
static final int BIN_PATH_LEN = BIN_PATH.length();
/**
* Reference to the ShellApp that instantiated this class.
*/
private final ShellEnv env;
/**
* Initializes a newly created ShellCmds object with a reference to the instantiating ShellApp.
* This reference will be used to obtain its current ShellEnv object which serves for reading
* and storing the INST_JARS environment variable.
*
* @param env the environment to use.
*/
public ShellCmds(ShellEnv env) {
this.env = env;
}
/**
* Static method to extract the list of paths out of a String. The format of the String is:
* ...
* Only correct paths are added to the later returned list.
*
* @param pathList the String the paths will be extracted from.
* @return an array of all valid paths. If the given parameter contains no path or none
* of the given paths is valid then an empty list is returned.
*/
public static URL[] parseClassPath(String pathList) {
List pathURLS = new ArrayList();
StringTokenizer tok = new StringTokenizer(pathList, PATH_SEPARATOR, false);
while (tok.hasMoreTokens()) {
String fileName = tok.nextToken();
File file = new File(fileName);
try {
pathURLS.add(file.toURI().toURL());
} catch (MalformedURLException bad) {
//ignored
}
}
return pathURLS.toArray(new URL[pathURLS.size()]);
}
/**
* Static method to encode a list of paths into its corresponding String representation.
* The format of the String is: ...
*
* @param pathList the list of paths to be encoded.
* @return a String representation of the given list.
*/
public static String encodeInstJars(List pathList) {
StringBuilder buf = new StringBuilder();
for (int i = 0, size = pathList.size(); i < size; i++) {
buf.append(pathList.get(i));
if (i < size - 1)
buf.append(PATH_SEPARATOR);
}
return buf.toString();
}
/**
* Stores the String representation of the given list of paths in the environment
* of the ShellApp.
*
* @param pathList list of paths to be stored in the environment of the ShellApp.
*/
public void setInstJars(List pathList) {
// Convert list into its corresponding String representation,
String instJars = encodeInstJars(pathList);
// and set the new value of environment variable INST_JARS.
env.add(INST_JARS, new ShellObject("Installed Jar Files", instJars));
}
/**
* Retrieves the list of paths encoded as a String from the ShellApp's environment.
*
* @return a list of path objects.
*/
public URL[] getInstJars() {
if (env.contains(INST_JARS)) {
// If environment variable INST_JARS already exists, then
// get environment variable INST_JARS, and
// extract zip-files and directories and construct a list containing them.
String instJars = (String) env.get(INST_JARS).getObject();
return parseClassPath(instJars);
} else {
// else return an empty list.
return new URL[0];
}
}
/**
* Returns an array of all available Shell commands.
*
* The current implementation tries to locate commands on the classpath
* pf the classloader
*
* @return an array of the names of all the available shell commands.
*/
public String[] list() {
List list = cmdlist();
return list.toArray(new String[list.size()]);
}
/**
* Returns a list of all available Shell commands.
*
* The current implementation tries to locate commands on the classpath
* pf the classloader
*
* @return list of the names of all the available shell commands.
*/
public List cmdlist() {
List classpath = new ArrayList();
// Retrieve the list of paths representing jar-files.
classpath.addAll(Arrays.asList(parseClassPath(System.getProperty("java.class.path"))));
classpath.addAll(Arrays.asList(getInstJars()));
// Initialize a ClassLoader that also searches jar-files for classes.
URLClassLoader scl = new URLClassLoader(new URL[0], this.getClass().getClassLoader());
List cmds = new ArrayList();
classpath.addAll(Arrays.asList(scl.getURLs()));
for (URL aURL : classpath) {
try {
if (aURL.toString().endsWith("/")) {
// A Directory
if (!"file".equalsIgnoreCase(aURL.getProtocol())) {
continue;
}
File dir = new File(new File(aURL.getPath()), BIN_PATH);
if (dir.exists()) {
File[] dirCmds = dir.listFiles();
for (File file : Arrays.asList(dirCmds)) {
try {
if (file.isDirectory()) {
File[] someCmds = file.listFiles();
for (File file1 : Arrays.asList(someCmds)) {
if (file1.getName().endsWith(".class")) {
String filename = file1.getName();
filename = filename.substring(0, filename.length() - 6);
if (file.getName().equals(filename)) {
if (null != getInstance(filename)) {
cmds.add(filename);
}
} else {
if (null != getInstance(file.getName() + "." + filename)) {
cmds.add(file.getName() + "." + filename);
}
}
}
}
}
} catch (Exception ignored) {
//ignored
}
}
}
} else {
// A class or Jar
String entryName = aURL.getPath();
if (entryName.endsWith(".class")) {
// A class file
entryName = entryName.substring(0, entryName.length() - 6);
int cmdPath = entryName.indexOf(BIN_PATH);
if (-1 != cmdPath) {
String cmdName = entryName.substring(cmdPath + BIN_PATH_LEN);
cmds.add(cmdName);
}
} else if (entryName.endsWith(".jar")) {
// A jar file
Enumeration eachEntry;
if ("jar".equalsIgnoreCase(aURL.getProtocol())) {
JarURLConnection jar = (JarURLConnection) aURL.openConnection();
JarFile jarfile = jar.getJarFile();
eachEntry = jarfile.entries();
} else {
URLConnection jar = aURL.openConnection();
JarInputStream jis = new JarInputStream(jar.getInputStream());
List allEntries = new ArrayList();
JarEntry anEntry = jis.getNextJarEntry();
while (null != anEntry) {
allEntries.add(anEntry);
anEntry = jis.getNextJarEntry();
}
eachEntry = Collections.enumeration(allEntries);
}
while (eachEntry.hasMoreElements()) {
JarEntry anEntry = eachEntry.nextElement();
entryName = anEntry.getName();
if (entryName.endsWith(".class")) {
entryName = entryName.substring(0, entryName.length() - 6);
int cmdPath = entryName.indexOf(BIN_PATH);
if (-1 != cmdPath) {
String leafPath = entryName.substring(cmdPath + BIN_PATH_LEN);
String pkgName = leafPath.substring(0, leafPath.indexOf('/'));
String cmdName = leafPath.substring(leafPath.indexOf('/') + 1);
if (pkgName.equals(cmdName)) {
cmds.add(cmdName);
} else {
cmds.add(pkgName + "." + cmdName);
}
}
}
}
} else {
// Unknown file
}
}
} catch (Exception failure) {
if (LOG.isLoggable(Level.WARNING)) {
LOG.log(Level.WARNING, " Failure processing : " + ((null != aURL) ? aURL.toString() : ""), failure);
}
}
}
Collections.sort(cmds);
return cmds;
}
/**
* Instantiates a given Command and returns its reference. For this purpose this implementation
* tries to load the class 'net.jxta.impl.shell.bin.pkg.cmd'. This class is then instantiated through
* the standard constructor. No other initialization is done, so the caller of this method should
* set the group, outputPipe, etc.
*
* @param cmd The command to execute. In the form "." .
* @return an instance of the specified Shell command.
*/
public ShellApp getInstance(String cmd) {
URL[] pathURLs = getInstJars();
// Initialize a ClassLoader that also searches jar-files for classes.
URLClassLoader scl = new URLClassLoader(pathURLs, this.getClass().getClassLoader());
// Make sure that the Context loader of the current thread
// is properly set, so if the shell commands creates its own
// thread, the Shell class loader will also be used.
Thread.currentThread().setContextClassLoader(scl);
// try just loading the class by name
Class appClass = null;
try {
appClass = (Class) scl.loadClass(cmd);
} catch (NoClassDefFoundError notFound) {
//ignored
} catch (ClassNotFoundException notFound) {
//ignored
}
if (null == appClass) {
String cmdPkg;
String cmdcmdName;
if (-1 == cmd.indexOf('.')) {
cmdPkg = cmd;
cmdcmdName = cmd;
} else {
cmdPkg = cmd.substring(0, cmd.lastIndexOf('.'));
cmdcmdName = cmd.substring(cmd.lastIndexOf('.') + 1);
}
String cmdclassName = BIN_PACKAGE + "." + cmdPkg + "." + cmdcmdName;
if (LOG.isLoggable(java.util.logging.Level.FINE))
LOG.finer("Loading command : " + cmdclassName);
// Load the class with the help of scl.
try {
appClass = (Class) Class.forName(cmdclassName, true, scl);
} catch (ClassNotFoundException failed) {
return null;
}
if (!ShellApp.class.isAssignableFrom(appClass)) {
return null;
}
try {
if (null == appClass.getConstructor()) {
// missing required constructor.
return null;
}
} catch (NoSuchMethodException missingConstructor) {
return null;
}
}
// Instantiate loaded command class and return it.
try {
ShellApp app = appClass.newInstance();
return app;
} catch (java.lang.InstantiationException failed) {
throw new UndeclaredThrowableException(failed);
} catch (java.lang.IllegalAccessException failed) {
return null;
}
}
}