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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
* buffered = new ArrayList();
/**
* private buffer for console input pipe.
*/
private List consbuffer = new ArrayList();
/**
* {@inheritDoc}
*/
public final void init(PeerGroup pg, ID assignedID, Advertisement impl) {
setGroup(pg);
setAssignedID(assignedID);
setImplAdvertisement(impl);
started = true;
}
/**
* {@inheritDoc}
*/
public void stopApp() {
stopped = true;
}
/**
* Return a String containing a single line description of the function of
* this ShellApp.
*/
public String getDescription() {
return "No description available for this ShellApp";
}
/**
* Print to the stdout a full description of the functionality of this
* Shell command.
*/
public void help() {
println("No help available for this ShellApp");
}
// Accessor Methods
/**
* Return the group in which this ShellApp is executing. Most ShellApps
* should instead use the value of the "stdgroup" environment variable.
*
* @return the current peer group.
*/
protected PeerGroup getGroup() {
return group;
}
/**
* Set the group will be the default group for this ShellApp. Most ShellApps
* should instead use the value of the "stdgroup" environment variable.
*/
private PeerGroup setGroup(PeerGroup g) {
PeerGroup old = group;
group = g;
return old;
}
/**
* Return the assignedID for this ShellApp if any.
*
* @return the assigned ID for this ShellApp or null if none
* was specified.
*/
protected final ID getAssignedID() {
return this.id;
}
/**
* Set the assignedID for this ShellApp
*
* @param id The assigned ID for this application
*/
private void setAssignedID(ID id) {
this.id = id;
}
/**
* Return the implementation advertisement for this ShellApp, if any.
*
* @return implementation Advertisement for this ShellApp or null
* if none was specified.
*/
protected final Advertisement getImplAdvertisement() {
return this.implAdv;
}
/**
* Sets the implementation advertisement for this ShellApp.
*
* @param adv The implementation advertisement for this ShellApp.
*/
private Advertisement setImplAdvertisement(Advertisement adv) {
Advertisement old = this.implAdv;
this.implAdv = adv;
return old;
}
/**
* Return a modifiable instance of this ShellApp's environment.
*
* @return This ShellApp's environment.
*/
protected final ShellEnv getEnv() {
return env;
}
/**
* Sets this ShellApp's environment.
*
* @return The environment for this ShellApp to use.
*/
protected final ShellEnv setEnv(ShellEnv e) {
ShellEnv old = env;
env = e;
return old;
}
protected final Thread setJoinedThread(Thread dependsOn) {
Thread old = this.dependsOn;
this.dependsOn = dependsOn;
return old;
}
/**
* Return the standard input pipe.
*
* @return the standard input pipe.
*/
protected final InputPipe getInputPipe() {
return inputPipe;
}
/**
* Set the standard input pipe to the provided pipe. The previous pipe is
* returned.
*
* @param ip the new standard input pipe.
* @return the old standard input pipe.
*/
protected final InputPipe setInputPipe(InputPipe ip) {
InputPipe old = inputPipe;
inputPipe = ip;
buffered.clear();
return old;
}
/**
* Return the standard output pipe.
*
* @return the standard output pipe.
*/
protected final OutputPipe getOutputPipe() {
return outputPipe;
}
/**
* Set the standard output pipe to the provided pipe. The previous pipe is
* returned.
*
* @param op the new standard output pipe.
* @return the old standard output pipe.
*/
protected final OutputPipe setOutputPipe(OutputPipe op) {
OutputPipe old = outputPipe;
outputPipe = op;
return old;
}
/**
* Return the console input pipe.
*
* @return the console input pipe.
*/
protected final InputPipe getInputConsPipe() {
return consin;
}
/**
* Set the console input pipe to the provided pipe. The previous pipe is
* returned.
*
* @param ip the new input output pipe.
* @return the old input output pipe.
*/
protected final InputPipe setInputConsPipe(InputPipe ip) {
InputPipe old = consin;
consin = ip;
consbuffer.clear();
return old;
}
/**
* Return the console output pipe.
*
* @return the console output pipe.
*/
protected final OutputPipe getOutputConsPipe() {
return consout;
}
/**
* Set the console output pipe to the provided pipe. The previous pipe is
* returned.
*
* @param op the new console output pipe.
* @return the old console output pipe.
*/
protected final OutputPipe setOutputConsPipe(OutputPipe op) {
OutputPipe old = consout;
consout = op;
return old;
}
/**
* Return the name of the environment into which this ShellApp should
* return any environment variable result.
*
* @return the name of the environment variable or null if no name has been
* set.
*/
protected final String getReturnVariable() {
return returnVarName;
}
/**
* Set the name of the environment into which this ShellApp should
* return any environment variable result.
*
* @param varName name of the environment variable.
*/
protected final void setReturnVariable(String varName) {
returnVarName = varName;
}
// IO Operations
/**
* Print to standard output
*
* @param line the line to print
*/
protected final void print(String line) {
if (null == outputPipe) {
return;
}
pipePrint(outputPipe, line);
}
/**
* Print to standard output appending a newline.
*
* @param line the line to print
*/
protected final void println(String line) {
if (null == outputPipe) {
return;
}
pipePrintln(outputPipe, line);
}
/**
* Poll for input on standard input.
*
* @return an input line or null if no input is available.
*/
protected final String pollInput() throws IOException {
if (null == inputPipe) {
return null;
}
if (inputPipe == consin)
return consPollInput();
else
return pipePollInput(inputPipe, buffered);
}
/**
* Wait for input on standard input.
*
* @return an input line or null if standard input has been
* closed.
*/
protected final String waitForInput() throws IOException {
if (null == inputPipe) {
return null;
}
if (inputPipe == consin)
return consWaitForInput();
else
return pipeWaitForInput(inputPipe, buffered, true);
}
/**
* Print to the console output.
*
* @param line the line to print
*/
protected final void consprint(String line) {
if (null == consout) {
return;
}
pipePrint(consout, line);
}
/**
* Print to console output appending a newline.
*
* @param line the line to print
*/
protected final void consprintln(String line) {
if (null == consout) {
return;
}
pipePrintln(consout, line);
}
/**
* Poll for input on console input.
*
* @return an input line or null if no input is available.
*/
protected final String consPollInput() throws IOException {
if (null == consin) {
return null;
}
return pipePollInput(consin, consbuffer);
}
/**
* Wait for input on console input.
*
* @return an input line or null if standard input has been
* closed.
*/
protected final String consWaitForInput() throws IOException {
if (null == consin) {
return null;
}
String msg = pipeWaitForInput(consin, consbuffer, false);
// create an EOT
if (msg != null) {
if (-1 != msg.indexOf('\u0004')) {
msg = null;
}
}
return msg;
}
protected final String getCmdShortName() {
return getCmdShortName(this.getClass());
}
public static String getCmdShortName(Class clas) {
String cmdClass = clas.getName();
String cmdName;
int lastDot = cmdClass.lastIndexOf(".");
if (-1 != lastDot) {
int secondLast = cmdClass.lastIndexOf(".", lastDot - 1);
String cmdPackage = "";
if (-1 != secondLast) {
cmdPackage = cmdClass.substring(secondLast + 1, lastDot);
}
cmdName = cmdClass.substring(lastDot + 1);
if (!cmdName.equals(cmdPackage)) {
cmdName = cmdPackage + "." + cmdName;
}
} else {
cmdName = cmdClass;
}
return cmdName;
}
/**
* print a message from the specified class on the specified pipe.
*
* @param clas the class which is printing the message
* @param consout the pipe on which to print the message
* @param message the message to print.
*/
public static void consoleMessage(Class clas, OutputPipe consout, String message) {
pipePrintln(consout, "# " + getCmdShortName(clas) + " - " + message);
}
/**
* Print a message on the console. The message will identify this ShellApp
* as the source of the message.
*
* @param message The message to print.
*/
protected final void consoleMessage(String message) {
consoleMessage(getClass(), consout, message);
}
/**
* Print a stack trace to the console with the specified annotation. The
* message will identify this ShellApp as the source of the exception.
*
* @param clas the class which is printing the message
* @param consout the pipe on which to print the message
* @param annotation Explanation or annotation for the stack trace.
* @param failure the stack trace.
*/
public static void printStackTrace(Class clas, OutputPipe consout, String annotation, Throwable failure) {
consoleMessage(clas, consout, annotation);
StringWriter theStackTrace = new StringWriter();
failure.printStackTrace(new PrintWriter(theStackTrace));
pipePrintln(consout, theStackTrace.toString());
}
/**
* Print a stack trace to the console with the specified annotation. The
* message will identify this ShellApp as the source of the exception.
*
* @param annotation Explanation or annotation for the stack trace.
* @param failure the stack trace.
*/
protected final void printStackTrace(String annotation, Throwable failure) {
printStackTrace(getClass(), consout, annotation, failure);
}
/**
* Load a shell application.
*
* @param returnvar The env variable in which the command should put its result.
* @param appName The name of the application to load.
* @param env The enviroment to use.
*/
protected ShellApp loadApp(String returnvar, String appName, ShellEnv env) {
ShellApp app;
try {
app = new ShellCmds(env).getInstance(appName);
} catch (Exception failed) {
printStackTrace("Exception in command : " + appName, failed);
return null;
}
if (null == app) {
return null;
}
// Set up the default environment and pipes
app.setEnv(env);
app.setJoinedThread(dependsOn);
ShellObject obj = env.get("consin");
if (null != obj) {
app.setInputConsPipe((InputPipe) obj.getObject());
}
obj = env.get("consout");
if (null != obj) {
app.setOutputConsPipe((OutputPipe) obj.getObject());
}
obj = env.get("stdin");
if (null != obj) {
app.setInputPipe((InputPipe) obj.getObject());
}
obj = env.get("stdout");
if (null != obj) {
app.setOutputPipe((OutputPipe) obj.getObject());
}
// Set the variable name for the return value (if any).
app.setReturnVariable(returnvar);
// now init it!
app.init((PeerGroup) env.get("stdgroup").getObject(), null, null);
return app;
}
/**
* Load and run a shell application.
*
* @param returnvar The env variable in which the command should put its result.
* @param appName The name of the application to load.
* @param env The enviroment to use.
*/
protected int exec(String returnvar, String appName, String[] args, ShellEnv env) {
ShellApp app = loadApp(returnvar, appName, env);
if (null == app) {
consoleMessage("Could not load application : " + appName);
return ShellApp.appMiscError;
}
return exec(app, args);
}
/**
* Run a loaded shell Application.
*
* @param app the application
* @param args arguments for the application.
*/
protected int exec(ShellApp app, String[] args) {
try {
// start the app
int result = app.startApp(args);
if (ShellApp.appSpawned != result) {
if ((ShellApp.appNoError != result) && (getEnv().contains("echo"))) {
consoleMessage("'" + app + "' returned error code : " + result);
}
app.stopApp();
}
return result;
} catch (Throwable e) {
printStackTrace("Exception in command : " + app, e);
return ShellApp.appMiscError;
}
}
// Private implementations
/**
* print to the specified pipe.
*
* @param pipe The destination pipe.
* @param line The text to print.
*/
public static void pipePrint(OutputPipe pipe, String line) {
if (null == pipe) {
return;
}
//Create a message off this string.
try {
Message msg = new Message();
MessageElement elem = new StringMessageElement("ShellOutputPipe", line, null);
msg.addMessageElement(elem);
pipe.send(msg);
} catch (IOException failure) {
failure.printStackTrace();
}
}
/**
* print to the specified pipe appending a newline after text.
*
* @param pipe The destination pipe.
* @param line The text to print.
*/
public static void pipePrintln(OutputPipe pipe, String line) {
pipePrint(pipe, line + "\n");
}
/*
* Return a string containing one line of input from the specified pipe.
*
* @param input the pipe to poll.
* @param lineBuffer a vector containing buffered lines associated with
* this pipe. If not present then it is VERY LIKELY YOU WILL LOSE MESSAGES.
* @return String containing the new line or null if no line was available.
* @throws IOException if the input pipe somehow becomes uninitialized.
*/
protected String pipePollInput(InputPipe input, List lineBuffer) throws IOException {
boolean onePoll = false;
do {
if (null != lineBuffer) {
// Check in the buffer first
synchronized (lineBuffer) {
if (!lineBuffer.isEmpty()) {
try {
return lineBuffer.remove(0);
} catch (Exception e) {
// This is a very strange case, but if that happens, let just
// wait for a message on the InputPipe.
}
}
}
}
if (input == null) {
throw new IOException("Input pipe null");
}
if (onePoll) {
return null;
}
Message msg = null;
try {
msg = input.poll(1000);
} catch (InterruptedException woken) {
Thread.interrupted();
}
// no message was waiting.
if (null == msg) {
return null;
}
onePoll = true;
// Get all the chunks of data in the message
Iterator elems = msg.getMessageElementsOfNamespace(null);
while (elems.hasNext()) {
Reader plainReader = null;
BufferedReader inputReader = null;
try {
MessageElement elem = elems.next();
elems.remove();
String name = elem.getElementName();
// because of pipe redirection we accept both input and
// and output elements.
if (!name.equals("ShellInputPipe") && !name.equals("ShellOutputPipe")) {
continue;
}
if (elem instanceof TextMessageElement) {
plainReader = ((TextMessageElement) elem).getReader();
} else {
InputStream inputStream = elem.getStream();
plainReader = new InputStreamReader(inputStream);
}
inputReader = new BufferedReader(plainReader);
do {
String command = inputReader.readLine();
if (null != command)
if (null != lineBuffer)
synchronized (lineBuffer) {
lineBuffer.add(command);
}
else
return command;
else
break;
} while (true);
} catch (Throwable e) {
e.printStackTrace();
} finally {
try {
if (null != plainReader) {
plainReader.close();
}
} catch (IOException ignored) {
//ignored
}
try {
if (null != inputReader) {
inputReader.close();
}
} catch (IOException ignored) {
//ignored
}
}
}
msg.clear();
} while (true);
}
private String pipeWaitForInput(InputPipe input, List lineBuffer, boolean join) throws IOException {
String msg;
while (true) {
msg = pipePollInput(input, lineBuffer);
if ((null != msg) || stopped)
break;
if (join && ((null == dependsOn) || (!dependsOn.isAlive())))
break;
}
return msg;
}
}