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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package test.java.awt.regtesthelpers.process;
import java.io.*;
/**
* This class is created to solve interprocess communication problems.
* When you need to write a regression test which should verify inter jvm
* behavior such as DnD data transfer, Clipboard data transfer, focus
* transfer etc., you could use the next scenario:
*
* 1. Write an implementation for the parent JVM, using applet test.
* 2. Write an implementation for the child JVM or native application, using
* main() function.
* 3. Execute child process using ProcessCommunicator.executeChildProcess()
* method.
* 4. You can decide whether the test is passed on the basis of
* ProcessResults class data.
*
* Note: The class is not thread safe. You should access its methods only from
* the same thread.
*/
public class ProcessCommunicator {
private static final String javaHome = System.getProperty("java.home", "");
private static final String javaPath = javaHome + File.separator + "bin" +
File.separator + "java ";
private static String command = "";
private static volatile Process process;
private ProcessCommunicator() {}
/**
* The same as {#link #executeChildProcess(Class,String)} except
* the {@code classPathArgument} parameter. The class path
* parameter is for the debug purposes
*
* @param classToExecute is passed to the child JVM
* @param classPathArguments class path for the child JVM
* @param args arguments that will be passed to the executed class
* @return results of the executed {@code Process}
*/
public static ProcessResults executeChildProcess(final Class classToExecute,
final String classPathArguments, final String [] args)
{
try {
String command = buildCommand(classToExecute, classPathArguments, args);
process = Runtime.getRuntime().exec(command);
return doWaitFor(process);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Executes child {code Process}
*
* @param classToExecute class to be executed as a child java process
* @param args args to be passed in to the child process
* @return results of the executed {@code Process}
*/
public static ProcessResults executeChildProcess(final Class classToExecute,
final String [] args)
{
return executeChildProcess(classToExecute, System.getProperty("java.class.path"), args);
}
/**
* Waits for a process and return its results.
* This is a workaround for {@code Process.waitFor()} never returning.
*
* @return results of the executed {@code Process}
*/
public static ProcessResults doWaitFor(final Process p) {
ProcessResults pres = new ProcessResults();
final InputStream in;
final InputStream err;
try {
in = p.getInputStream();
err = p.getErrorStream();
boolean finished = false;
while (!finished) {
try {
while (in.available() > 0) {
pres.appendToStdOut((char)in.read());
}
while (err.available() > 0) {
pres.appendToStdErr((char)err.read());
}
// Ask the process for its exitValue. If the process
// is not finished, an IllegalThreadStateException
// is thrown. If it is finished, we fall through and
// the variable finished is set to true.
pres.setExitValue(p.exitValue());
finished = true;
}
catch (IllegalThreadStateException e) {
// Process is not finished yet;
// Sleep a little to save on CPU cycles
Thread.currentThread().sleep(500);
}
}
if (in != null) in.close();
if (err != null) err.close();
}
catch (Throwable e) {
System.err.println("doWaitFor(): unexpected exception");
e.printStackTrace();
}
return pres;
}
/**
* Builds command on the basis of the passed class name,
* class path and arguments.
*
* @param classToExecute with class will be executed in the new JVM
* @param classPathArguments java class path (only for test purposes)
* @param args arguments for the new application. This could be used
* to pass some information from the parent to child JVM.
* @return command to execute the {@code Process}
*/
private static String buildCommand(final Class classToExecute,
final String classPathArguments, final String [] args)
{
StringBuilder commandBuilder = new StringBuilder();
commandBuilder.append(javaPath).append(" ");
commandBuilder.append("-cp ").append(System.getProperty("test.classes", ".")).append(File.pathSeparatorChar);
if (classPathArguments.trim().length() > 0) {
commandBuilder.append(classPathArguments).append(" ");
}
commandBuilder.append(" ");
commandBuilder.append(classToExecute.getName());
for (String argument:args) {
commandBuilder.append(" ").append(argument);
}
command = commandBuilder.toString();
return command;
}
/**
* Could be used for the debug purposes.
*
* @return command that was build to execute the child process
*/
public static String getExecutionCommand () {
return command;
}
/**
* Terminates the process created by {@code executeChildProcess} methods.
*/
public static void destroyProcess() {
if (process != null) {
if (process.isAlive()) {
process.destroy();
}
process = null;
}
}
}