/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.test.db;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Arrays;
import org.h2.test.utils.SelfDestructor;
import org.h2.util.Task;
import org.h2.util.StringUtils;
/**
* A task that is run as an external process. This class communicates over
* standard input / output with the process. The standard error stream of the
* process is directly send to the standard error stream of this process.
*/
public class TaskProcess {
private final TaskDef taskDef;
private Process process;
private BufferedReader reader;
private BufferedWriter writer;
/**
* Construct a new task process. The process is not started yet.
*
* @param taskDef the task
*/
public TaskProcess(TaskDef taskDef) {
this.taskDef = taskDef;
}
/**
* Start the task with the given arguments.
*
* @param args the arguments, or null
*/
public void start(String... args) {
try {
String selfDestruct = SelfDestructor.getPropertyString(60);
ArrayList<String> list = new ArrayList<String>();
list.add("java");
list.add(selfDestruct);
list.add("-cp");
list.add("bin" + File.pathSeparator + ".");
list.add(TaskDef.class.getName());
list.add(taskDef.getClass().getName());
if (args != null && args.length > 0) {
list.addAll(Arrays.asList(args));
}
String[] procDef = new String[list.size()];
list.toArray(procDef);
traceOperation("start: " + StringUtils.arrayCombine(procDef, ' '));
process = Runtime.getRuntime().exec(procDef);
copyInThread(process.getErrorStream(), System.err);
reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
writer = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
String line = reader.readLine();
if (line == null) {
throw new RuntimeException("No reply from process, command: " + StringUtils.arrayCombine(procDef, ' '));
} else if (line.startsWith("running")) {
traceOperation("got reply: " + line);
} else if (line.startsWith("init error")) {
throw new RuntimeException(line);
}
} catch (Throwable t) {
throw new RuntimeException("Error starting task", t);
}
}
private static void copyInThread(final InputStream in, final OutputStream out) {
new Task() {
public void call() throws IOException {
while (true) {
int x = in.read();
if (x < 0) {
return;
}
if (out != null) {
out.write(x);
}
}
}
}.execute();
}
/**
* Receive a message from the process over the standard output.
*
* @return the message
*/
public String receive() {
try {
return reader.readLine();
} catch (IOException e) {
throw new RuntimeException("Error reading", e);
}
}
/**
* Send a message to the process over the standard input.
*
* @param message the message
*/
public void send(String message) {
try {
writer.write(message + "\n");
writer.flush();
} catch (IOException e) {
throw new RuntimeException("Error writing " + message, e);
}
}
/**
* Kill the process if it still runs.
*/
public void destroy() {
process.destroy();
}
/**
* Trace the operation. Tracing is disabled by default.
*
* @param s the string to print
*/
private void traceOperation(String s) {
// ignore
}
}