org.codehaus.mojo.javacc.ForkedJvm Maven / Gradle / Ivy
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Maven 3 Plugin for processing JavaCC grammar files.
package org.codehaus.mojo.javacc;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import java.io.File;
import java.net.URL;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.annotation.Nullable;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.cli.CommandLineUtils;
import org.codehaus.plexus.util.cli.Commandline;
import org.codehaus.plexus.util.cli.StreamConsumer;
/**
* Runs the main() method of some tool in a forked JVM.
*
* @author Benjamin Bentmann
* @version $Id: ForkedJvm.java 7758 2008-09-29 20:06:33Z bentmann $
* @see java
* - The Java Application Launcher
*/
class ForkedJvm
{
/**
* The consumer for System.out messages.
*/
private StreamConsumer systemOut;
/**
* The consumer for System.err messages.
*/
private StreamConsumer systemErr;
/**
* The executable used to fork the JVM.
*/
private final String executable;
/**
* The working directory for the forked JVM.
*/
private File workingDirectory;
/**
* The class path entries for the forked JVM, given as strings.
*/
private final Set m_aClassPathEntries = new LinkedHashSet <> ();
/**
* The qualified name of the class on which to invoke the main()
* method.
*/
private String mainClass;
/**
* The command line arguments to pass to the main() method, given
* as strings.
*/
private final List cmdLineArgs = new ArrayList <> ();
/**
* Creates a new configuration to fork a JVM.
*/
public ForkedJvm ()
{
this.executable = _getDefaultExecutable ();
}
/**
* Gets the absolute path to the JVM executable.
*
* @return The absolute path to the JVM executable.
*/
private static String _getDefaultExecutable ()
{
return System.getProperty ("java.home") + File.separator + "bin" + File.separator + "java";
}
/**
* Sets the working directory for the forked JVM.
*
* @param directory
* The working directory for the forked JVM, may be null
* to inherit the working directory of the current JVM.
*/
public void setWorkingDirectory (final File directory)
{
this.workingDirectory = directory;
}
/**
* Sets the stream consumer used to handle messages from
* System.out.
*
* @param consumer
* The stream consumer, may be null to discard the output.
*/
public void setSystemOut (final StreamConsumer consumer)
{
this.systemOut = consumer;
}
/**
* Sets the stream consumer used to handle messages from
* System.err.
*
* @param consumer
* The stream consumer, may be null to discard the output.
*/
public void setSystemErr (final StreamConsumer consumer)
{
this.systemErr = consumer;
}
/**
* Gets the class path for the forked JVM.
*
* @return The class path for the forked JVM.
*/
private String _getClassPath ()
{
return StringUtils.join (this.m_aClassPathEntries.iterator (), File.pathSeparator);
}
/**
* Adds the specified path to the class path of the forked JVM.
*
* @param path
* The path to add, may be null.
*/
public void addClassPathEntry (final String path)
{
if (path != null)
{
this.m_aClassPathEntries.add (path);
}
}
/**
* Adds the specified path to the class path of the forked JVM.
*
* @param path
* The path to add, may be null.
*/
public final void addClassPathEntry (@Nullable final File path)
{
if (path != null)
m_aClassPathEntries.add (path.getAbsolutePath ());
}
/**
* Adds the source JAR of the specified class/interface to the class path of
* the forked JVM.
*
* @param type
* The class/interface to add, may be null.
*/
public final void addClassPathEntry (final Class type)
{
addClassPathEntry (_getClassSource (type));
}
/**
* Gets the JAR file or directory that contains the specified class.
*
* @param type
* The class/interface to find, may be null.
* @return The absolute path to the class source location or null
* if unknown.
*/
private static File _getClassSource (final Class type)
{
if (type != null)
{
final String classResource = type.getName ().replace ('.', '/') + ".class";
return _getResourceSource (classResource, type.getClassLoader ());
}
return null;
}
/**
* Gets the JAR file or directory that contains the specified class.
*
* @param className
* The qualified name of the class/interface to find, may be
* null.
* @return The absolute path to the class source location or null
* if unknown.
*/
private static File _getClassSource (final String className)
{
if (className != null)
{
final String classResource = className.replace ('.', '/') + ".class";
return _getResourceSource (classResource, Thread.currentThread ().getContextClassLoader ());
}
return null;
}
/**
* Gets the JAR file or directory that contains the specified resource.
*
* @param resource
* The absolute name of the resource to find, may be null.
* @param loader
* The class loader to use for searching the resource, may be
* null.
* @return The absolute path to the resource location or null if
* unknown.
*/
@Nullable
private static File _getResourceSource (final String resource, final ClassLoader loader)
{
if (resource != null)
{
URL url;
if (loader != null)
{
url = loader.getResource (resource);
}
else
{
url = ClassLoader.getSystemResource (resource);
}
return UrlUtils.getResourceRoot (url, resource);
}
return null;
}
/**
* Sets the qualified name of the class on which to invoke the
* main() method. The source of the specified class will
* automatically be added to the class path of the forked JVM.
*
* @param name
* The qualified name of the class on which to invoke the
* main() method.
*/
public void setMainClass (final String name)
{
this.mainClass = name;
addClassPathEntry (_getClassSource (name));
}
/**
* Sets the class on which to invoke the main() method. The
* source of the specified class will automatically be added to the class path
* of the forked JVM.
*
* @param type
* The class on which to invoke the main() method, may be
* null.
*/
public void setMainClass (final Class type)
{
this.mainClass = (type != null) ? type.getName () : null;
addClassPathEntry (type);
}
/**
* Gets the command line arguments for the main() method.
*
* @return The command line arguments for the main() method.
*/
private String [] _getArguments ()
{
return this.cmdLineArgs.toArray (new String [this.cmdLineArgs.size ()]);
}
/**
* Adds the specified argument to the command line for the main()
* method.
*
* @param argument
* The argument to add, may be null.
*/
public void addArgument (final String argument)
{
if (argument != null)
{
this.cmdLineArgs.add (argument);
}
}
/**
* Adds the specified file path to the command line for the
* main() method.
*
* @param argument
* The argument to add, may be null.
*/
public void addArgument (final File argument)
{
if (argument != null)
{
this.cmdLineArgs.add (argument.getAbsolutePath ());
}
}
/**
* Adds the specified arguments to the command line for the
* main() method.
*
* @param arguments
* The arguments to add, may be null.
*/
public void addArguments (final String [] arguments)
{
if (arguments != null)
{
for (final String argument : arguments)
{
addArgument (argument);
}
}
}
/**
* Creates the command line for the new JVM based on the current
* configuration.
*
* @return The command line used to fork the JVM, never null.
*/
private Commandline _createCommandLine ()
{
/*
* NOTE: This method is designed to work with plexus-utils:1.1 which is used
* by all Maven versions before 2.0.6 regardless of our plugin dependency.
* Therefore, we use setWorkingDirectory(String) rather than
* setWorkingDirectory(File) and addArguments() rather than createArg().
*/
final Commandline cli = new Commandline ();
cli.setExecutable (this.executable);
if (this.workingDirectory != null)
{
cli.setWorkingDirectory (this.workingDirectory.getAbsolutePath ());
}
final String classPath = _getClassPath ();
if (classPath != null && classPath.length () > 0)
{
cli.addArguments (new String [] { "-cp", classPath });
}
if (this.mainClass != null && this.mainClass.length () > 0)
{
cli.addArguments (new String [] { this.mainClass });
}
cli.addArguments (_getArguments ());
return cli;
}
/**
* Forks a JVM using the previously set parameters.
*
* @return The exit code of the forked JVM.
* @throws Exception
* If the JVM could not be forked.
*/
public int run () throws Exception
{
return CommandLineUtils.executeCommandLine (_createCommandLine (), this.systemOut, this.systemErr);
}
/**
* Gets a string representation of the command line arguments.
*
* @return A string representation of the command line arguments.
*/
@Override
public String toString ()
{
return String.valueOf (_createCommandLine ());
}
}