/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Groovy.java
* Copyright (C) 2009-2012 University of Waikato, Hamilton, New Zealand
*/
package weka.core.scripting;
import java.io.File;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import weka.core.RevisionHandler;
import weka.core.RevisionUtils;
/**
* A helper class for <a href="http://groovy.codehaus.org/" target="_blank">Groovy</a>.
* <p/>
* In order to use Groovy, the jar containing all the classes must be present
* in the CLASSPATH. This jar is normally found in the <i>embeddable</i>
* sub-directory of the Groovy installation.
* <p/>
* Tested with Groovy 1.5.7.
*
* @author fracpete (fracpete at waikato dot ac dot nz)
* @version $Revision: 8034 $
*/
public class Groovy
implements Serializable, RevisionHandler {
/** for serialization. */
private static final long serialVersionUID = -2628766602043134673L;
/** the classname of the Groovy classloader. */
public final static String CLASS_GROOVYCLASSLOADER = "groovy.lang.GroovyClassLoader";
/** whether the Groovy classes are in the Classpath. */
protected static boolean m_Present = false;
static {
try {
Class.forName(CLASS_GROOVYCLASSLOADER);
m_Present = true;
}
catch (Exception e) {
m_Present = false;
}
}
/** the classloader. */
protected Object m_ClassLoader;
/**
* default constructor, tries to instantiate a Groovy classloader.
*/
public Groovy() {
m_ClassLoader = newClassLoader();
}
/**
* returns the currently used Groovy classloader.
*
* @return the classloader, can be null
*/
public Object getClassLoader() {
return m_ClassLoader;
}
/**
* executes the specified method on the current interpreter and returns the
* result, if any.
*
* @param methodName the name of the method
* @param paramClasses the classes of the parameters
* @param paramValues the values of the parameters
* @return the return value of the method, if any (in that case null)
*/
public Object invoke(String methodName, Class[] paramClasses, Object[] paramValues) {
Object result;
result = null;
if (getClassLoader() != null)
result = invoke(getClassLoader(), methodName, paramClasses, paramValues);
return result;
}
/**
* returns whether the Groovy classes are present or not, i.e. whether the
* classes are in the classpath or not
*
* @return whether the Groovy classes are available
*/
public static boolean isPresent() {
return m_Present;
}
/**
* initializes and returns a Groovy Interpreter.
*
* @return the interpreter or null if Groovy classes not present
*/
public static Object newClassLoader() {
Object result;
Class<?> cls;
Constructor constr;
result = null;
if (isPresent()) {
try {
cls = Class.forName(CLASS_GROOVYCLASSLOADER);
constr = cls.getConstructor(new Class[]{ClassLoader.class});
result = constr.newInstance(Groovy.class.getClassLoader());
}
catch (Exception e) {
e.printStackTrace();
result = null;
}
}
return result;
}
/**
* loads the module and returns a new instance of it as instance of the
* provided Java class template.
*
* @param file the Groovy module file
* @param template the template for the returned Java object
* @return the Groovy object
*/
public static Object newInstance(File file, Class template) {
Object result;
Object interpreter;
Class cls;
result = null;
if (!isPresent())
return result;
interpreter = newClassLoader();
if (interpreter == null)
return result;
try {
cls = (Class) invoke(interpreter, "parseClass", new Class[]{File.class}, new Object[]{file});
result = cls.newInstance();
}
catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* executes the specified method and returns the result, if any.
*
* @param o the object the method should be called from,
* e.g., a Groovy Interpreter
* @param methodName the name of the method
* @param paramClasses the classes of the parameters
* @param paramValues the values of the parameters
* @return the return value of the method, if any (in that case null)
*/
public static Object invoke(Object o, String methodName, Class[] paramClasses, Object[] paramValues) {
Method m;
Object result;
result = null;
try {
m = o.getClass().getMethod(methodName, paramClasses);
result = m.invoke(o, paramValues);
}
catch (Exception e) {
e.printStackTrace();
result = null;
}
return result;
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 8034 $");
}
/**
* If no arguments are given, it just prints the presence of the Groovy
* classes, otherwise it expects a Groovy filename to execute.
*
* @param args commandline arguments
*/
public static void main(String[] args) {
if (args.length == 0) {
System.out.println("Groovy present: " + isPresent());
}
else {
Groovy groovy = new Groovy();
if (groovy.getClassLoader() == null) {
System.err.println("Cannot instantiate Groovy ClassLoader!");
}
else {
Object groovyObject = Groovy.newInstance(new File(args[0]), Object.class);
Groovy.invoke(groovyObject, "run", new Class[]{}, new Object[]{});
}
}
}
}