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Groovy: A powerful, dynamic language for the JVM
/*
* 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.
*/
package groovy.lang;
import org.codehaus.groovy.ast.expr.ArgumentListExpression;
import org.codehaus.groovy.control.CompilationFailedException;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import org.codehaus.groovy.runtime.InvokerHelper;
import java.io.File;
import java.io.IOException;
/**
* This object represents a Groovy script
*
* @author James Strachan
* @author Guillaume Laforge
*/
public abstract class Script extends GroovyObjectSupport {
private Binding binding;
protected Script() {
this(new Binding());
}
protected Script(Binding binding) {
this.binding = binding;
}
public Binding getBinding() {
return binding;
}
public void setBinding(Binding binding) {
this.binding = binding;
}
public Object getProperty(String property) {
try {
return binding.getVariable(property);
} catch (MissingPropertyException e) {
return super.getProperty(property);
}
}
public void setProperty(String property, Object newValue) {
if ("binding".equals(property))
setBinding((Binding) newValue);
else if("metaClass".equals(property))
setMetaClass((MetaClass)newValue);
else
binding.setVariable(property, newValue);
}
/**
* Invoke a method (or closure in the binding) defined.
*
* @param name method to call
* @param args arguments to pass to the method
* @return value
*/
public Object invokeMethod(String name, Object args) {
try {
return super.invokeMethod(name, args);
}
// if the method was not found in the current scope (the script's methods)
// let's try to see if there's a method closure with the same name in the binding
catch (MissingMethodException mme) {
try {
if (name.equals(mme.getMethod())) {
Object boundClosure = getProperty(name);
if (boundClosure != null && boundClosure instanceof Closure) {
return ((Closure) boundClosure).call((Object[])args);
} else {
throw mme;
}
} else {
throw mme;
}
} catch (MissingPropertyException mpe) {
throw mme;
}
}
}
/**
* The main instance method of a script which has variables in scope
* as defined by the current {@link Binding} instance.
*/
public abstract Object run();
// println helper methods
/**
* Prints a newline to the current 'out' variable which should be a PrintWriter
* or at least have a println() method defined on it.
* If there is no 'out' property then print to standard out.
*/
public void println() {
Object object;
try {
object = getProperty("out");
} catch (MissingPropertyException e) {
System.out.println();
return;
}
InvokerHelper.invokeMethod(object, "println", ArgumentListExpression.EMPTY_ARRAY);
}
/**
* Prints the value to the current 'out' variable which should be a PrintWriter
* or at least have a print() method defined on it.
* If there is no 'out' property then print to standard out.
*/
public void print(Object value) {
Object object;
try {
object = getProperty("out");
} catch (MissingPropertyException e) {
DefaultGroovyMethods.print(System.out,value);
return;
}
InvokerHelper.invokeMethod(object, "print", new Object[]{value});
}
/**
* Prints the value and a newline to the current 'out' variable which should be a PrintWriter
* or at least have a println() method defined on it.
* If there is no 'out' property then print to standard out.
*/
public void println(Object value) {
Object object;
try {
object = getProperty("out");
} catch (MissingPropertyException e) {
DefaultGroovyMethods.println(System.out,value);
return;
}
InvokerHelper.invokeMethod(object, "println", new Object[]{value});
}
/**
* Prints a formatted string using the specified format string and argument.
*
* @param format the format to follow
* @param value the value to be formatted
*/
public void printf(String format, Object value) {
Object object;
try {
object = getProperty("out");
} catch (MissingPropertyException e) {
DefaultGroovyMethods.printf(System.out, format, value);
return;
}
InvokerHelper.invokeMethod(object, "printf", new Object[] { format, value });
}
/**
* Prints a formatted string using the specified format string and arguments.
*
* @param format the format to follow
* @param values an array of values to be formatted
*/
public void printf(String format, Object[] values) {
Object object;
try {
object = getProperty("out");
} catch (MissingPropertyException e) {
DefaultGroovyMethods.printf(System.out, format, values);
return;
}
InvokerHelper.invokeMethod(object, "printf", new Object[] { format, values });
}
/**
* A helper method to allow the dynamic evaluation of groovy expressions using this
* scripts binding as the variable scope
*
* @param expression is the Groovy script expression to evaluate
*/
public Object evaluate(String expression) throws CompilationFailedException {
GroovyShell shell = new GroovyShell(getClass().getClassLoader(), binding);
return shell.evaluate(expression);
}
/**
* A helper method to allow the dynamic evaluation of groovy expressions using this
* scripts binding as the variable scope
*
* @param file is the Groovy script to evaluate
*/
public Object evaluate(File file) throws CompilationFailedException, IOException {
GroovyShell shell = new GroovyShell(getClass().getClassLoader(), binding);
return shell.evaluate(file);
}
/**
* A helper method to allow scripts to be run taking command line arguments
*/
public void run(File file, String[] arguments) throws CompilationFailedException, IOException {
GroovyShell shell = new GroovyShell(getClass().getClassLoader(), binding);
shell.run(file, arguments);
}
}