| /* |
| * 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.util; |
| |
| import groovy.lang.Binding; |
| import groovy.lang.GroovyObject; |
| import groovy.lang.MetaClass; |
| import groovy.lang.MissingMethodException; |
| import groovy.lang.MissingPropertyException; |
| import groovy.lang.Script; |
| import org.codehaus.groovy.runtime.InvokerHelper; |
| |
| /** |
| * {@link Script} that performs method invocations and property access like {@link groovy.lang.Closure} does. |
| * |
| * <p> |
| * {@link DelegatingScript} is a convenient basis for loading a custom-defined DSL as a {@link Script}, then execute it. |
| * The following sample code illustrates how to do it: |
| * |
| * <pre> |
| * class MyDSL { |
| * public void foo(int x, int y, Closure z) { ... } |
| * public void setBar(String a) { ... } |
| * } |
| * |
| * CompilerConfiguration cc = new CompilerConfiguration(); |
| * cc.setScriptBaseClass(DelegatingScript.class.getName()); |
| * GroovyShell sh = new GroovyShell(cl,new Binding(),cc); |
| * DelegatingScript script = (DelegatingScript)sh.parse(new File("my.dsl")) |
| * script.setDelegate(new MyDSL()); |
| * script.run(); |
| * </pre> |
| * |
| * <p> |
| * <tt>my.dsl</tt> can look like this: |
| * |
| * <pre> |
| * foo(1,2) { |
| * .... |
| * } |
| * bar = ...; |
| * </pre> |
| * |
| * <p> |
| * {@link DelegatingScript} does this by delegating property access and method invocation to the <tt>delegate</tt> object. |
| * |
| * <p> |
| * More formally speaking, given the following script: |
| * |
| * <pre> |
| * a = 1; |
| * b(2); |
| * </pre> |
| * |
| * <p> |
| * Using {@link DelegatingScript} as the base class, the code will run as: |
| * |
| * <pre> |
| * delegate.a = 1; |
| * delegate.b(2); |
| * </pre> |
| * |
| * ... whereas in plain {@link Script}, this will be run as: |
| * |
| * <pre> |
| * binding.setProperty("a",1); |
| * ((Closure)binding.getProperty("b")).call(2); |
| * </pre> |
| */ |
| public abstract class DelegatingScript extends Script { |
| private Object delegate; |
| private MetaClass metaClass; |
| |
| protected DelegatingScript() { |
| super(); |
| } |
| |
| protected DelegatingScript(Binding binding) { |
| super(binding); |
| } |
| |
| /** |
| * Sets the delegation target. |
| */ |
| public void setDelegate(Object delegate) { |
| this.delegate = delegate; |
| this.metaClass = InvokerHelper.getMetaClass(delegate.getClass()); |
| } |
| |
| @Override |
| public Object invokeMethod(String name, Object args) { |
| try { |
| if (delegate instanceof GroovyObject) { |
| return ((GroovyObject) delegate).invokeMethod(name, args); |
| } |
| return metaClass.invokeMethod(delegate, name, args); |
| } catch (MissingMethodException mme) { |
| return super.invokeMethod(name, args); |
| } |
| } |
| |
| @Override |
| public Object getProperty(String property) { |
| try { |
| return metaClass.getProperty(delegate,property); |
| } catch (MissingPropertyException e) { |
| return super.getProperty(property); |
| } |
| } |
| |
| @Override |
| public void setProperty(String property, Object newValue) { |
| try { |
| metaClass.setProperty(delegate,property,newValue); |
| } catch (MissingPropertyException e) { |
| super.setProperty(property,newValue); |
| } |
| } |
| |
| public Object getDelegate() { |
| return delegate; |
| } |
| } |