001 /***************************************************************************** 002 * Copyright (C) PicoContainer Organization. All rights reserved. * 003 * ------------------------------------------------------------------------- * 004 * The software in this package is published under the terms of the BSD * 005 * style license a copy of which has been included with this distribution in * 006 * the LICENSE.txt file. * 007 * * 008 * Original code by Leo Simons * 009 *****************************************************************************/ 010 package org.picocontainer.script.bsh; 011 012 import bsh.EvalError; 013 import bsh.Interpreter; 014 import org.picocontainer.Parameter; 015 import org.picocontainer.PicoContainer; 016 import org.picocontainer.PicoCompositionException; 017 import org.picocontainer.adapters.AbstractAdapter; 018 019 import java.io.IOException; 020 import java.io.InputStreamReader; 021 import java.io.Reader; 022 import java.net.URL; 023 import java.util.Arrays; 024 import java.util.Collections; 025 import java.lang.reflect.Type; 026 027 /** 028 * This adapter relies on <a href="http://beanshell.org/">Bsh</a> for instantiation 029 * (and possibly also initialisation) of component instances. 030 * <p/> 031 * When {@link org.picocontainer.ComponentAdapter#getComponentInstance} is called (by PicoContainer), 032 * the adapter instance will look for a script with the same name as the component implementation 033 * class (but with the .bsh extension). This script must reside in the same folder as the class. 034 * (It's ok to have them both in a jar). 035 * <p/> 036 * The bsh script's only contract is that it will have to instantiate a bsh variable called 037 * "instance". 038 * <p/> 039 * The script will have access to the following variables: 040 * <ul> 041 * <li>addAdapter - the adapter calling the script</li> 042 * <li>picoContainer - the MutablePicoContainer calling the addAdapter</li> 043 * <li>componentKey - the component key</li> 044 * <li>componentImplementation - the component implementation</li> 045 * <li>parameters - the ComponentParameters (as a List)</li> 046 * </ul> 047 * @author <a href="mail at leosimons dot com">Leo Simons</a> 048 * @author Aslak Hellesoy 049 */ 050 @SuppressWarnings({ "unchecked", "serial" }) 051 public class BeanShellAdapter extends AbstractAdapter { 052 private final Parameter[] parameters; 053 054 private Object instance = null; 055 056 /** 057 * Classloader to set for the BeanShell interpreter. 058 */ 059 private final ClassLoader classLoader; 060 061 public BeanShellAdapter(final Object componentKey, final Class<?> componentImplementation, final Parameter[] parameters, final ClassLoader classLoader) { 062 super(componentKey, componentImplementation); 063 this.parameters = parameters; 064 this.classLoader = classLoader; 065 } 066 067 public BeanShellAdapter(final Object componentKey, final Class<?> componentImplementation, final Parameter... parameters) { 068 this(componentKey, componentImplementation, parameters, BeanShellAdapter.class.getClassLoader()); 069 } 070 071 public Object getComponentInstance(PicoContainer pico, Type into) 072 throws PicoCompositionException 073 { 074 075 if (instance == null) { 076 try { 077 Interpreter i = new Interpreter(); 078 i.setClassLoader(classLoader); 079 i.set("addAdapter", this); 080 i.set("picoContainer", pico); 081 i.set("componentKey", getComponentKey()); 082 i.set("componentImplementation", getComponentImplementation()); 083 i.set("parameters", parameters != null ? Arrays.asList(parameters) : Collections.EMPTY_LIST); 084 i.eval("import " + getComponentImplementation().getName() + ";"); 085 086 String scriptPath = "/" + getComponentImplementation().getName().replace('.', '/') + ".bsh"; 087 088 // Inside IDEA, this relies on the compilation output path being the same directory as the source path. 089 // kludge - copy ScriptableDemoBean.bsh to the same location in the test output compile class path. 090 // the same problem exists for maven, but some custom jelly script will be able to fix that. 091 URL scriptURL = getComponentImplementation().getResource(scriptPath); 092 if (scriptURL == null) { 093 throw new BeanShellScriptCompositionException("Couldn't load script at path " + scriptPath); 094 } 095 Reader sourceReader = new InputStreamReader(scriptURL.openStream()); 096 i.eval(sourceReader, i.getNameSpace(), scriptURL.toExternalForm()); 097 098 instance = i.get("instance"); 099 if (instance == null) { 100 throw new BeanShellScriptCompositionException("The 'instance' variable was not instantiated"); 101 } 102 } catch (EvalError e) { 103 throw new BeanShellScriptCompositionException(e); 104 } catch (IOException e) { 105 throw new BeanShellScriptCompositionException(e); 106 } 107 } 108 return instance; 109 } 110 111 public void verify(PicoContainer pico) { 112 } 113 114 public String getDescriptor() { 115 return "BeanShellConsole"; 116 } 117 }