/*
* $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/taglibs/beanshell/src/java/org/apache/commons/jelly/tags/beanshell/BeanShellExpressionFactory.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $
* $Revision: 1.1 $
* $Date: 2002/05/21 07:58:55 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2002 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* $Id: BeanShellExpressionFactory.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $
*/
package org.apache.commons.jelly.tags.define;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.jelly.JellyException;
import org.apache.commons.jelly.MissingAttributeException;
import org.apache.commons.jelly.Tag;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jelly.impl.Attribute;
import org.apache.commons.jelly.impl.DynamicBeanTag;
import org.apache.commons.jelly.impl.TagFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Binds a Java bean to the given named Jelly tag so that the attributes of
* the tag set the bean properties..
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @version $Revision: 1.1 $
*/
public class BeanTag extends DefineTagSupport {
/** The Log to which logging calls will be made. */
private static final Log log = LogFactory.getLog(BeanTag.class);
/** An empty Map as I think Collections.EMPTY_MAP is only JDK 1.3 onwards */
private static final Map EMPTY_MAP = new HashMap();
/** the name of the tag to create */
private String name;
/** the Java class name to use for the tag */
private String className;
/** the ClassLoader used to load beans */
private ClassLoader classLoader;
/** the name of the attribute used for the variable name */
private String varAttribute = "var";
/** the attribute definitions for this dynamic tag */
private Map attributes;
/**
* Adds a new attribute definition to this dynamic tag
*/
public void addAttribute(Attribute attribute) {
if ( attributes == null ) {
attributes = new HashMap();
}
attributes.put( attribute.getName(), attribute );
}
// Tag interface
//-------------------------------------------------------------------------
public void doTag(XMLOutput output) throws Exception {
invokeBody(output);
if (name == null) {
throw new MissingAttributeException("name");
}
if (className == null) {
throw new MissingAttributeException("className");
}
Class theClass = null;
try {
ClassLoader classLoader = getClassLoader();
theClass = classLoader.loadClass(className);
}
catch (ClassNotFoundException e) {
try {
theClass = getClass().getClassLoader().loadClass(className);
}
catch (ClassNotFoundException e2) {
try {
theClass = Class.forName(className);
}
catch (ClassNotFoundException e3) {
log.error( "Could not load class: " + className + " exception: " + e, e );
throw new JellyException(
"Could not find class: "
+ className
+ " using ClassLoader: "
+ classLoader);
}
}
}
final Class beanClass = theClass;
final Method invokeMethod = getInvokeMethod( theClass );
final Map beanAttributes = (attributes != null) ? attributes : EMPTY_MAP;
TagFactory factory = new TagFactory() {
public Tag createTag() {
return new DynamicBeanTag(beanClass, beanAttributes, varAttribute, invokeMethod);
}
};
getTagLibrary().registerBeanTag(name, factory);
// now lets clear the attributes for next invocation and help the GC
attributes = null;
}
// Properties
//-------------------------------------------------------------------------
/**
* Sets the name of the tag to create
*/
public void setName(String name) {
this.name = name;
}
/**
* Sets the Java class name to use for the tag
*/
public void setClassName(String className) {
this.className = className;
}
/**
* Sets the ClassLoader to use to load the class.
* If no value is set then the current threads context class
* loader is used.
*/
public void setClassLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
/**
* @return the ClassLoader to use to load classes
* or will use the thread context loader if none is specified.
*/
public ClassLoader getClassLoader() {
if ( classLoader == null ) {
ClassLoader answer = Thread.currentThread().getContextClassLoader();
if ( answer == null ) {
answer = getClass().getClassLoader();
}
return answer;
}
return classLoader;
}
/**
* Sets the name of the attribute used to define the bean variable that this dynamic
* tag will output its results as. This defaults to 'var' though this property
* can be used to change this if it conflicts with a bean property called 'var'.
*/
public void setVarAttribute(String varAttribute) {
this.varAttribute = varAttribute;
}
// Implementation methods
//-------------------------------------------------------------------------
/**
* Extracts the invoke method for the class if one is used.
*/
protected Method getInvokeMethod( Class theClass ) throws Exception {
return null;
}
}