/*
* $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/define/DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $
* $Revision: 1.7 $
* $Date: 2002/05/17 15:18:12 $
*
* ====================================================================
*
* 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: DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $
*/
package org.apache.commons.jelly.tags.define;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.util.Iterator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.beanutils.ConvertingWrapDynaBean;
import org.apache.commons.collections.BeanMap;
import org.apache.commons.jelly.DynaBeanTagSupport;
import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.JellyException;
import org.apache.commons.jelly.MissingAttributeException;
import org.apache.commons.jelly.Script;
import org.apache.commons.jelly.TagSupport;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jelly.expression.Expression;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* This tag is bound onto a Java Bean class. When the tag is invoked a bean will be created
* using the tags attributes.
* The bean may also have an invoke method called invoke(), run(), execute() or some such method
* which will be invoked after the bean has been configured.</p>
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @author <a href="mailto:jason@zenplex.com">Jason van Zyl</a>
* @version $Revision: 1.7 $
*/
public class BeanTag extends DynaBeanTagSupport {
/** The Log to which logging calls will be made. */
private static final Log log = LogFactory.getLog(BeanTag.class);
/** Empty arguments for Method.invoke() */
private static final Object[] emptyArgs = {};
/** the bean class */
private Class beanClass;
/** the current bean instance */
private Object bean;
/** the method to invoke on the bean */
private Method method;
/**
* the tag attribute name that is used to declare the name
* of the variable to export after running this tag
*/
private String variableNameAttribute;
/** the current variable name that the bean should be exported as */
private String var;
/** the set of attribute names we've already set */
private Set setAttributesSet = new HashSet();
/** the attribute definitions */
private Map attributes;
public BeanTag(Class beanClass, Map attributes, String variableNameAttribute, Method method) {
this.beanClass = beanClass;
this.method = method;
this.attributes = attributes;
this.variableNameAttribute = variableNameAttribute;
}
public void beforeSetAttributes() throws Exception {
// create a new dynabean before the attributes are set
bean = beanClass.newInstance();
setDynaBean( new ConvertingWrapDynaBean( bean ) );
setAttributesSet.clear();
}
public void setAttribute(String name, Object value) throws Exception {
boolean isVariableName = false;
if (variableNameAttribute != null ) {
if ( variableNameAttribute.equals( name ) ) {
if (value == null) {
var = null;
}
else {
var = value.toString();
}
isVariableName = true;
}
}
if (! isVariableName) {
// #### strictly speaking we could
// know what attributes are specified at compile time
// so this dynamic set is unnecessary
setAttributesSet.add(name);
// we could maybe implement attribute specific validation here
super.setAttribute(name, value);
}
}
// Tag interface
//-------------------------------------------------------------------------
public void doTag(XMLOutput output) throws Exception {
// lets find any attributes that are not set and
for ( Iterator iter = attributes.values().iterator(); iter.hasNext(); ) {
Attribute attribute = (Attribute) iter.next();
String name = attribute.getName();
if ( ! setAttributesSet.contains( name ) ) {
if ( attribute.isRequired() ) {
throw new MissingAttributeException(name);
}
// lets get the default value
Object value = null;
Expression expression = attribute.getDefaultValue();
if ( expression != null ) {
value = expression.evaluate(context);
}
// only set non-null values?
if ( value != null ) {
super.setAttribute(name, value);
}
}
}
invokeBody(output);
// export the bean if required
if ( var != null ) {
context.setVariable(var, bean);
}
// now, I may invoke the 'execute' method if I have one
if ( method != null ) {
try {
method.invoke( bean, emptyArgs );
}
catch (IllegalAccessException e) {
methodInvocationError(bean, method, e);
}
catch (IllegalArgumentException e) {
methodInvocationError(bean, method, e);
}
catch (InvocationTargetException e) {
// methodInvocationError(bean, method, e);
Throwable inner = e.getTargetException();
if ( inner instanceof Exception )
{
throw (Exception) inner;
}
else
{
throw new JellyException( inner );
}
}
}
}
/**
* Report the state of the bean when method invocation fails
* so that the user can determine any problems that might
* be occuring while using dynamic jelly beans.
*
* @param bean Bean on which <code>method</code was invoked
* @param method Method that was invoked
* @param e Exception throw when <code>method</code> was invoked
*/
private void methodInvocationError(Object bean, Method method, Exception e) throws Exception {
log.error("Could not invoke " + method, e);
BeanMap beanMap = new BeanMap(bean);
log.error("Bean properties:");
for (Iterator i = beanMap.keySet().iterator(); i.hasNext();) {
String property = (String) i.next();
Object value = beanMap.get(property);
log.error(property + " -> " + value);
}
log.error(beanMap);
throw e;
}
// Properties
//-------------------------------------------------------------------------
/**
* @return the bean that has just been created
*/
public Object getBean() {
return bean;
}
}