/*
* Copyright 2002,2004 The Apache Software Foundation.
*
* Licensed 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 org.apache.commons.jelly.tags.core;
import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.JellyTagException;
import org.apache.commons.jelly.MissingAttributeException;
import org.apache.commons.jelly.TagSupport;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jelly.util.ClassLoaderUtils;
/**
* A tag which can retrieve the value of a static field of a given class.
* The following attributes are required:<br />
* <ul>
* <li>var - The variable to which to assign the resulting value.</li>
* <li>field - The name of the static field to retrieve.</li>
* <li>className - The name of the class containing the static field.</li>
* </ul>
*
* Example usage:
* <pre>
* <j:getStatic var="closeOperation" className="javax.swing.JFrame"
* field="EXIT_ON_CLOSE"/>
* </pre>
*
* @version $Revision: 155420 $
*/
public class GetStaticTag extends TagSupport {
/** The variable to which to assign the resulting value. */
private String var;
/** The name of the static field to retrieve. */
private String field;
/** The name of the class containing the static field. */
private String className;
/**
* Sets the name of the variable exported by this tag.
*
* @param var The variable name.
*/
public void setVar(String var) {
this.var = var;
}
/**
* Sets the name of the field to retrieve.
*
* @param method The method name
*/
public void setField(String field) {
this.field = field;
}
/**
* Sets the fully qualified name of the class containing the static field.
*
* @param className The name of the class.
*/
public void setClassName(String className) {
this.className = className;
}
// Tag interface
//------------------------------------------------------------------------
public void doTag(XMLOutput output) throws JellyTagException {
String message = null;
if(var == null)
message = "var";
else if(field == null)
message = "field";
else if(className == null)
message = "className";
if(message != null)
throw new MissingAttributeException(message);
try {
Class type = ClassLoaderUtils.getClassLoader(getClass()).loadClass(className);
Object result = type.getField(field).get(null);
JellyContext context = getContext();
context.setVariable(var, result);
} catch(Throwable t) {
throw
new JellyTagException("Could not access " + className + "." +
var + ". Original exception message: " +
t.getMessage(), t);
}
}
}
/* Emacs configuration
* Local variables: **
* mode: java **
* c-basic-offset: 4 **
* indent-tabs-mode: nil **
* End: **
*/