/*
* 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 java.lang.reflect.InvocationTargetException;
import java.util.Map;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.jelly.JellyTagException;
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;
/** A tag which sets a variable from the result of an expression
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @version $Revision: 1.18 $
*/
public class SetTag extends TagSupport {
/** The Log to which logging calls will be made. */
private static final Log log = LogFactory.getLog(SetTag.class);
/** The variable name to export. */
private String var;
/** The variable scope to export */
private String scope;
/** The expression to evaluate. */
private Expression value;
/** The default value */
private Expression defaultValue;
/** The target object on which to set a property. */
private Object target;
/** The name of the property to set on the target object. */
private String property;
/** Should we XML encode the body of this tag as text? */
private boolean encode = true;
public SetTag() {
}
// Tag interface
//-------------------------------------------------------------------------
public void doTag(XMLOutput output) throws JellyTagException {
// perform validation up front to fail fast
if ( var != null ) {
if ( target != null || property != null ) {
throw new JellyTagException( "The 'target' and 'property' attributes cannot be used in combination with the 'var' attribute" );
}
}
else {
if ( target == null ) {
throw new JellyTagException( "Either a 'var' or a 'target' attribute must be defined for this tag" );
}
if ( property == null ) {
throw new JellyTagException( "The 'target' attribute requires the 'property' attribute" );
}
}
Object answer = null;
if ( value != null ) {
answer = value.evaluate(context);
if (defaultValue != null && isEmpty(answer)) {
answer = defaultValue.evaluate(context);
}
}
else {
answer = getBodyText(isEncode());
}
if ( var != null ) {
if ( scope != null ) {
context.setVariable(var, scope, answer);
}
else {
context.setVariable(var, answer);
}
}
else {
setPropertyValue( target, property, answer );
}
}
// Properties
//-------------------------------------------------------------------------
/** Sets the variable name to define for this expression
*/
public void setVar(String var) {
this.var = var;
}
/**
* Sets the variable scope for this variable. For example setting this value to 'parent' will
* set this value in the parent scope. When Jelly is run from inside a Servlet environment
* then other scopes will be available such as 'request', 'session' or 'application'.
*
* Other applications may implement their own custom scopes.
*/
public void setScope(String scope) {
this.scope = scope;
}
/** Sets the expression to evaluate. */
public void setValue(Expression value) {
this.value = value;
}
/**
* Sets the default value to be used if the value exprsesion results
* in a null value or blank String
*/
public void setDefaultValue(Expression defaultValue) {
this.defaultValue = defaultValue;
}
/** Sets the target object on which to set a property. */
public void setTarget(Object target) {
this.target = target;
}
/** Sets the name of the property to set on the target object. */
public void setProperty(String property) {
this.property = property;
}
/**
* Returns whether the body of this tag will be XML encoded or not.
*/
public boolean isEncode() {
return encode;
}
/**
* Sets whether the body of the tag should be XML encoded as text (so that < and > are
* encoded as &lt; and &gt;) or leave the text as XML which is the default.
* This is only used if this tag is specified with no value so that the text body of this
* tag is used as the body.
*/
public void setEncode(boolean encode) {
this.encode = encode;
}
// Implementation methods
//-------------------------------------------------------------------------
protected void setPropertyValue( Object target, String property, Object value ) {
try {
if ( target instanceof Map ) {
Map map = (Map) target;
map.put( property, value );
}
else {
BeanUtils.setProperty( target, property, value );
}
} catch (InvocationTargetException e) {
log.error( "Failed to set the property: " + property + " on bean: " + target + " to value: " + value + " due to exception: " + e, e );
} catch (IllegalAccessException e) {
log.error( "Failed to set the property: " + property + " on bean: " + target + " to value: " + value + " due to exception: " + e, e );
}
}
/**
* @param value
* @return true if the given value is null or an empty String
*/
protected boolean isEmpty(Object value) {
if (value == null) {
return true;
}
if (value instanceof String) {
String s = (String) value;
return s.length() == 0;
}
return false;
}
}