org.apache.myfaces.custom.updateactionlistener.UpdateActionListenerTag Maven / Gradle / Ivy

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JSF components and utilities that can be used with any JSF implementation. This library is based on the JSF1.1 version of Tomahawk, but with minor source code and build changes to take advantage of JSF2.1 features. A JSF2.1 implementation is required to use this version of the Tomahawk library.
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.myfaces.custom.updateactionlistener;

import javax.el.ValueExpression;
import javax.faces.application.Application;
import javax.faces.component.ActionSource;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.webapp.UIComponentClassicTagBase;
import javax.faces.webapp.UIComponentTag;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;

/**
 * Registers an org.apache.myfaces.custom.updateactionlistener.UpdateActionListener 
 * at the parent component (which must be an ActionSource). 
 * 
 * When the parent's action fires the specified value is evaluated, 
 * then written into the specified property. 
 * 
 * Unless otherwise specified, all attributes accept static values or EL expressions. 
 * 
 * JSF 1.2 introduces a "setPropertyActionListener" with the same functionality like this. 
 *
 * @JSFJspTag
 *   name="t:updateActionListener"
 *   bodyContent="JSP"
 *   tagHandler="org.apache.myfaces.custom.updateactionlistener.UpdateActionListenerTagHandler"
 *   
 * @author Manfred Geiler (latest modification by $Author: lu4242 $)
 * @version $Revision: 692184 $ $Date: 2008-09-04 13:21:52 -0500 (Thu, 04 Sep 2008) $
 */
public class UpdateActionListenerTag
        extends TagSupport
{
    private static final long serialVersionUID = -6916153064327074092L;
    //private static final Log log = LogFactory.getLog(UpdateActionListenerTag.class);
    private ValueExpression _property;
    private ValueExpression _value;
    private String _converter;

    public UpdateActionListenerTag()
    {
    }

    /**
     * A value-binding that specifies a property to be updated when 
     * the parent's action occurs.
     * 
     * @JSFJspAttribute
     *   required="true"
     */
    public void setProperty(ValueExpression property)
    {
        _property = property;
    }

    /**
     *  A literal value or value-binding that specifies what 
     *  will be assigned to the destination specified by the 
     *  property attribute.
     * 
     * @JSFJspAttribute
     *   required="true"
     */
    public void setValue(ValueExpression value)
    {
        _value = value;
    }

    /**
     * The name of a registered Converter object which will be 
     * invoked to convert the value into an appropriate datatype 
     * for assigning to the specified property. If not specified 
     * then an appropriate converter will be selected automatically.
     * 
     * @JSFJspAttribute
     */
    public void setConverter(String converter)
    {
        _converter = converter;
    }

    public int doStartTag() throws JspException
    {
        if (_property == null) throw new JspException("property attribute not set");
        if (_value == null) throw new JspException("value attribute not set");
        if (_property.isLiteralText()) throw new JspException("property attribute is no valid value reference: " + _property);

        //Find parent UIComponentTag
        UIComponentClassicTagBase componentELTag = UIComponentClassicTagBase.getParentUIComponentClassicTagBase(pageContext);
        if (componentELTag == null){        
            UIComponentTag componentTag = UIComponentTag.getParentUIComponentTag(pageContext);
            if (componentTag == null)
            {
                throw new JspException("UpdateActionListenerTag has no UIComponentTag ancestor");
            }
        }

        if (componentELTag.getCreated())
        {
            //Component was just created, so we add the Listener
            UIComponent component = componentELTag.getComponentInstance();
            if (component instanceof ActionSource)
            {
                FacesContext facesContext = FacesContext.getCurrentInstance();
                Application application = facesContext.getApplication();
                UpdateActionListener al = new UpdateActionListener();
                al.setPropertyBinding(application.createValueBinding(_property.getExpressionString()));
                if (!_value.isLiteralText())
                {
                    al.setValueBinding(application.createValueBinding(_value.getExpressionString()));
                }
                else
                {
                    al.setValue(_value);
                }
                if (_converter != null)
                {
                    Converter converter = application.createConverter(_converter);
                    al.setConverter(converter);
                }
                ((ActionSource)component).addActionListener(al);
            }
            else
            {
                throw new JspException("Component " + component.getId() + " is no ActionSource");
            }
        }

        return Tag.SKIP_BODY;
    }

    public void release()
    {
        _property = null;
        _converter = null;
        _value = null;
    }

}