gettag.java

来自「jakarta-taglibs」· Java 代码 · 共 91 行

/*
 * Copyright 1999,2004 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.taglibs.io;

import javax.servlet.ServletContext;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.Tag;

/** Allows a named bean, or a property of a named bean to be used as input 
  * to a pipe.
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.2 $
  */
public class GetTag extends AbstractTag {

    /** The name used  */
    private String name;

    /** The property to extract from the bean */
    private String property;
    
    
    public GetTag() {
    }

    // Tag interface
    //-------------------------------------------------------------------------                        
    public int doStartTag() throws JspException {
        Tag parent = getParent();
        if ( parent instanceof PipeConsumer ) {
            PipeConsumer consumer = (PipeConsumer) parent;
            consumer.setReader( PipeHelper.getReader( getValue() ) );
        }
        else if ( parent instanceof PipeProducer ) {
            PipeProducer producer = (PipeProducer) parent;
            producer.setWriter( PipeHelper.getWriter( getValue() ) );
        }
        else {
            throw new JspException( "<io:get> tag must be included inside either a PipeConsumer or PipeProducer tag" );
        }
        return SKIP_BODY;
    }
    
    public void release() {
        super.release();
        name = null;
        property = null;
    }
    
    
   
    // Properties
    //-------------------------------------------------------------------------                    
    public Object getValue() throws JspException {
        Object bean = pageContext.findAttribute( name );
        if ( bean != null ) {
            if ( property == null ) {
                return bean;
            }
            else {
                return BeanHelper.getProperty( bean, property );
            }
        }
        return null;
    }
    
    public void setName(String name) {
        this.name = name;
    }
    
    public void setProperty(String property) {
        this.property = property;
    }
}