convertertag.java

一个使用struts+hibernate+spring开发的完的网站源代码。

/*
 * Copyright 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 javax.faces.webapp;

import javax.faces.application.Application;
import javax.faces.component.UIComponent;
import javax.faces.component.ValueHolder;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.el.ValueBinding;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;

/**
 * @author Manfred Geiler (latest modification by $Author: mwessendorf $)
 * @version $Revision: 1.4 $ $Date: 2004/07/01 22:00:53 $
 */
public class ConverterTag
        extends TagSupport
{
    private String _converterId;

    public ConverterTag()
    {
        super();
    }

    public void setConverterId(String converterId)
    {
        _converterId = converterId;
    }

    public int doStartTag()
            throws JspException
    {
        UIComponentTag componentTag = UIComponentTag.getParentUIComponentTag(pageContext);
        if (componentTag == null)
        {
            throw new JspException("no parent UIComponentTag found");
        }
        if (!componentTag.getCreated())
        {
            return Tag.SKIP_BODY;
        }

        Converter converter = createConverter();

        UIComponent component = componentTag.getComponentInstance();
        if (component == null)
        {
            throw new JspException("parent UIComponentTag has no UIComponent");
        }
        if (!(component instanceof ValueHolder))
        {
            throw new JspException("UIComponent is no ValueHolder");
        }
        ((ValueHolder)component).setConverter(converter);

        return Tag.SKIP_BODY;
    }

    public void release()
    {
        super.release();
        _converterId = null;
    }

    protected Converter createConverter()
            throws JspException
    {
        FacesContext facesContext = FacesContext.getCurrentInstance();
        Application application = facesContext.getApplication();
        if (UIComponentTag.isValueReference(_converterId))
        {
            ValueBinding vb = facesContext.getApplication().createValueBinding(_converterId);
            return application.createConverter((String)vb.getValue(facesContext));
        }
        else
        {
            return application.createConverter(_converterId);
        }
    }
}