struts-sandbox/tiles-original/core-library/src/java/org/apache/taglib/tiles/PutListTag.java

/*
 * Copyright 2004-2005 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.taglib.tiles;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.tiles.AttributeDefinition;
import org.apache.tiles.UntypedAttribute;

/**
 * PutList tag implementation.
 */
public class PutListTag
    extends TagSupport
    implements ComponentConstants, AddTagParent, PutListTagParent {

    /** 
     * Name of this attribute. 
     */
    private String attributeName = null;
    
    /** 
     * The list itself. 
     */
    private List list = null;
    
    /** 
     * Role attribute. 
     */
    private String role = null;

    /**
     * Default constructor.
     */
    public PutListTag() {
        super();
    }

    /**
     * Release all allocated resources.
     */
    public void release() {
        super.release();
        attributeName = null;
        role = null;
    }

    /**
     * Release all internal resources.
     */
    protected void releaseInternal() {
        list = null;
    }

    /**
     * Set property.
     */
    public void setName(String name) {
        this.attributeName = name;
    }

    /**
     * Get property.
     */
    public String getName() {
        return attributeName;
    }

    /**
     * Set role attribute.
     * @param role The role the user must be in to store content.
     */
    public void setRole(String role) {
        this.role = role;
    }

    /**
     * Get role attribute.
     */
    public String getRole() {
        return role;
    }

    /**
     * Get list defined in tag.
     */
    public List getList() {
        return list;
    }

    /**
     * Set property.
     */
    public void addElement(Object value) {
        if (list == null) {
            list = new ArrayList();
        }
        
        list.add(value);
    }

    /**
     * Process nested ≶putList> tag.
     * Method calls by nested ≶putList> tags.
     * Nested list is added to current list.
     * If role is defined, nested attribute is wrapped into an untypped definition
     * containing attribute value and role.
     */
    public void processNestedTag(PutListTag nestedTag) throws JspException {
        // Get real value and check role
        // If role is set, add it in attribute definition if any.
        // If no attribute definition, create untyped one, and set role.
        Object attributeValue = nestedTag.getList();

        if (nestedTag.getRole() != null) {
            AttributeDefinition def = new UntypedAttribute(attributeValue);
            def.setRole(nestedTag.getRole());
            attributeValue = def;
        }
        
        // now add attribute to enclosing parent (i.e. : this object)
        addElement(attributeValue);
    }

    /**
     * Process nested ≶add> tag.
     * Method calls by nested ≶add> tags.
     * Nested attribute is added to current list.
     * If role is defined, nested attribute is wrapped into an untypped definition
     * containing attribute value and role.
     */
    public void processNestedTag(AddTag nestedTag) throws JspException {
        // Get real value and check role
        // If role is set, add it in attribute definition if any.
        // If no attribute definition, create untyped one, and set role.
        Object attributeValue = nestedTag.getRealValue();
        AttributeDefinition def;

        if (nestedTag.getRole() != null) {
            try {
                def = ((AttributeDefinition) attributeValue);
            } catch (ClassCastException ex) {
                def = new UntypedAttribute(attributeValue);
            }
            def.setRole(nestedTag.getRole());
            attributeValue = def;
        }
        
        // now add attribute to enclosing parent (i.e. : this object)
        addElement(attributeValue);
    }

    /**
     * Do start tag.
     */
    public int doStartTag() throws JspException {
        return EVAL_BODY_INCLUDE;
    }

    /**
     * Do end tag.
     */
    public int doEndTag() throws JspException {
        PutListTagParent enclosingParent = findEnclosingParent();
        enclosingParent.processNestedTag(this);
        // Clear list to avoid reuse
        releaseInternal();
        return EVAL_PAGE;
    }

    /**
     * Find enclosing parent tag accepting this tag.
     * @throws JspException If we can't find an appropriate enclosing tag.
     */
    protected PutListTagParent findEnclosingParent() throws JspException {
        try {
            PutListTagParent parent =
                (PutListTagParent) findAncestorWithClass(this,
                    PutListTagParent.class);
                    
            if (parent == null) {
                throw new JspException("Error - tag putList : enclosing tag doesn't accept 'putList' tag.");
            }
            
            return parent;
            
        } catch (ClassCastException ex) {
            throw new JspException("Error - tag putList : enclosing tag doesn't accept 'putList' tag.");
        }
    }

}