nestedpropertytag.java

structs源码

/*
 * $Id: NestedPropertyTag.java 471754 2006-11-06 14:55:09Z husted $
 *
 * 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.struts.taglib.nested;

import org.apache.struts.taglib.TagUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;

/**
 * NestedPropertyTag.
 *
 * The one of only two additions in this nested suite of tags. This is so that
 * you can specify extra levels of nesting in one elegant tag rather than
 * having to propagate and manage an extra dot notated property in nested
 * child tags.
 *
 * It's simply recognised by the helper class and it's property is added to
 * the nesting list.
 *
 * @version $Rev: 471754 $ $Date: 2004-10-16 12:38:42 -0400 (Sat, 16 Oct 2004)
 *          $
 * @since Struts 1.1
 */
public class NestedPropertyTag extends BodyTagSupport
    implements NestedNameSupport {
    /* the usual private member variable */
    private String property = null;
    private String originalNest = null;
    private String originalName = null;
    private String originalProperty = null;

    public String getName() {
        return null;
    }

    public void setName(String newNamed) {
    }

    /**
     * Getter method for the <i>property</i> property
     *
     * @return String value of the property property
     */
    public String getProperty() {
        return this.property;
    }

    /**
     * Setter method for the <i>property</i> property Also, only setting the
     * original property value to those values not set by the nested logic.
     *
     * @param newProperty new value for the property property
     */
    public void setProperty(String newProperty) {
        property = newProperty;
    }

    /**
     * Overriding method of the heart of the tag. Gets the relative property
     * and tells the JSP engine to evaluate its body content.
     *
     * @return int JSP continuation directive.
     */
    public int doStartTag() throws JspException {
        originalProperty = property;

        HttpServletRequest request =
            (HttpServletRequest) pageContext.getRequest();

        originalNest = NestedPropertyHelper.getCurrentProperty(request);
        originalName = NestedPropertyHelper.getCurrentName(request, this);

        String nested =
            NestedPropertyHelper.getAdjustedProperty(request, originalProperty);

        NestedPropertyHelper.setProperty(request, nested);
        NestedPropertyHelper.setName(request, originalName);

        // run the body part
        return (EVAL_BODY_TAG);
    }

    /**
     * Render the resulting content evaluation.
     *
     * @return int JSP continuation directive.
     */
    public int doAfterBody() throws JspException {
        /* Render the output */
        if (bodyContent != null) {
            TagUtils.getInstance().writePrevious(pageContext,
                bodyContent.getString());
            bodyContent.clearBody();
        }

        return (SKIP_BODY);
    }

    /**
     * Evaluate the rest of the page
     *
     * @return int JSP continuation directive.
     */
    public int doEndTag() throws JspException {
        /* set the reference back */
        HttpServletRequest request =
            (HttpServletRequest) pageContext.getRequest();

        if ((originalNest == null) && (originalName == null)) {
            NestedPropertyHelper.deleteReference(request);
        } else {
            NestedPropertyHelper.setName(request, originalName);
            NestedPropertyHelper.setProperty(request, originalNest);
        }

        property = originalProperty;

        return (EVAL_PAGE);
    }

    /**
     * JSP method to release all resources held by the tag.
     */
    public void release() {
        super.release();
        this.property = null;
        this.originalNest = null;
        this.originalName = null;
        this.originalProperty = null;
    }
}