ParamTag.java

/* Copyright 2005-2006 Tim Fennell
 *
 * 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 net.sourceforge.stripes.tag;

import javax.servlet.jsp.tagext.BodyTag;
import javax.servlet.jsp.tagext.BodyContent;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.JspException;

/**
 * <p>Used to supply parameters when nested inside tags that implement {@link ParameterizableTag}.
 * The value is either obtained from the value attribute, or if that is not present, then the
 * body of the tag.</p>
 *
 * <p>Once the value has been established the parent tag is looked for, and the parameter is handed
 * over to it.</p>
 *
 * <p>Primarily used by the LinkTag and UrlTag.</p>

 * @author Tim Fennell
 * @since Stripes 1.4
 * @see ParamTag
 */
public class ParamTag implements BodyTag {
    private String name;
    private Object value;
    private BodyContent bodyContent;
    private Tag parentTag;
    private PageContext pageContext;

    /** Sets the value of the parameter(s) to be added to the URL. */
    public void setValue(Object value) {
        this.value = value;
    }

    /** Gets the value attribute, as set with setValue(). */
    public Object getValue() {
        return value;
    }

    /** Sets the name of the parameter(s) that will be added to the URL. */
    public void setName(String name) {
        this.name = name;
    }

    /** Gets the name of the parameter(s) that will be added to the URL. */
    public String getName() {
        return name;
    }

    /** Used by the container to set the contents of the body of the tag. */
    public void setBodyContent(BodyContent bodyContent) {
        this.bodyContent = bodyContent;
    }

    /** Used by the container to set the page context for the tag. */
    public void setPageContext(PageContext pageContext) {
        this.pageContext = pageContext;
    }

    /** Used by the container to provide the tag with access to its parent tag on the page. */
    public void setParent(Tag tag) {
        this.parentTag = tag;
    }

    /** Required spec method to allow others to access the parent of the tag. */
    public Tag getParent() {
        return this.parentTag;
    }

    /** Does nothing. */
    public void doInitBody() throws JspException { /* Do Nothing */ }

    /**
     * Does nothing.
     * @return SKIP_BODY in all cases.
     */
    public int doAfterBody() throws JspException { return SKIP_BODY; }

    /**
     * Does nothing.
     * @return EVAL_BODY_BUFFERED in all cases.
     */
    public int doStartTag() throws JspException { return EVAL_BODY_BUFFERED; }

    /**
     * Figures out what to use as the value, and then finds the parent link and adds
     * the parameter.
     * @return EVAL_PAGE in all cases.
     */
    public int doEndTag() throws JspException {
        Object valueToSet = value;

        // First figure out what value to send to the parent link tag
        if (value == null) {
            if (this.bodyContent == null) {
                valueToSet = "";
            }
            else {
                valueToSet = this.bodyContent.getString();
            }
        }

        // Find the parent link tag
        Tag parameterizable = this.parentTag;
        while (parameterizable != null && !(parameterizable instanceof ParameterizableTag)) {
            parameterizable = parameterizable.getParent();
        }

        ((ParameterizableTag) parameterizable).addParameter(name, valueToSet);
        return EVAL_PAGE;
    }

    /** Does nothing. */
    public void release() { /* Do nothing. */ }

	public PageContext getPageContext()
	{
		return pageContext;
	}
}