UrlTag.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 net.sourceforge.stripes.exception.StripesJspException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTag;
import java.io.IOException;

/**
 * <p>A Stripes version of the {@literal <c:url/>} tag that adds some Stripes specific
 * parameters to the URL.  Designed to generate URLs and either write them into the page
 * or set them into one of the JSP scopes.</p>
 *
 * <p>Cooperates with the Stripes ParamTag to accept any number of parameters that will be
 * merged into the URL before rendering.</p>
 *
 * @author Tim Fennell
 * @since Stripes 1.4
 * @see ParamTag
 */
public class UrlTag extends LinkTagSupport implements BodyTag {
    String var;
    String scope;

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

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

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

    /**
     * Generates the URL and either writes it into the page or sets it in the appropraite
     * JSP scope.
     *
     * @return {@link #EVAL_PAGE} in all cases.
     * @throws JspException if the output stream cannot be written to.
     */
    @Override
    public int doEndTag() throws JspException {
        String url = buildUrl();

        // If the user specified a 'var', then set the url as a scoped variable
        if (var != null) {
            String s = (this.scope) == null ? "page" : this.scope;

            if (s.equalsIgnoreCase("request")) {
                getPageContext().getRequest().setAttribute(this.var, url);
            }
            else if (s.equalsIgnoreCase("session")) {
                getPageContext().getSession().setAttribute(this.var, url);
            }
            else if (s.equalsIgnoreCase("application")) {
                getPageContext().getServletContext().setAttribute(this.var, url);
            }
            else {
                getPageContext().setAttribute(this.var, url);
            }

        }
        // Else just write it out to the page
        else {
            try { getPageContext().getOut().write(url); }
            catch (IOException ioe) {
                throw new StripesJspException("IOException while trying to write url to page.", ioe);
            }
        }

        clearParameters();

        return EVAL_PAGE;
    }

    /** Gets the name of the scoped variable to store the URL in. */
    public String getVar() { return var; }
    /** Sets the name of the scoped variable to store the URL in. */
    public void setVar(String var) { this.var = var; }

    /** Gets the name of scope to store the scoped variable specified by 'var' in. */
    public String getScope() { return scope; }
    /** Sets the name of scope to store the scoped variable specified by 'var' in. */
    public void setScope(String scope) { this.scope = scope; }

    /** Gets the URL as supplied on the page. */
    public String getValue() { return getUrl(); }
    /** Sets the URL as supplied on the page. */
    public void setValue(String value) { setUrl(value); }
}