LinkTag.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;

/**
 * Tag for generating links to pages or ActionBeans within a Stripes application. Provides
 * basic services such as including the context path at the start of the href URL (only
 * when the URL starts with a '/' and does not contain the context path already), and
 * including a parameter to name the source page from which the link came. Also provides the
 * ability to add complex parameters to the URL through the use of nested Param tags.
 *
 * @see ParamTag
 * @author Tim Fennell
 */
public class LinkTag extends LinkTagSupport implements BodyTag {

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

    /**
     * Prepends the context to the href attribute if necessary, and then folds all the
     * registered parameters into the URL.
     *
     * @return EVAL_PAGE in all cases
     * @throws JspException
     */
    @Override
    public int doEndTag() throws JspException {
        try {
            set("href", buildUrl());
            writeOpenTag(getPageContext().getOut(), "a");
            String body = getBodyContentAsString();
            if (body == null || body.trim().length() == 0) {
                body = get("href");
            }
            if (body != null) {
                getPageContext().getOut().write(body.trim());
            }
            writeCloseTag(getPageContext().getOut(), "a");
        }
        catch (IOException ioe) {
            throw new StripesJspException("IOException while writing output in LinkTag.", ioe);
        }

        // Restore state and go on with the page
        getAttributes().remove("href");
        clearParameters();
        return EVAL_PAGE;
    }

    /** Pass through to {@link LinkTagSupport#setUrl(String)}. */
    public void   setHref(String href) { setUrl(href); }
    /** Pass through to {@link LinkTagSupport#getUrl()}. */
    public String getHref() { return getUrl(); }


    ///////////////////////////////////////////////////////////////////////////
    // Additional HTML Attributes supported by the tag
    ///////////////////////////////////////////////////////////////////////////
    public void   setCharset(String charset) { set("charset", charset); }
    public String getCharset() { return get("charset"); }

    public void   setCoords(String coords) { set("coords", coords); }
    public String getCoords() { return get("coords"); }

    public void   setHreflang(String hreflang) { set("hreflang", hreflang); }
    public String getHreflang() { return get("hreflang"); }

    public void   setName(String name) { set("name", name); }
    public String getName() { return get("name"); }

    public void   setRel(String rel) { set("rel", rel); }
    public String getRel() { return get("rel"); }

    public void   setRev(String rev) { set("rev", rev); }
    public String getRev() { return get("rev"); }

    public void   setShape(String shape) { set("shape", shape); }
    public String getShape() { return get("shape"); }

    public void   setTarget(String target) { set("target", target); }
    public String getTarget() { return get("target"); }

    public void   setType(String type) { set("type", type); }
    public String getType() { return get("type"); }
}