alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Tomcat example source code file (Url.java)

This example Tomcat source code file (Url.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

httpservletresponse, httpservletresponse, string, string, tagplugin, tagplugin, url, url

The Tomcat Url.java source code

/*
 * 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.jasper.tagplugins.jstl.core;

import org.apache.jasper.compiler.tagplugin.TagPlugin;
import org.apache.jasper.compiler.tagplugin.TagPluginContext;
import org.apache.jasper.tagplugins.jstl.Util;

public class Url implements TagPlugin {
    
    public void doTag(TagPluginContext ctxt) {
        
        //flags
        boolean hasVar, hasContext, hasScope;
        
        //init flags
        hasVar = ctxt.isAttributeSpecified("var");
        hasContext = ctxt.isAttributeSpecified("context");
        hasScope = ctxt.isAttributeSpecified("scope");
        
        //define name of the temp variables
        String valueName = ctxt.getTemporaryVariableName();
        String contextName = ctxt.getTemporaryVariableName();
        String baseUrlName = ctxt.getTemporaryVariableName();
        String resultName = ctxt.getTemporaryVariableName();
        String responseName = ctxt.getTemporaryVariableName();
        
        //get the scope
        String strScope = "page";
        if(hasScope){
            strScope = ctxt.getConstantAttribute("scope");
        }
        int iScope = Util.getScope(strScope);
        
        //get the value
        ctxt.generateJavaSource("String " + valueName + " = ");
        ctxt.generateAttribute("value");
        ctxt.generateJavaSource(";");
        
        //get the context
        ctxt.generateJavaSource("String " + contextName + " = null;");
        if(hasContext){
            ctxt.generateJavaSource(contextName + " = ");
            ctxt.generateAttribute("context");
            ctxt.generateJavaSource(";");
        }
        
        //get the raw url
        ctxt.generateJavaSource("String " + baseUrlName + " = " +
                "org.apache.jasper.tagplugins.jstl.Util.resolveUrl(" + valueName + ", " + contextName + ", pageContext);");
        ctxt.generateJavaSource("pageContext.setAttribute" +
                "(\"url_without_param\", " + baseUrlName + ");");
        
        //add params
        ctxt.generateBody();
        
        ctxt.generateJavaSource("String " + resultName + " = " +
        "(String)pageContext.getAttribute(\"url_without_param\");");
        ctxt.generateJavaSource("pageContext.removeAttribute(\"url_without_param\");");
        
        //if the url is relative, encode it
        ctxt.generateJavaSource("if(!org.apache.jasper.tagplugins.jstl.Util.isAbsoluteUrl(" + resultName + ")){");
        ctxt.generateJavaSource("    HttpServletResponse " + responseName + " = " +
        "((HttpServletResponse) pageContext.getResponse());");
        ctxt.generateJavaSource("    " + resultName + " = "
                + responseName + ".encodeURL(" + resultName + ");");
        ctxt.generateJavaSource("}");
        
        //if "var" is specified, the url string store in the attribute var defines
        if(hasVar){
            String strVar = ctxt.getConstantAttribute("var");
            ctxt.generateJavaSource("pageContext.setAttribute" +
                    "(\"" + strVar + "\", " + resultName + ", " + iScope + ");");
            
            //if var is not specified, just print out the url string
        }else{
            ctxt.generateJavaSource("try{");
            ctxt.generateJavaSource("    pageContext.getOut().print(" + resultName + ");");
            ctxt.generateJavaSource("}catch(java.io.IOException ex){");
            ctxt.generateJavaSource("    throw new JspTagException(ex.toString(), ex);");
            ctxt.generateJavaSource("}");
        }
    }
    
}

Other Tomcat examples (source code examples)

Here is a short list of links related to this Tomcat Url.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.