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Tomcat example source code file (Import.java)

This example Tomcat source code file (Import.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

context, jspexception, jspexception, jsptagexception, jsptagexception, relative, requestdispatcher, string, string, stringbuffer, unable, url, url, verify

The Tomcat Import.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 Import implements TagPlugin {
    
    public void doTag(TagPluginContext ctxt) {
        boolean hasContext, hasVar, hasScope, hasVarReader, hasCharEncoding;
        
        //flags
        hasContext  = ctxt.isAttributeSpecified("context");
        hasVar = ctxt.isAttributeSpecified("var");
        hasScope = ctxt.isAttributeSpecified("scope");
        hasVarReader = ctxt.isAttributeSpecified("varReader");
        hasCharEncoding = ctxt.isAttributeSpecified("charEncoding");
        
        //variables' names
        String urlName = ctxt.getTemporaryVariableName();           
        String contextName = ctxt.getTemporaryVariableName();       
        String iauName = ctxt.getTemporaryVariableName();           // is absolute url
        String urlObjName = ctxt.getTemporaryVariableName();        //URL object
        String ucName = ctxt.getTemporaryVariableName();            //URLConnection
        String inputStreamName = ctxt.getTemporaryVariableName();   
        String tempReaderName = ctxt.getTemporaryVariableName();
        String tempReaderName2 = ctxt.getTemporaryVariableName();
        String charSetName = ctxt.getTemporaryVariableName();
        String charEncodingName = ctxt.getTemporaryVariableName();
        String contentTypeName = ctxt.getTemporaryVariableName();
        String varReaderName = ctxt.getTemporaryVariableName();
        String servletContextName = ctxt.getTemporaryVariableName();
        String servletPathName = ctxt.getTemporaryVariableName();
        String requestDispatcherName = ctxt.getTemporaryVariableName();
        String irwName = ctxt.getTemporaryVariableName();           //ImportResponseWrapper name
        String brName = ctxt.getTemporaryVariableName();            //BufferedReader name
        String sbName = ctxt.getTemporaryVariableName();            //StringBuffer name
        String tempStringName = ctxt.getTemporaryVariableName();
        
        //is absolute url
        ctxt.generateJavaSource("boolean " + iauName + ";");
        
        //get the url value
        ctxt.generateJavaSource("String " + urlName + " = ");
        ctxt.generateAttribute("url");
        ctxt.generateJavaSource(";");
        
        //validate the url
        ctxt.generateJavaSource("if(" + urlName + " == null || " + urlName + ".equals(\"\")){");
        ctxt.generateJavaSource("    throw new JspTagException(\"The \\\"url\\\" attribute " +
        "illegally evaluated to \\\"null\\\" or \\\"\\\" in <import>\");");
        ctxt.generateJavaSource("}");
        
        //initialize the is_absolute_url
        ctxt.generateJavaSource(iauName + " = " +
                "org.apache.jasper.tagplugins.jstl.Util.isAbsoluteUrl(" + urlName + ");");
        
        //validate the context
        if(hasContext){
            
            ctxt.generateJavaSource("String " + contextName + " = ");
            ctxt.generateAttribute("context");
            ctxt.generateJavaSource(";");
            
            ctxt.generateJavaSource("if((!" + contextName + ".startsWith(\"/\")) " +
                    "|| (!" + urlName + ".startsWith(\"/\"))){");
            ctxt.generateJavaSource("    throw new JspTagException" +
                    "(\"In URL tags, when the \\\"context\\\" attribute is specified, " +
            "values of both \\\"context\\\" and \\\"url\\\" must start with \\\"/\\\".\");");
            ctxt.generateJavaSource("}");
            
        }
        
        //define charset
        ctxt.generateJavaSource("String " + charSetName + " = null;");
        
        //if the charEncoding attribute is specified
        if(hasCharEncoding){
            
            //initialize the charEncoding
            ctxt.generateJavaSource("String " + charEncodingName + " = ");
            ctxt.generateAttribute("charEncoding");
            ctxt.generateJavaSource(";");
            
            //assign appropriate value tp the charset
            ctxt.generateJavaSource("if(null != " + charEncodingName + " " +
                    "&& !" + charEncodingName + ".equals(\"\")){");
            ctxt.generateJavaSource("    " + charSetName + " = " 
                    + charEncodingName + ";");
            ctxt.generateJavaSource("}");
        }
        
        //reshape the url string
        ctxt.generateJavaSource("if(!"+iauName+"){");
        ctxt.generateJavaSource("    if(!" + urlName + ".startsWith(\"/\")){");
        ctxt.generateJavaSource("        String " + servletPathName + " = " +
        "((HttpServletRequest)pageContext.getRequest()).getServletPath();");
        ctxt.generateJavaSource("        " + urlName + " = " 
                + servletPathName + ".substring(0," + servletPathName + ".lastIndexOf('/')) + '/' + " + urlName + ";");
        ctxt.generateJavaSource("    }");
        ctxt.generateJavaSource("}");
        
        //if the varReader attribute specified
        if(hasVarReader){
            
            //get the String value of varReader
            ctxt.generateJavaSource("String " + varReaderName + " = ");
            ctxt.generateAttribute("varReader");
            ctxt.generateJavaSource(";");
            
            //if the url is absolute url
            ctxt.generateJavaSource("if(" + iauName + "){");
            
            //get the content of the target
            ctxt.generateJavaSource("    java.net.URL " + urlObjName + " = new java.net.URL(" + urlName + ");");
            ctxt.generateJavaSource("    java.net.URLConnection " + ucName + " = " 
                    + urlObjName + ".openConnection();");
            ctxt.generateJavaSource("    java.io.InputStream " + inputStreamName + " = " 
                    + ucName + ".getInputStream();");
            
            ctxt.generateJavaSource("    if(" + charSetName + " == null){");
            ctxt.generateJavaSource("        String " + contentTypeName + " = " 
                    + ucName + ".getContentType();");
            ctxt.generateJavaSource("        if(null != " + contentTypeName + "){");
            ctxt.generateJavaSource("            " + charSetName + " = " +
                    "org.apache.jasper.tagplugins.jstl.Util.getContentTypeAttribute(" + contentTypeName + ", \"charset\");");
            ctxt.generateJavaSource("            if(" + charSetName + " == null) " 
                    + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("        }else{");
            ctxt.generateJavaSource("            " + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("        }");
            ctxt.generateJavaSource("    }");
            
            if(!hasCharEncoding){
                ctxt.generateJavaSource("    String " + contentTypeName + " = " + ucName + ".getContentType();");
            }
            
            //define the Reader
            ctxt.generateJavaSource("    java.io.Reader " + tempReaderName + " = null;");
            
            //initialize the Reader object
            ctxt.generateJavaSource("    try{");
            ctxt.generateJavaSource("        " + tempReaderName + " = new java.io.InputStreamReader(" + inputStreamName + ", " + charSetName + ");");
            ctxt.generateJavaSource("    }catch(Exception ex){");
            ctxt.generateJavaSource("        " + tempReaderName + " = new java.io.InputStreamReader(" + inputStreamName + ", org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING);");
            ctxt.generateJavaSource("    }");
            
            //validate the response
            ctxt.generateJavaSource("    if(" + ucName + " instanceof java.net.HttpURLConnection){");
            ctxt.generateJavaSource("        int status = ((java.net.HttpURLConnection) " + ucName + ").getResponseCode();");
            ctxt.generateJavaSource("        if(status < 200 || status > 299){");
            ctxt.generateJavaSource("            throw new JspTagException(status + \" \" + " + urlName + ");");
            ctxt.generateJavaSource("        }");
            ctxt.generateJavaSource("    }");
            
            //set attribute in the page context scope
            ctxt.generateJavaSource("    pageContext.setAttribute(" + varReaderName + ", " + tempReaderName + ");");
            
            //if the url is relative
            ctxt.generateJavaSource("}else{");
            
            //if the url is relative, http request is needed
            ctxt.generateJavaSource("    if (!(pageContext.getRequest() instanceof HttpServletRequest  " +
            "&& pageContext.getResponse() instanceof HttpServletResponse)){");
            ctxt.generateJavaSource("        throw new JspTagException(\"Relative <import> from non-HTTP request not allowed\");");
            ctxt.generateJavaSource("    }");
            
            //get the servlet context of the context defined in the context attribute
            ctxt.generateJavaSource("    ServletContext " + servletContextName + " = null;");
            if(hasContext){
                ctxt.generateJavaSource("    if(null != " + contextName + "){");
                ctxt.generateJavaSource("        " + servletContextName + " = pageContext.getServletContext().getContext(" + contextName + ");" );
                ctxt.generateJavaSource("    }else{");
                ctxt.generateJavaSource("        " + servletContextName + " = pageContext.getServletContext();");
                ctxt.generateJavaSource("    }");
            }else{
                ctxt.generateJavaSource("    " + servletContextName + " = pageContext.getServletContext();");
            }
            
            //
            ctxt.generateJavaSource("    if(" + servletContextName + " == null){");
            if(hasContext){
                ctxt.generateJavaSource("        throw new JspTagException(\"Unable to get RequestDispatcher for Context: \\\" \"+" + contextName + "+\" \\\" and URL: \\\" \" +" + urlName + "+ \" \\\". Verify values and/or enable cross context access.\");");
            }else{
                ctxt.generateJavaSource("        throw new JspTagException(\"Unable to get RequestDispatcher for  URL: \\\" \" +" + urlName + "+ \" \\\". Verify values and/or enable cross context access.\");");
            }
            ctxt.generateJavaSource("    }");
            
            //get the request dispatcher
            ctxt.generateJavaSource("    RequestDispatcher " + requestDispatcherName + " = " + servletContextName + ".getRequestDispatcher(org.apache.jasper.tagplugins.jstl.Util.stripSession("+urlName+"));");
            ctxt.generateJavaSource("    if(" + requestDispatcherName + " == null) throw new JspTagException(org.apache.jasper.tagplugins.jstl.Util.stripSession("+urlName+"));");
            
            //initialize a ImportResponseWrapper to include the resource
            ctxt.generateJavaSource("    org.apache.jasper.tagplugins.jstl.Util.ImportResponseWrapper " + irwName + " = new org.apache.jasper.tagplugins.jstl.Util.ImportResponseWrapper((HttpServletResponse) pageContext.getResponse());");
            ctxt.generateJavaSource("    if(" + charSetName + " == null){");
            ctxt.generateJavaSource("        " + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("    }");
            ctxt.generateJavaSource("    " + irwName + ".setCharEncoding(" + charSetName + ");");
            ctxt.generateJavaSource("    try{");
            ctxt.generateJavaSource("        " + requestDispatcherName + ".include(pageContext.getRequest(), " + irwName + ");");
            ctxt.generateJavaSource("    }catch(java.io.IOException ex){");
            ctxt.generateJavaSource("        throw new JspException(ex);");
            ctxt.generateJavaSource("    }catch(RuntimeException ex){");
            ctxt.generateJavaSource("        throw new JspException(ex);");
            ctxt.generateJavaSource("    }catch(ServletException ex){");
            ctxt.generateJavaSource("        Throwable rc = ex.getRootCause();");
            ctxt.generateJavaSource("        if (rc == null)");
            ctxt.generateJavaSource("            throw new JspException(ex);");
            ctxt.generateJavaSource("        else");
            ctxt.generateJavaSource("            throw new JspException(rc);");
            ctxt.generateJavaSource("    }");
            
            //validate the response status
            ctxt.generateJavaSource("    if(" + irwName + ".getStatus() < 200 || " + irwName + ".getStatus() > 299){");
            ctxt.generateJavaSource("        throw new JspTagException(" + irwName + ".getStatus()+\" \" + org.apache.jasper.tagplugins.jstl.Util.stripSession(" + urlName + "));");
            ctxt.generateJavaSource("    }");
            
            //push in the page context
            ctxt.generateJavaSource("    java.io.Reader " + tempReaderName + " = new java.io.StringReader(" + irwName + ".getString());");
            ctxt.generateJavaSource("    pageContext.setAttribute(" + varReaderName + ", " + tempReaderName + ");");
            
            ctxt.generateJavaSource("}");
            
            //execute the body action
            ctxt.generateBody();
            
            //close the reader
            ctxt.generateJavaSource("java.io.Reader " + tempReaderName2 + " = (java.io.Reader)pageContext.getAttribute(" + varReaderName + ");");
            ctxt.generateJavaSource("if(" + tempReaderName2 + " != null) " + tempReaderName2 + ".close();");
            ctxt.generateJavaSource("pageContext.removeAttribute(" + varReaderName + ",1);");
        }
        
        //if the varReader is not specified 
        else{
            
            ctxt.generateJavaSource("pageContext.setAttribute(\"url_without_param\"," + urlName + ");");
            ctxt.generateBody();
            ctxt.generateJavaSource(urlName + " = (String)pageContext.getAttribute(\"url_without_param\");");
            ctxt.generateJavaSource("pageContext.removeAttribute(\"url_without_param\");");
            String strScope = "page";
            if(hasScope){
                strScope = ctxt.getConstantAttribute("scope");
            }
            int iScope = Util.getScope(strScope);
            
            ctxt.generateJavaSource("String " + tempStringName + " = null;");
            
            ctxt.generateJavaSource("if(" + iauName + "){");
            
            //get the content of the target
            ctxt.generateJavaSource("    java.net.URL " + urlObjName + " = new java.net.URL(" + urlName + ");");
            ctxt.generateJavaSource("    java.net.URLConnection " + ucName + " = " + urlObjName + ".openConnection();");
            ctxt.generateJavaSource("    java.io.InputStream " + inputStreamName + " = " + ucName + ".getInputStream();");
            ctxt.generateJavaSource("    java.io.Reader " + tempReaderName + " = null;");
            
            ctxt.generateJavaSource("    if(" + charSetName + " == null){");
            ctxt.generateJavaSource("        String " + contentTypeName + " = " 
                    + ucName + ".getContentType();");
            ctxt.generateJavaSource("        if(null != " + contentTypeName + "){");
            ctxt.generateJavaSource("            " + charSetName + " = " +
                    "org.apache.jasper.tagplugins.jstl.Util.getContentTypeAttribute(" + contentTypeName + ", \"charset\");");
            ctxt.generateJavaSource("            if(" + charSetName + " == null) " 
                    + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("        }else{");
            ctxt.generateJavaSource("            " + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("        }");
            ctxt.generateJavaSource("    }");
            
            ctxt.generateJavaSource("    try{");
            ctxt.generateJavaSource("        " + tempReaderName + " = new java.io.InputStreamReader(" + inputStreamName + "," + charSetName + ");");
            ctxt.generateJavaSource("    }catch(Exception ex){");
            //ctxt.generateJavaSource("        throw new JspTagException(ex.toString());");
            ctxt.generateJavaSource("        " + tempReaderName + " = new java.io.InputStreamReader(" + inputStreamName + ",org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING);");
            ctxt.generateJavaSource("    }");
            
            //validate the response
            ctxt.generateJavaSource("    if(" + ucName + " instanceof java.net.HttpURLConnection){");
            ctxt.generateJavaSource("        int status = ((java.net.HttpURLConnection) " + ucName + ").getResponseCode();");
            ctxt.generateJavaSource("        if(status < 200 || status > 299){");
            ctxt.generateJavaSource("            throw new JspTagException(status + \" \" + " + urlName + ");");
            ctxt.generateJavaSource("        }");
            ctxt.generateJavaSource("    }");
            
            ctxt.generateJavaSource("    java.io.BufferedReader " + brName + " =  new java.io.BufferedReader(" + tempReaderName + ");");
            ctxt.generateJavaSource("    StringBuffer " + sbName + " = new StringBuffer();");
            String index = ctxt.getTemporaryVariableName();
            ctxt.generateJavaSource("    int " + index + ";");
            ctxt.generateJavaSource("    while(("+index+" = "+brName+".read()) != -1) "+sbName+".append((char)"+index+");");
            ctxt.generateJavaSource("    " + tempStringName + " = " +sbName + ".toString();");
            
            ctxt.generateJavaSource("}else{");
            
            //if the url is relative, http request is needed.
            ctxt.generateJavaSource("    if (!(pageContext.getRequest() instanceof HttpServletRequest  " +
            "&& pageContext.getResponse() instanceof HttpServletResponse)){");
            ctxt.generateJavaSource("        throw new JspTagException(\"Relative <import> from non-HTTP request not allowed\");");
            ctxt.generateJavaSource("    }");
            
            //get the servlet context of the context defined in the context attribute
            ctxt.generateJavaSource("    ServletContext " + servletContextName + " = null;");
            if(hasContext){
                ctxt.generateJavaSource("    if(null != " + contextName + "){");
                ctxt.generateJavaSource("        " + servletContextName + " = pageContext.getServletContext().getContext(" + contextName + ");" );
                ctxt.generateJavaSource("    }else{");
                ctxt.generateJavaSource("        " + servletContextName + " = pageContext.getServletContext();");
                ctxt.generateJavaSource("    }");
            }else{
                ctxt.generateJavaSource("    " + servletContextName + " = pageContext.getServletContext();");
            }
            
            //
            ctxt.generateJavaSource("    if(" + servletContextName + " == null){");
            if(hasContext){
                ctxt.generateJavaSource("        throw new JspTagException(\"Unable to get RequestDispatcher for Context: \\\" \" +" + contextName + "+ \" \\\" and URL: \\\" \" +" + urlName + "+ \" \\\". Verify values and/or enable cross context access.\");");
            }else{
                ctxt.generateJavaSource("        throw new JspTagException(\"Unable to get RequestDispatcher for URL: \\\" \" +" + urlName + "+ \" \\\". Verify values and/or enable cross context access.\");");
            }
            ctxt.generateJavaSource("    }");
            
            //get the request dispatcher
            ctxt.generateJavaSource("    RequestDispatcher " + requestDispatcherName + " = " + servletContextName + ".getRequestDispatcher(org.apache.jasper.tagplugins.jstl.Util.stripSession("+urlName+"));");
            ctxt.generateJavaSource("    if(" + requestDispatcherName + " == null) throw new JspTagException(org.apache.jasper.tagplugins.jstl.Util.stripSession("+urlName+"));");
            
            //initialize a ImportResponseWrapper to include the resource
            ctxt.generateJavaSource("    org.apache.jasper.tagplugins.jstl.Util.ImportResponseWrapper " + irwName + " = new org.apache.jasper.tagplugins.jstl.Util.ImportResponseWrapper((HttpServletResponse) pageContext.getResponse());");
            ctxt.generateJavaSource("    if(" + charSetName + " == null){");
            ctxt.generateJavaSource("        " + charSetName + " = org.apache.jasper.tagplugins.jstl.Util.DEFAULT_ENCODING;");
            ctxt.generateJavaSource("    }");
            ctxt.generateJavaSource("    " + irwName + ".setCharEncoding(" + charSetName + ");");
            ctxt.generateJavaSource("    try{");
            ctxt.generateJavaSource("        " + requestDispatcherName + ".include(pageContext.getRequest(), " + irwName + ");");
            ctxt.generateJavaSource("    }catch(java.io.IOException ex){");
            ctxt.generateJavaSource("        throw new JspException(ex);");
            ctxt.generateJavaSource("    }catch(RuntimeException ex){");
            ctxt.generateJavaSource("        throw new JspException(ex);");
            ctxt.generateJavaSource("    }catch(ServletException ex){");
            ctxt.generateJavaSource("        Throwable rc = ex.getRootCause();");
            ctxt.generateJavaSource("        if (rc == null)");
            ctxt.generateJavaSource("            throw new JspException(ex);");
            ctxt.generateJavaSource("        else");
            ctxt.generateJavaSource("            throw new JspException(rc);");
            ctxt.generateJavaSource("    }");
            
            //validate the response status
            ctxt.generateJavaSource("    if(" + irwName + ".getStatus() < 200 || " + irwName + ".getStatus() > 299){");
            ctxt.generateJavaSource("        throw new JspTagException(" + irwName + ".getStatus()+\" \" + org.apache.jasper.tagplugins.jstl.Util.stripSession(" + urlName + "));");
            ctxt.generateJavaSource("    }");
            
            ctxt.generateJavaSource("    " + tempStringName + " = " + irwName + ".getString();");
            
            ctxt.generateJavaSource("}");
            
            if(hasVar){
                String strVar = ctxt.getConstantAttribute("var");
                ctxt.generateJavaSource("pageContext.setAttribute(\""+strVar+"\"," + tempStringName + "," + iScope + ");");
            }else{
                ctxt.generateJavaSource("pageContext.getOut().print(" + tempStringName + ");");
            }
        }
    }
    
    
    
}

Other Tomcat examples (source code examples)

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