Struts example source code file (JspConfig.java)

This example Struts source code file (JspConfig.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 - Struts tags/keywords

inputsource, io, iterator, jasperexception, jspconfig, jspproperty, jspproperty, jsppropertygroup, jsppropertygroup, net, network, parserutils, sax, servlet, string, string, treenode, util, vector, vector

The Struts JspConfig.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.struts2.jasper.compiler;

import java.io.InputStream;
import java.util.Iterator;
import java.util.Vector;
import java.net.URL;

import javax.servlet.ServletContext;

import org.apache.struts2.jasper.JasperException;
import org.apache.struts2.jasper.xmlparser.ParserUtils;
import org.apache.struts2.jasper.xmlparser.TreeNode;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.xml.sax.InputSource;

/**
 * Handles the jsp-config element in WEB_INF/web.xml.  This is used
 * for specifying the JSP configuration information on a JSP page
 *
 * @author Kin-man Chung
 * @author Remy Maucherat
 */

public class JspConfig {

    private static final String WEB_XML = "/WEB-INF/web.xml";

    // Logger
    private Log log = LogFactory.getLog(JspConfig.class);

    private Vector jspProperties = null;
    private ServletContext ctxt;
    private boolean initialized = false;

    private String defaultIsXml = null;		// unspecified
    private String defaultIsELIgnored = null;	// unspecified
    private String defaultIsScriptingInvalid = null;
    private String defaultDeferedSyntaxAllowedAsLiteral = null;
    private String defaultTrimDirectiveWhitespaces = null;
    private JspProperty defaultJspProperty;

    public JspConfig(ServletContext ctxt) {
        this.ctxt = ctxt;
    }

    private double getVersion(TreeNode webApp) {
        String v = webApp.findAttribute("version");
        if (v != null) {
            try {
                return Double.parseDouble(v);
            } catch (NumberFormatException e) {
            }
        }
        return 2.3;
    }

    private void processWebDotXml(ServletContext ctxt) throws JasperException {

        InputStream is = null;

        try {
            URL uri = ctxt.getResource(WEB_XML);
            if (uri == null) {
                // no web.xml
                return;
            }

            is = uri.openStream();
            InputSource ip = new InputSource(is);
            ip.setSystemId(uri.toExternalForm()); 

            ParserUtils pu = new ParserUtils();
            TreeNode webApp = pu.parseXMLDocument(WEB_XML, ip);

            if (webApp == null
                    || getVersion(webApp) < 2.4) {
                defaultIsELIgnored = "true";
                return;
            }
            TreeNode jspConfig = webApp.findChild("jsp-config");
            if (jspConfig == null) {
                return;
            }

            jspProperties = new Vector();
            Iterator jspPropertyList = jspConfig.findChildren("jsp-property-group");
            while (jspPropertyList.hasNext()) {

                TreeNode element = (TreeNode) jspPropertyList.next();
                Iterator list = element.findChildren();

                Vector urlPatterns = new Vector();
                String pageEncoding = null;
                String scriptingInvalid = null;
                String elIgnored = null;
                String isXml = null;
                Vector includePrelude = new Vector();
                Vector includeCoda = new Vector();
                String deferredSyntaxAllowedAsLiteral = null;
                String trimDirectiveWhitespaces = null;

                while (list.hasNext()) {

                    element = (TreeNode) list.next();
                    String tname = element.getName();

                    if ("url-pattern".equals(tname))
                        urlPatterns.addElement( element.getBody() );
                    else if ("page-encoding".equals(tname))
                        pageEncoding = element.getBody();
                    else if ("is-xml".equals(tname))
                        isXml = element.getBody();
                    else if ("el-ignored".equals(tname))
                        elIgnored = element.getBody();
                    else if ("scripting-invalid".equals(tname))
                        scriptingInvalid = element.getBody();
                    else if ("include-prelude".equals(tname))
                        includePrelude.addElement(element.getBody());
                    else if ("include-coda".equals(tname))
                        includeCoda.addElement(element.getBody());
                    else if ("deferred-syntax-allowed-as-literal".equals(tname))
                        deferredSyntaxAllowedAsLiteral = element.getBody();
                    else if ("trim-directive-whitespaces".equals(tname))
                        trimDirectiveWhitespaces = element.getBody();
                }

                if (urlPatterns.size() == 0) {
                    continue;
                }

                // Add one JspPropertyGroup for each URL Pattern.  This makes
                // the matching logic easier.
                for( int p = 0; p < urlPatterns.size(); p++ ) {
                    String urlPattern = (String)urlPatterns.elementAt( p );
                    String path = null;
                    String extension = null;

                    if (urlPattern.indexOf('*') < 0) {
                        // Exact match
                        path = urlPattern;
                    } else {
                        int i = urlPattern.lastIndexOf('/');
                        String file;
                        if (i >= 0) {
                            path = urlPattern.substring(0,i+1);
                            file = urlPattern.substring(i+1);
                        } else {
                            file = urlPattern;
                        }

                        // pattern must be "*", or of the form "*.jsp"
                        if (file.equals("*")) {
                            extension = "*";
                        } else if (file.startsWith("*.")) {
                            extension = file.substring(file.indexOf('.')+1);
                        }

                        // The url patterns are reconstructed as the follwoing:
                        // path != null, extension == null:  / or /foo/bar.ext
                        // path == null, extension != null:  *.ext
                        // path != null, extension == "*":   /foo/*
                        boolean isStar = "*".equals(extension);
                        if ((path == null && (extension == null || isStar))
                                || (path != null && !isStar)) {
                            if (log.isWarnEnabled()) {
                                log.warn(Localizer.getMessage(
                                        "jsp.warning.bad.urlpattern.propertygroup",
                                        urlPattern));
                            }
                            continue;
                        }
                    }

                    JspProperty property = new JspProperty(isXml,
                            elIgnored,
                            scriptingInvalid,
                            pageEncoding,
                            includePrelude,
                            includeCoda,
                            deferredSyntaxAllowedAsLiteral,
                            trimDirectiveWhitespaces);
                    JspPropertyGroup propertyGroup =
                        new JspPropertyGroup(path, extension, property);

                    jspProperties.addElement(propertyGroup);
                }
            }
        } catch (Exception ex) {
            throw new JasperException(ex);
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (Throwable t) {}
            }
        }
    }

    private void init() throws JasperException {

        if (!initialized) {
            processWebDotXml(ctxt);
            defaultJspProperty = new JspProperty(defaultIsXml,
                    defaultIsELIgnored,
                    defaultIsScriptingInvalid,
                    null, null, null, defaultDeferedSyntaxAllowedAsLiteral, 
                    defaultTrimDirectiveWhitespaces);
            initialized = true;
        }
    }

    /**
     * Select the property group that has more restrictive url-pattern.
     * In case of tie, select the first.
     */
    private JspPropertyGroup selectProperty(JspPropertyGroup prev,
            JspPropertyGroup curr) {
        if (prev == null) {
            return curr;
        }
        if (prev.getExtension() == null) {
            // exact match
            return prev;
        }
        if (curr.getExtension() == null) {
            // exact match
            return curr;
        }
        String prevPath = prev.getPath();
        String currPath = curr.getPath();
        if (prevPath == null && currPath == null) {
            // Both specifies a *.ext, keep the first one
            return prev;
        }
        if (prevPath == null && currPath != null) {
            return curr;
        }
        if (prevPath != null && currPath == null) {
            return prev;
        }
        if (prevPath.length() >= currPath.length()) {
            return prev;
        }
        return curr;
    }


    /**
     * Find a property that best matches the supplied resource.
     * @param uri the resource supplied.
     * @return a JspProperty indicating the best match, or some default.
     */
    public JspProperty findJspProperty(String uri) throws JasperException {

        init();

        // JSP Configuration settings do not apply to tag files	    
        if (jspProperties == null || uri.endsWith(".tag")
                || uri.endsWith(".tagx")) {
            return defaultJspProperty;
        }

        String uriPath = null;
        int index = uri.lastIndexOf('/');
        if (index >=0 ) {
            uriPath = uri.substring(0, index+1);
        }
        String uriExtension = null;
        index = uri.lastIndexOf('.');
        if (index >=0) {
            uriExtension = uri.substring(index+1);
        }

        Vector includePreludes = new Vector();
        Vector includeCodas = new Vector();

        JspPropertyGroup isXmlMatch = null;
        JspPropertyGroup elIgnoredMatch = null;
        JspPropertyGroup scriptingInvalidMatch = null;
        JspPropertyGroup pageEncodingMatch = null;
        JspPropertyGroup deferedSyntaxAllowedAsLiteralMatch = null;
        JspPropertyGroup trimDirectiveWhitespacesMatch = null;

        Iterator iter = jspProperties.iterator();
        while (iter.hasNext()) {

            JspPropertyGroup jpg = (JspPropertyGroup) iter.next();
            JspProperty jp = jpg.getJspProperty();

            // (arrays will be the same length)
            String extension = jpg.getExtension();
            String path = jpg.getPath();

            if (extension == null) {
                // exact match pattern: /a/foo.jsp
                if (!uri.equals(path)) {
                    // not matched;
                    continue;
                }
            } else {
                // Matching patterns *.ext or /p/*
                if (path != null && uriPath != null &&
                        ! uriPath.startsWith(path)) {
                    // not matched
                    continue;
                }
                if (!extension.equals("*") &&
                        !extension.equals(uriExtension)) {
                    // not matched
                    continue;
                }
            }
            // We have a match
            // Add include-preludes and include-codas
            if (jp.getIncludePrelude() != null) {
                includePreludes.addAll(jp.getIncludePrelude());
            }
            if (jp.getIncludeCoda() != null) {
                includeCodas.addAll(jp.getIncludeCoda());
            }

            // If there is a previous match for the same property, remember
            // the one that is more restrictive.
            if (jp.isXml() != null) {
                isXmlMatch = selectProperty(isXmlMatch, jpg);
            }
            if (jp.isELIgnored() != null) {
                elIgnoredMatch = selectProperty(elIgnoredMatch, jpg);
            }
            if (jp.isScriptingInvalid() != null) {
                scriptingInvalidMatch =
                    selectProperty(scriptingInvalidMatch, jpg);
            }
            if (jp.getPageEncoding() != null) {
                pageEncodingMatch = selectProperty(pageEncodingMatch, jpg);
            }
            if (jp.isDeferedSyntaxAllowedAsLiteral() != null) {
                deferedSyntaxAllowedAsLiteralMatch =
                    selectProperty(deferedSyntaxAllowedAsLiteralMatch, jpg);
            }
            if (jp.isTrimDirectiveWhitespaces() != null) {
                trimDirectiveWhitespacesMatch =
                    selectProperty(trimDirectiveWhitespacesMatch, jpg);
            }
        }


        String isXml = defaultIsXml;
        String isELIgnored = defaultIsELIgnored;
        String isScriptingInvalid = defaultIsScriptingInvalid;
        String pageEncoding = null;
        String isDeferedSyntaxAllowedAsLiteral = defaultDeferedSyntaxAllowedAsLiteral;
        String isTrimDirectiveWhitespaces = defaultTrimDirectiveWhitespaces;

        if (isXmlMatch != null) {
            isXml = isXmlMatch.getJspProperty().isXml();
        }
        if (elIgnoredMatch != null) {
            isELIgnored = elIgnoredMatch.getJspProperty().isELIgnored();
        }
        if (scriptingInvalidMatch != null) {
            isScriptingInvalid =
                scriptingInvalidMatch.getJspProperty().isScriptingInvalid();
        }
        if (pageEncodingMatch != null) {
            pageEncoding = pageEncodingMatch.getJspProperty().getPageEncoding();
        }
        if (deferedSyntaxAllowedAsLiteralMatch != null) {
            isDeferedSyntaxAllowedAsLiteral =
                deferedSyntaxAllowedAsLiteralMatch.getJspProperty().isDeferedSyntaxAllowedAsLiteral();
        }
        if (trimDirectiveWhitespacesMatch != null) {
            isTrimDirectiveWhitespaces =
                trimDirectiveWhitespacesMatch.getJspProperty().isTrimDirectiveWhitespaces();
        }

        return new JspProperty(isXml, isELIgnored, isScriptingInvalid,
                pageEncoding, includePreludes, includeCodas, 
                isDeferedSyntaxAllowedAsLiteral, isTrimDirectiveWhitespaces);
    }

    /**
     * To find out if an uri matches an url pattern in jsp config.  If so,
     * then the uri is a JSP page.  This is used primarily for jspc.
     */
    public boolean isJspPage(String uri) throws JasperException {

        init();
        if (jspProperties == null) {
            return false;
        }

        String uriPath = null;
        int index = uri.lastIndexOf('/');
        if (index >=0 ) {
            uriPath = uri.substring(0, index+1);
        }
        String uriExtension = null;
        index = uri.lastIndexOf('.');
        if (index >=0) {
            uriExtension = uri.substring(index+1);
        }

        Iterator iter = jspProperties.iterator();
        while (iter.hasNext()) {

            JspPropertyGroup jpg = (JspPropertyGroup) iter.next();
            JspProperty jp = jpg.getJspProperty();

            String extension = jpg.getExtension();
            String path = jpg.getPath();

            if (extension == null) {
                if (uri.equals(path)) {
                    // There is an exact match
                    return true;
                }
            } else {
                if ((path == null || path.equals(uriPath)) &&
                        (extension.equals("*") || extension.equals(uriExtension))) {
                    // Matches *, *.ext, /p/*, or /p/*.ext
                    return true;
                }
            }
        }
        return false;
    }

    static class JspPropertyGroup {
        private String path;
        private String extension;
        private JspProperty jspProperty;

        JspPropertyGroup(String path, String extension,
                JspProperty jspProperty) {
            this.path = path;
            this.extension = extension;
            this.jspProperty = jspProperty;
        }

        public String getPath() {
            return path;
        }

        public String getExtension() {
            return extension;
        }

        public JspProperty getJspProperty() {
            return jspProperty;
        }
    }

    static public class JspProperty {

        private String isXml;
        private String elIgnored;
        private String scriptingInvalid;
        private String pageEncoding;
        private Vector includePrelude;
        private Vector includeCoda;
        private String deferedSyntaxAllowedAsLiteral;
        private String trimDirectiveWhitespaces;

        public JspProperty(String isXml, String elIgnored,
                String scriptingInvalid, String pageEncoding,
                Vector includePrelude, Vector includeCoda,
                String deferedSyntaxAllowedAsLiteral, 
                String trimDirectiveWhitespaces) {

            this.isXml = isXml;
            this.elIgnored = elIgnored;
            this.scriptingInvalid = scriptingInvalid;
            this.pageEncoding = pageEncoding;
            this.includePrelude = includePrelude;
            this.includeCoda = includeCoda;
            this.deferedSyntaxAllowedAsLiteral = deferedSyntaxAllowedAsLiteral;
            this.trimDirectiveWhitespaces = trimDirectiveWhitespaces;
        }

        public String isXml() {
            return isXml;
        }

        public String isELIgnored() {
            return elIgnored;
        }

        public String isScriptingInvalid() {
            return scriptingInvalid;
        }

        public String getPageEncoding() {
            return pageEncoding;
        }

        public Vector getIncludePrelude() {
            return includePrelude;
        }

        public Vector getIncludeCoda() {
            return includeCoda;
        }
        
        public String isDeferedSyntaxAllowedAsLiteral() {
            return deferedSyntaxAllowedAsLiteral;
        }
        
        public String isTrimDirectiveWhitespaces() {
            return trimDirectiveWhitespaces;
        }
    }
}