Tomcat example source code file (SSIMediator.java)

This example Tomcat source code file (SSIMediator.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

date, date, date_gmt, date_local, default_config_err_msg, io, ioexception, ioexception, last_modified, ssiconditionalstate, string, string, timezone, timezone, urlencoder, util

The Tomcat SSIMediator.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.catalina.ssi;


import java.io.IOException;
import java.util.Collection;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.TimeZone;
import org.apache.catalina.util.DateTool;
import org.apache.catalina.util.Strftime;
import org.apache.catalina.util.URLEncoder;
/**
 * Allows the different SSICommand implementations to share data/talk to each
 * other
 * 
 * @author Bip Thelin
 * @author Amy Roh
 * @author Paul Speed
 * @author Dan Sandberg
 * @author David Becker
 * @version $Revision: 531303 $, $Date: 2007-04-23 02:24:01 +0200 (lun., 23 avr. 2007) $
 */
public class SSIMediator {
    protected final static String DEFAULT_CONFIG_ERR_MSG = "[an error occurred while processing this directive]";
    protected final static String DEFAULT_CONFIG_TIME_FMT = "%A, %d-%b-%Y %T %Z";
    protected final static String DEFAULT_CONFIG_SIZE_FMT = "abbrev";
    protected static URLEncoder urlEncoder;
    protected String configErrMsg = DEFAULT_CONFIG_ERR_MSG;
    protected String configTimeFmt = DEFAULT_CONFIG_TIME_FMT;
    protected String configSizeFmt = DEFAULT_CONFIG_SIZE_FMT;
    protected String className = getClass().getName();
    protected SSIExternalResolver ssiExternalResolver;
    protected long lastModifiedDate;
    protected int debug;
    protected Strftime strftime;
    protected SSIConditionalState conditionalState = new SSIConditionalState();
    static {
        //We try to encode only the same characters that apache does
        urlEncoder = new URLEncoder();
        urlEncoder.addSafeCharacter(',');
        urlEncoder.addSafeCharacter(':');
        urlEncoder.addSafeCharacter('-');
        urlEncoder.addSafeCharacter('_');
        urlEncoder.addSafeCharacter('.');
        urlEncoder.addSafeCharacter('*');
        urlEncoder.addSafeCharacter('/');
        urlEncoder.addSafeCharacter('!');
        urlEncoder.addSafeCharacter('~');
        urlEncoder.addSafeCharacter('\'');
        urlEncoder.addSafeCharacter('(');
        urlEncoder.addSafeCharacter(')');
    }


    public SSIMediator(SSIExternalResolver ssiExternalResolver,
            long lastModifiedDate, int debug) {
        this.ssiExternalResolver = ssiExternalResolver;
        this.lastModifiedDate = lastModifiedDate;
        this.debug = debug;
        setConfigTimeFmt(DEFAULT_CONFIG_TIME_FMT, true);
    }


    public void setConfigErrMsg(String configErrMsg) {
        this.configErrMsg = configErrMsg;
    }


    public void setConfigTimeFmt(String configTimeFmt) {
        setConfigTimeFmt(configTimeFmt, false);
    }


    public void setConfigTimeFmt(String configTimeFmt, boolean fromConstructor) {
        this.configTimeFmt = configTimeFmt;
        //What's the story here with DateTool.LOCALE_US?? Why??
        this.strftime = new Strftime(configTimeFmt, DateTool.LOCALE_US);
        //Variables like DATE_LOCAL, DATE_GMT, and LAST_MODIFIED need to be
        // updated when
        //the timefmt changes. This is what Apache SSI does.
        setDateVariables(fromConstructor);
    }


    public void setConfigSizeFmt(String configSizeFmt) {
        this.configSizeFmt = configSizeFmt;
    }


    public String getConfigErrMsg() {
        return configErrMsg;
    }


    public String getConfigTimeFmt() {
        return configTimeFmt;
    }


    public String getConfigSizeFmt() {
        return configSizeFmt;
    }


    public SSIConditionalState getConditionalState() {
        return conditionalState;
    }


    public Collection getVariableNames() {
        Set variableNames = new HashSet();
        //These built-in variables are supplied by the mediator ( if not
        // over-written by
        // the user ) and always exist
        variableNames.add("DATE_GMT");
        variableNames.add("DATE_LOCAL");
        variableNames.add("LAST_MODIFIED");
        ssiExternalResolver.addVariableNames(variableNames);
        //Remove any variables that are reserved by this class
        Iterator iter = variableNames.iterator();
        while (iter.hasNext()) {
            String name = (String)iter.next();
            if (isNameReserved(name)) {
                iter.remove();
            }
        }
        return variableNames;
    }


    public long getFileSize(String path, boolean virtual) throws IOException {
        return ssiExternalResolver.getFileSize(path, virtual);
    }


    public long getFileLastModified(String path, boolean virtual)
            throws IOException {
        return ssiExternalResolver.getFileLastModified(path, virtual);
    }


    public String getFileText(String path, boolean virtual) throws IOException {
        return ssiExternalResolver.getFileText(path, virtual);
    }


    protected boolean isNameReserved(String name) {
        return name.startsWith(className + ".");
    }


    public String getVariableValue(String variableName) {
        return getVariableValue(variableName, "none");
    }


    public void setVariableValue(String variableName, String variableValue) {
        if (!isNameReserved(variableName)) {
            ssiExternalResolver.setVariableValue(variableName, variableValue);
        }
    }


    public String getVariableValue(String variableName, String encoding) {
        String lowerCaseVariableName = variableName.toLowerCase();
        String variableValue = null;
        if (!isNameReserved(lowerCaseVariableName)) {
            //Try getting it externally first, if it fails, try getting the
            // 'built-in'
            // value
            variableValue = ssiExternalResolver.getVariableValue(variableName);
            if (variableValue == null) {
                variableName = variableName.toUpperCase();
                variableValue = (String)ssiExternalResolver
                        .getVariableValue(className + "." + variableName);
            }
            if (variableValue != null) {
                variableValue = encode(variableValue, encoding);
            }
        }
        return variableValue;
    }


    /**
     * Applies variable substitution to the specified String and returns the
     * new resolved string.
     */
    public String substituteVariables(String val) {
        // If it has no variable references then no work
        // need to be done
        if (val.indexOf('$') < 0) return val;
        StringBuffer sb = new StringBuffer(val);
        for (int i = 0; i < sb.length();) {
            // Find the next $
            for (; i < sb.length(); i++) {
                if (sb.charAt(i) == '$') {
                    i++;
                    break;
                }
            }
            if (i == sb.length()) break;
            // Check to see if the $ is escaped
            if (i > 1 && sb.charAt(i - 2) == '\\') {
                sb.deleteCharAt(i - 2);
                i--;
                continue;
            }
            int nameStart = i;
            int start = i - 1;
            int end = -1;
            int nameEnd = -1;
            char endChar = ' ';
            // Check for {} wrapped var
            if (sb.charAt(i) == '{') {
                nameStart++;
                endChar = '}';
            }
            // Find the end of the var reference
            for (; i < sb.length(); i++) {
                if (sb.charAt(i) == endChar) break;
            }
            end = i;
            nameEnd = end;
            if (endChar == '}') end++;
            // We should now have enough to extract the var name
            String varName = sb.substring(nameStart, nameEnd);
            String value = getVariableValue(varName);
            if (value == null) value = "";
            // Replace the var name with its value
            sb.replace(start, end, value);
            // Start searching for the next $ after the value
            // that was just substituted.
            i = start + value.length();
        }
        return sb.toString();
    }


    protected String formatDate(Date date, TimeZone timeZone) {
        String retVal;
        if (timeZone != null) {
            //we temporarily change strftime. Since SSIMediator is inherently
            // single-threaded, this
            //isn't a problem
            TimeZone oldTimeZone = strftime.getTimeZone();
            strftime.setTimeZone(timeZone);
            retVal = strftime.format(date);
            strftime.setTimeZone(oldTimeZone);
        } else {
            retVal = strftime.format(date);
        }
        return retVal;
    }


    protected String encode(String value, String encoding) {
        String retVal = null;
        if (encoding.equalsIgnoreCase("url")) {
            retVal = urlEncoder.encode(value);
        } else if (encoding.equalsIgnoreCase("none")) {
            retVal = value;
        } else if (encoding.equalsIgnoreCase("entity")) {
            //Not sure how this is really different than none
            retVal = value;
        } else {
            //This shouldn't be possible
            throw new IllegalArgumentException("Unknown encoding: " + encoding);
        }
        return retVal;
    }


    public void log(String message) {
        ssiExternalResolver.log(message, null);
    }


    public void log(String message, Throwable throwable) {
        ssiExternalResolver.log(message, throwable);
    }


    protected void setDateVariables(boolean fromConstructor) {
        boolean alreadySet = ssiExternalResolver.getVariableValue(className
                + ".alreadyset") != null;
        //skip this if we are being called from the constructor, and this has
        // already
        // been set
        if (!(fromConstructor && alreadySet)) {
            ssiExternalResolver.setVariableValue(className + ".alreadyset",
                    "true");
            Date date = new Date();
            TimeZone timeZone = TimeZone.getTimeZone("GMT");
            String retVal = formatDate(date, timeZone);
            //If we are setting on of the date variables, we want to remove
            // them from the
            // user
            //defined list of variables, because this is what Apache does
            setVariableValue("DATE_GMT", null);
            ssiExternalResolver.setVariableValue(className + ".DATE_GMT",
                    retVal);
            retVal = formatDate(date, null);
            setVariableValue("DATE_LOCAL", null);
            ssiExternalResolver.setVariableValue(className + ".DATE_LOCAL",
                    retVal);
            retVal = formatDate(new Date(lastModifiedDate), null);
            setVariableValue("LAST_MODIFIED", null);
            ssiExternalResolver.setVariableValue(className + ".LAST_MODIFIED",
                    retVal);
        }
    }
}