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* 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.james.util;
import org.apache.oro.text.perl.MalformedPerl5PatternException;
import org.apache.oro.text.perl.Perl5Util;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.NodeList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/*
* This is derived from the SQLResources.java class that we have been
* using to provide SQL strings based upon the particular drive being
* used.
*
* The format is indentical to the format used by SQLResources. The
* only difference are the names of the elements and attributes. A
* mapping is as follows:
*
* sqlResources xmlResources
* ------------ ------------
* sqlResources resources
* dbMatchers matchers
* dbMatcher matcher
* db for
* databaseProductName match
* sqlDefs group
* sql resource
*
* This class provides String resources defined in XML. Resources are
* organized into groups, and identified by name. For each resource
* there can be a standard value, and custom values matched by regular
* expression.
*
* The structure of the XML file is:
*
* <resources>
* <matchers>
* <matcher for="<i>label</i>" match="<i>regular expression</i>"/>
* ...
* </matchers>
* <group name="<i>group name</i>">
* <resource name="<i>resouce name</i>" [for="<i>match label</i>"]><i>text, including ${placeholders}, which will be replaced at runtime.</i></resource>
* ...
* </group>
* <i>... more <group> elements ...</i>
* </resources>
*
*/
public class XMLResources
{
/**
* A map of statement types to resource strings
*/
private Map m_resource = new HashMap();
/**
* A set of all used String values
*/
static private Map stringTable = java.util.Collections.synchronizedMap(new HashMap());
/**
* A Perl5 regexp matching helper class
*/
private Perl5Util m_perl5Util = new Perl5Util();
/**
* Configures an XMLResources object to provide string statements from a file.
*
* Parameters encoded as $(parameter} in the input file are
* replace by values from the parameters Map, if the named parameter exists.
* Parameter values may also be specified in the resourceSection element.
*
* @param xmlFile the input file containing the string definitions
* @param group xml element containing the strings to be used
* @param select if customized elements exist for this value, use them instead of the default
* @param configParameters a map of parameters (name-value string pairs) which are
* replaced where found in the input strings
*/
public void init(File xmlFile, String group,
String select, Map configParameters)
throws Exception
{
// Parse the xmlFile as an XML document.
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(xmlFile);
// First process the matchers, to select the statements to use.
Element matcherElement =
(Element)(doc.getElementsByTagName("matchers").item(0));
String selectTag = null;
if ( matcherElement != null ) {
selectTag = match(select, matcherElement);
m_perl5Util = null; // release the PERL matcher!
}
// Now get the section defining strings for the group required.
NodeList sections = doc.getElementsByTagName("group");
int sectionsCount = sections.getLength();
Element sectionElement = null;
for (int i = 0; i < sectionsCount; i++ ) {
sectionElement = (Element)(sections.item(i));
String sectionName = sectionElement.getAttribute("name");
if ( sectionName != null && sectionName.equals(group) ) {
break;
}
}
if ( sectionElement == null ) {
StringBuffer exceptionBuffer =
new StringBuffer(64)
.append("Error loading string definition file. ")
.append("The element named \'")
.append(group)
.append("\' does not exist.");
throw new RuntimeException(exceptionBuffer.toString());
}
// Get parameters defined within the file as defaults,
// and use supplied parameters as overrides.
Map parameters = new HashMap();
// First read from the <params> element, if it exists.
Element parametersElement =
(Element)(sectionElement.getElementsByTagName("parameters").item(0));
if ( parametersElement != null ) {
NamedNodeMap params = parametersElement.getAttributes();
int paramCount = params.getLength();
for (int i = 0; i < paramCount; i++ ) {
Attr param = (Attr)params.item(i);
String paramName = param.getName();
String paramValue = param.getValue();
parameters.put(paramName, paramValue);
}
}
// Then copy in the parameters supplied with the call.
parameters.putAll(configParameters);
// 2 maps - one for storing default statements,
// the other for statements with a "for" attribute matching this
// connection.
Map defaultStrings = new HashMap();
Map selectTagStrings = new HashMap();
// Process each string resource, replacing string parameters,
// and adding to the appropriate map..
NodeList resDefs = sectionElement.getElementsByTagName("resource");
int resCount = resDefs.getLength();
for ( int i = 0; i < resCount; i++ ) {
// See if this needs to be processed (is default or product specific)
Element resElement = (Element)(resDefs.item(i));
String resSelect = resElement.getAttribute("for");
Map resMap;
if ( resSelect.equals("")) {
// default
resMap = defaultStrings;
}
else if (resSelect.equals(selectTag) ) {
// Specific to this product
resMap = selectTagStrings;
}
else {
// for a different product
continue;
}
// Get the key and value for this string resource.
String resKey = resElement.getAttribute("name");
if ( resKey == null ) {
// ignore elements without a "name" attribute.
continue;
}
String resString = resElement.getFirstChild().getNodeValue();
// Do parameter replacements for this string resource.
Iterator paramNames = parameters.keySet().iterator();
while ( paramNames.hasNext() ) {
String paramName = (String)paramNames.next();
String paramValue = (String)parameters.get(paramName);
StringBuffer replaceBuffer =
new StringBuffer(64)
.append("${")
.append(paramName)
.append("}");
resString = substituteSubString(resString, replaceBuffer.toString(), paramValue);
}
// See if we already have registered a string of this value
String shared = (String) stringTable.get(resString);
// If not, register it -- we will use it next time
if (shared == null) {
stringTable.put(resString, resString);
} else {
resString = shared;
}
// Add to the resMap - either the "default" or the "product" map
resMap.put(resKey, resString);
}
// Copy in default strings, then overwrite product-specific ones.
m_resource.putAll(defaultStrings);
m_resource.putAll(selectTagStrings);
}
/**
* Compares the "select" value against a set of regular expressions
* defined in XML. The first successful match defines the name of a
* selector tag. This value is then used to choose the specific
* expressions to use.
*
* @param select the String to be checked
* @param matchersElement the XML element containing selector patterns
*
* @return the selector tag that will be used to select custom resources
*
*/
private String match(String select, Element matchersElement)
throws MalformedPerl5PatternException
{
String selectTagName = select;
NodeList matchers = matchersElement.getElementsByTagName("matcher");
for ( int i = 0; i < matchers.getLength(); i++ ) {
// Get the values for this matcher element.
Element matcher = (Element)matchers.item(i);
String matchName = matcher.getAttribute("for");
StringBuffer selectTagPatternBuffer =
new StringBuffer(64)
.append("/")
.append(matcher.getAttribute("match"))
.append("/i");
// If the select string matches the pattern, use the match
// name from this matcher.
if ( m_perl5Util.match(selectTagPatternBuffer.toString(), selectTagName) ) {
return matchName;
}
}
return null;
}
/**
* Replace substrings of one string with another string and return altered string.
* @param input input string
* @param find the string to replace
* @param replace the string to replace with
* @return the substituted string
*/
static private String substituteSubString( String input,
String find,
String replace )
{
int find_length = find.length();
int replace_length = replace.length();
StringBuffer output = new StringBuffer(input);
int index = input.indexOf(find);
int outputOffset = 0;
while ( index > -1 ) {
output.replace(index + outputOffset, index + outputOffset + find_length, replace);
outputOffset = outputOffset + (replace_length - find_length);
index = input.indexOf(find, index + find_length);
}
String result = output.toString();
return result;
}
/**
* Returns a named string for the specified key.
*
* @param name the name of the String resource required.
* @return the requested resource
*/
public String getString(String name)
{
return (String)m_resource.get(name);
}
/**
* Returns a named string for the specified key.
*
* @param name the name of the String resource required.
* @param required true if the resource is required
* @return the requested resource
* @throws ConfigurationException
* if a required resource cannot be found.
*/
public String getString(String name, boolean required)
{
String str = getString(name);
if (str == null && required) {
StringBuffer exceptionBuffer =
new StringBuffer(64)
.append("Required String resource: '")
.append(name)
.append("' was not found.");
throw new IllegalArgumentException(exceptionBuffer.toString());
}
return str;
}
/**
* Returns a named string, replacing parameters with the values set in a Map.
*
* @param name the name of the String resource required.
* @param parameters a map of parameters (name-value string pairs) which are
* replaced where found in the input strings
* @return the requested resource
*/
public String getString(String name, Map parameters)
{
return replaceParameters(getString(name), parameters);
}
/**
* Returns a named string, replacing parameters with the values set in a Map.
*
* @param name the name of the String resource required.
* @param parameters a map of parameters (name-value string pairs) which are
* replaced where found in the input strings
* @return the requested resource
*/
public String getString(String name, Map parameters, boolean required)
{
return replaceParameters(getString(name, required), parameters);
}
/**
* Returns a named string, replacing parameters with the values set.
*
* @param name the name of the String resource required.
* @param parameters a map of parameters (name-value string pairs) which are
* replaced where found in the input strings
* @return the requested resource
*/
static public String replaceParameters(String str, Map parameters)
{
if (str != null && parameters != null) {
// Do parameter replacements for this string resource.
Iterator paramNames = parameters.keySet().iterator();
StringBuffer replaceBuffer = new StringBuffer(64);
while ( paramNames.hasNext() ) {
String paramName = (String)paramNames.next();
String paramValue = (String)parameters.get(paramName);
replaceBuffer.append("${").append(paramName).append("}");
str = substituteSubString(str, replaceBuffer.toString(), paramValue);
if (paramNames.hasNext()) replaceBuffer.setLength(0);
}
}
return str;
}
}
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