/*******************************************************************************
* Copyright (c) 2000, 2015 IBM Corporation and others.
* All rights reserved. This program and the
* accompanying materials are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors: IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.help.internal.search;
import org.apache.lucene.analysis.*;
import org.eclipse.core.runtime.*;
import org.eclipse.help.internal.base.*;
import org.osgi.framework.*;
/**
* Text Analyzer Descriptor. Encapsulates Lucene Analyzer
*/
public class AnalyzerDescriptor {
private Analyzer luceneAnalyzer;
private String id;
private String lang;
/**
* Constructor
*/
public AnalyzerDescriptor(String locale) {
// try creating the analyzer for the specified locale (usually
// lang_country)
this.luceneAnalyzer = createAnalyzer(locale);
// try creating configured analyzer for the language only
if (this.luceneAnalyzer == null) {
String language = null;
if (locale.length() > 2) {
language = locale.substring(0, 2);
this.luceneAnalyzer = createAnalyzer(language);
}
}
// if all fails, create default analyzer
if (this.luceneAnalyzer == null) {
this.id = HelpBasePlugin.PLUGIN_ID
+ "#" //$NON-NLS-1$
+ HelpBasePlugin.getDefault().getBundle().getHeaders().get(Constants.BUNDLE_VERSION)
+ "?locale=" + locale; //$NON-NLS-1$
this.luceneAnalyzer = new DefaultAnalyzer(locale);
this.lang = locale;
}
}
/**
* Gets the analyzer.
*
* @return Returns a Analyzer
*/
public Analyzer getAnalyzer() {
return new SmartAnalyzer(lang, luceneAnalyzer);
}
/**
* Gets the id.
*
* @return Returns a String
*/
public String getId() {
return id;
}
/**
* Gets the language for the analyzer
*
* @return Returns a String
*/
public String getLang() {
return lang;
}
public String getAnalyzerClassName() {
return luceneAnalyzer.getClass().getName();
}
/**
* Creates analyzer for a locale, if it is configured in the
* org.eclipse.help.luceneAnalyzer extension point. The identifier of the
* analyzer and locale and lang are also set.
*
* @return Analyzer or null if no analyzer is configured for given locale.
*/
private Analyzer createAnalyzer(String locale) {
// find extension point
IConfigurationElement configElements[] = Platform.getExtensionRegistry().getConfigurationElementsFor(
HelpBasePlugin.PLUGIN_ID, "luceneAnalyzer"); //$NON-NLS-1$
for (int i = 0; i < configElements.length; i++) {
if (!configElements[i].getName().equals("analyzer")) //$NON-NLS-1$
continue;
String analyzerLocale = configElements[i].getAttribute("locale"); //$NON-NLS-1$
if (analyzerLocale == null || !analyzerLocale.equals(locale))
continue;
try {
Object analyzer = configElements[i].createExecutableExtension("class"); //$NON-NLS-1$
if (analyzer instanceof AnalyzerFactory)
this.luceneAnalyzer = ((AnalyzerFactory) analyzer).create();
else if (analyzer instanceof Analyzer)
this.luceneAnalyzer = (Analyzer) analyzer;
else
continue;
String pluginId = configElements[i].getContributor().getName();
String pluginVersion = Platform.getBundle(pluginId).getHeaders()
.get(Constants.BUNDLE_VERSION);
this.id = pluginId + "#" + pluginVersion + "?locale=" + locale; //$NON-NLS-1$ //$NON-NLS-2$
this.lang = locale;
if (HelpBasePlugin.PLUGIN_ID.equals(pluginId)) {
// The analyzer is contributed by help plugin.
// Continue in case there is another analyzer for the
// same locale
// let another analyzer take precendence over one from
// help
} else {
// the analyzer does not come from help
return this.luceneAnalyzer;
}
} catch (CoreException ce) {
HelpBasePlugin.logError("Exception occurred creating text analyzer " //$NON-NLS-1$
+ configElements[i].getAttribute("class") //$NON-NLS-1$
+ " for " + locale + " locale.", ce); //$NON-NLS-1$ //$NON-NLS-2$
}
}
return this.luceneAnalyzer;
}
/**
* Checks whether analyzer is compatible with a given analyzer. The ID has
* the form [plugin_id]#[plugin_version]?locale=[locale], for example:
* org.eclipse.help.base#3.1.0?locale=ru
*
* @param analyzerId
* id of analyzer used in the past by the index; id has a form:
* [plugin.id]#[version]?locale=[locale]
* @return true when it is known that given analyzer is compatible with this
* analyzer
*/
public boolean isCompatible(String analyzerId) {
if (analyzerId != null) {
// parse the id
int numberSignIndex = analyzerId.indexOf('#');
int questionMarkIndex = analyzerId.indexOf('?', numberSignIndex);
String pluginId = analyzerId.substring(0, numberSignIndex);
String version = analyzerId.substring(numberSignIndex + 1, questionMarkIndex);
String locale = analyzerId.substring(questionMarkIndex + 1 + "locale=".length()); //$NON-NLS-1$
// plugin compatible?
// must both be org.eclipse.help.base
String thisPluginId = id.substring(0, id.indexOf('#'));
if (!HelpBasePlugin.PLUGIN_ID.equals(pluginId) || !HelpBasePlugin.PLUGIN_ID.equals(thisPluginId)) {
return false;
}
// version compatible?
// must both be >= 3.1
Version vA = getVersion(id);
Version vB = new Version(version);
Version v3_1 = new Version(3, 1, 0);
if (vA.compareTo(v3_1) < 0 && vB.compareTo(v3_1) < 0) {
return false;
}
// locale compatible?
// first part must be equal (first two chars)
if (!lang.substring(0, 2).equals(locale.substring(0, 2))) {
return false;
}
return true;
}
return false;
}
private Version getVersion(String id) {
int idStart = id.indexOf('#');
int idStop = id.indexOf('?');
String value = idStop == -1 ? id.substring(idStart + 1) : id.substring(idStart + 1, idStop);
return new Version(value);
}
}
