jlive 索引解析

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我是靠谱客的博主文艺夕阳，最近开发中收集的这篇文章主要介绍jlive 索引解析，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

/**
* Copyright (C) 2001 Yasna.com. All rights reserved.
*
* ===================================================================
* The Apache Software License, Version 1.1
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by
* Yasna.com (http://www.yasna.com)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Yazd" and "Yasna.com" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please
* contact yazd@yasna.com.
*
* 5. Products derived from this software may not be called "Yazd",
* nor may "Yazd" appear in their name, without prior written
* permission of Yasna.com.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL YASNA.COM OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of Yasna.com. For more information
* on Yasna.com, please see <http://www.yasna.com>.
*/

/**
* Copyright (C) 2000 CoolServlets.com. All rights reserved.
*
* ===================================================================
* The Apache Software License, Version 1.1
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by
* CoolServlets.com (http://www.coolservlets.com)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Jive" and "CoolServlets.com" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please
* contact webmaster@coolservlets.com.
*
* 5. Products derived from this software may not be called "Jive",
* nor may "Jive" appear in their name, without prior written
* permission of CoolServlets.com.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL COOLSERVLETS.COM OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of CoolServlets.com. For more information
* on CoolServlets.com, please see <http://www.coolservlets.com>.
*/

package com.Yasna.forum.database;

import java.util.Date;
import java.util.Iterator;
import java.io.IOException;
import java.io.File;

import com.lucene.analysis.*;
import com.lucene.analysis.standard.*;
import com.lucene.document.*;
import com.lucene.store.*;
import com.lucene.search.*;
import com.lucene.queryParser.*;
import com.lucene.index.*;

import com.Yasna.forum.*;

/**
* Database implementation of the Query interface using Lucene.
*/
public class DbQuery implements com.Yasna.forum.Query {

/**
* The query String to use for searching. Set it the empty String by
* default so that if the user fails to set a query String, there won't
* be errors.
*/
private String queryString = "";
private java.util.Date beforeDate = null;
private java.util.Date afterDate = null;
private User user = null;
private ForumThread thread = null;

/**
* The results of the query as an array of message ID's.
*/
private int [] results = null;

private Forum forum;
private DbForumFactory factory;

/**
* The maximum number of results to return with a search.
*/
private static final int MAX_RESULTS_SIZE = 500;

private static String indexPath = null;
private static IndexReader reader;
private static Searcher searcher;
private static Directory searchDirectory = null;
private static long indexLastModified;
private static Analyzer analyzer = new StandardAnalyzer();

public DbQuery(Forum forum, DbForumFactory factory){
this.forum = forum;
this.factory = factory;
}

public void setQueryString(String queryString) {
this.queryString = queryString;
//reset results
results = null;
}

public String getQueryString() {
return queryString;
}

public void setBeforeDate(java.util.Date beforeDate) {
this.beforeDate = beforeDate;
//reset results
results = null;
}

public java.util.Date getBeforeDate() {
return beforeDate;
}

public void setAfterDate(java.util.Date afterDate){
this.afterDate = afterDate;
//reset results
results = null;
}

public java.util.Date getAfterDate(){
return afterDate;
}

public User getFilteredUser() {
return user;
}

public void filterOnUser(User user) {
this.user = user;
results = null;
}

public ForumThread getFilteredThread() {
return thread;
}

public void filterOnThread(ForumThread thread) {
this.thread = thread;
results = null;
}

public int resultCount() {
if (results == null) {
executeQuery();
}
return results.length;
}

public Iterator results() {
if (results == null) {
executeQuery();
}
return new DbQueryIterator(results, factory);
}

public Iterator results(int startIndex, int numResults){
if (results == null) {
executeQuery();
}
return new DbQueryIterator(results, factory, startIndex, numResults);
}

/**
* Execute the query and store the results in the results array.
*/
private void executeQuery() {
try {
Searcher searcher = getSearcher();
if (searcher == null) {
//Searcher can be null if the index doesn't exist.
results = new int[0];
return;
}

com.lucene.search.Query bodyQuery =
QueryParser.parse(queryString, "body", analyzer);

com.lucene.search.Query subjectQuery =
QueryParser.parse(queryString, "subject", analyzer);

String forumID = Integer.toString(forum.getID());

BooleanQuery comboQuery = new BooleanQuery();
comboQuery.add(subjectQuery,false,false);
comboQuery.add(bodyQuery,false,false);

MultiFilter multiFilter = new MultiFilter(3);

//Forum filter
multiFilter.add(new FieldFilter("forumID", forumID));

//Date filter
if (beforeDate != null || afterDate != null) {
if (beforeDate != null && afterDate != null) {
multiFilter.add(new DateFilter("creationDate", beforeDate, afterDate));
}
else if (beforeDate == null) {
multiFilter.add(DateFilter.After("creationDate", afterDate));
}
else {
multiFilter.add(DateFilter.Before("creationDate", beforeDate));
}
}

//User filter
if (user != null) {
String userID = Integer.toString(user.getID());
multiFilter.add(new FieldFilter("userID", userID));
}

//Thread filter
if (thread != null) {
String threadID = Integer.toString(thread.getID());
multiFilter.add(new FieldFilter("threadID", threadID));
}

Hits hits = searcher.search(comboQuery, multiFilter);
//Don't return more search results than the maximum number allowed.
int numResults = hits.length() < MAX_RESULTS_SIZE ?
hits.length() : MAX_RESULTS_SIZE;
int [] messages = new int[numResults];
for (int i=0; i<numResults; i++) {
messages[i] = Integer.parseInt( ((Document)hits.doc(i)).get("messageID") );
}
results = messages;
}
catch (Exception e) {
e.printStackTrace();
results = new int[0];
}
}

/**
* Returns a Lucene Searcher that can be used to execute queries. Lucene
* can handle index reading even while updates occur. However, in order
* for index changes to be reflected in search results, the reader must
* be re-opened whenever the modifiedDate changes.<p>
*
* The location of the index is the "search" subdirectory in [yazdHome]. If
* yazdHome is not set correctly, this method will fail.
*
* @return a Searcher that can be used to execute queries.
*/
private static Searcher getSearcher() throws IOException {
if (indexPath == null) {
//Get path of where search index should be. It should be
//the search subdirectory of [yazdHome].
String yazdHome = PropertyManager.getProperty("yazdHome");
if (yazdHome == null) {
System.err.println("ERROR: the yazdHome property is not set.");
throw new IOException("Unable to open index for searching " +
"because yazdHome was not set.");
}
indexPath = yazdHome + File.separator + "search";
}

if (searcher == null) {
//Acquire a lock -- analyzer is a convenient object to do this on.
synchronized(analyzer) {
if (searcher == null) {
if (indexExists(indexPath)) {
searchDirectory = new FSDirectory(indexPath, false);
reader = IndexReader.open(searchDirectory);
indexLastModified = reader.lastModified(searchDirectory);
searcher = new IndexSearcher(reader);
}
//Otherwise, the index doesn't exist, so return null.
else {
return null;
}
}
}
}
if (reader.lastModified(searchDirectory) > indexLastModified) {
synchronized (analyzer) {
if (reader.lastModified(searchDirectory) > indexLastModified) {
if (indexExists(indexPath)) {
indexLastModified = reader.lastModified(searchDirectory);
//We need to close the indexReader because it has changed.
//Re-opening it will make changes visible.
reader.close();

searchDirectory = new FSDirectory(indexPath, false);
reader = IndexReader.open(searchDirectory);
searcher = new IndexSearcher(reader);
}
//Otherwise, the index doesn't exist, so return null.
else {
return null;
}
}
}
}
return searcher;
}

/**
* Returns true if the search index exists at the specified path.
*
* @param indexPath the path to check for the search index at.
*/
private static boolean indexExists(String indexPath) {
//Lucene always creates a file called "segments" -- if it exists, we
//assume that the search index exists.
File segments = new File(indexPath + File.separator + "segments");
return segments.exists();
}
}