Java tutorial
/* * The contents of this file are subject to the Mozilla Public License Version 1.1 * (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.mozilla.org/MPL/>. * * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT * WARRANTY OF ANY KIND, either express or implied. See the License for the specific * language governing rights and limitations under the License. * * The Original Code is the Venice Web Communities System. * * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>, * for Silverwrist Design Studios. Portions created by Eric J. Bowersox are * Copyright (C) 2003 Eric J. Bowersox/Silverwrist Design Studios. All Rights Reserved. * * Contributor(s): */ package com.silverwrist.dynamo.index; import java.io.*; import java.lang.ref.*; import java.util.*; import org.apache.log4j.Logger; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.document.*; import org.apache.lucene.index.*; import org.apache.lucene.search.*; import org.apache.lucene.store.Directory; import com.silverwrist.util.*; import com.silverwrist.dynamo.except.*; import com.silverwrist.dynamo.iface.*; import com.silverwrist.dynamo.util.*; class IndexServiceImpl implements IndexService { /*-------------------------------------------------------------------------------- * Internal counting HitCollector *-------------------------------------------------------------------------------- */ private static class CountingCollector extends HitCollector { /*==================================================================== * Attributes *==================================================================== */ private int m_count = 0; /*==================================================================== * Constructor *==================================================================== */ CountingCollector() { // do nothing } // end constructor /*==================================================================== * Abstract implementations from class HitCollector *==================================================================== */ public void collect(int doc, float score) { m_count++; } // end collect /*==================================================================== * External operations *==================================================================== */ int getCount() { return m_count; } // end getCount } // end class CountingCollector /*-------------------------------------------------------------------------------- * Internal HitCollector that gathers a request subset *-------------------------------------------------------------------------------- */ private class SubsetCollector extends HitCollector { /*==================================================================== * Attributes *==================================================================== */ private int[] m_docs; private float[] m_scores; private int m_offset; private int m_size = 0; /*==================================================================== * Constructor *==================================================================== */ SubsetCollector(int offset, int count) { m_docs = new int[count]; m_scores = new float[count]; m_offset = offset; } // end constructor /*==================================================================== * Abstract implementations from class HitCollector *==================================================================== */ public void collect(int doc, float score) { if (m_offset > 0) { // skip documents at beginning of list m_offset--; return; } // end if if (m_size < m_docs.length) { // add document index and score to the list m_docs[m_size] = doc; m_scores[m_size++] = score; } // end if } // end collect /*==================================================================== * External operations *==================================================================== */ public List outputItems(IndexReader irdr) throws IOException, IndexException { if (m_size == 0) return Collections.EMPTY_LIST; ArrayList rc = new ArrayList(m_size); for (int i = 0; i < m_size; i++) { // get the document and retrieve its "id" field, then use that to get the object Document doc = irdr.document(m_docs[i]); Field id_field = doc.getField("id"); String fulltag = id_field.stringValue(); if (fulltag == null) fulltag = IOUtils.load(id_field.readerValue()).toString(); String[] elts = StringUtils.split1(fulltag, '|', 3); Object value = m_base.resolveObjectReference(elts[0], elts[1], elts[2]); rc.add(new ItemAndScore(value, m_scores[i])); } // end for return Collections.unmodifiableList(rc); } // end outputItems } // end class SubsetCollector /*-------------------------------------------------------------------------------- * Static data members *-------------------------------------------------------------------------------- */ private static Logger logger = Logger.getLogger(IndexServiceImpl.class); /*-------------------------------------------------------------------------------- * Attributes *-------------------------------------------------------------------------------- */ private QualifiedNameKey m_identity; private IndexManagerObject m_base; private Analyzer m_analyzer; private IndexDirectoryImpl m_directory; private DirectoryAutoCleanup m_cleanup; /*-------------------------------------------------------------------------------- * Constructor *-------------------------------------------------------------------------------- */ IndexServiceImpl(IndexManagerObject base, QualifiedNameKey identity, int ndx, IndexOps ops, ReferenceQueue rq, boolean create) throws DatabaseException, IndexException { m_analyzer = createAnalyzer(ops.getAnalyzerClassName(ndx)); m_base = base; m_identity = identity; m_directory = new IndexDirectoryImpl(ndx, ops); m_cleanup = new DirectoryAutoCleanup(this, m_directory, rq); if (create) { // create the new index try { // Use an IndexWriter to create the index for the first time. IndexWriter iwr = new IndexWriter(m_directory, m_analyzer, true); iwr.close(); } // end try catch (IOException e) { // translate Lucene's IOException here IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "indexCreate.fail", e); ie.setParameter(0, m_identity.toString()); throw ie; } // end catch } // end if } // end constructor /*-------------------------------------------------------------------------------- * Internal operations *-------------------------------------------------------------------------------- */ private static final void visitAllDocuments(IndexSearcher srch, HitCollector c) throws IOException { for (int i = 0; i < srch.maxDoc(); i++) c.collect(i, 1.0F); } // end visitAllDocuments private final String createTag(String namespace, String name, Object obj) throws IndexException { String objtag = m_base.getResolver(namespace, name).getResolverTag(obj); return namespace + "|" + name + "|" + objtag; } // end createTag private final Query compileInternal(String query_string, java.util.Date date_low, java.util.Date date_high, DynamoUser match_owner, String match_scope) throws IndexException { ArrayList queries = new ArrayList(); if (query_string != null) { // we have a query language string... try { // parse the query string, which matches on the "text" field only queries.add(Parser.parse(query_string)); } // end try catch (ParseException pe) { // parse error in the query IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "query.syntax", pe); ie.setParameter(0, pe.getMessage()); throw ie; } // end catch } // end if if ((date_low != null) || (date_high != null)) { // add an inclusive range of dates Term term_low = null, term_high = null; if (date_low != null) term_low = new Term("date", DateField.dateToString(date_low)); if (date_high != null) term_high = new Term("date", DateField.dateToString(date_high)); queries.add(new RangeQuery(term_low, term_high, true)); } // end if if (match_owner != null) queries.add(new TermQuery(new Term("owner", match_owner.getName()))); if (match_scope != null) { // treat "scope" as a possible wildcard match and create it if (match_scope.indexOf('?') >= 0) queries.add(new WildcardQuery(new Term("scope", match_scope))); else if (match_scope.indexOf('*') >= 0) { // append another query String s = match_scope.substring(0, match_scope.length() - 1); if (s.indexOf('*') < 0) queries.add(new PrefixQuery(new Term("scope", s))); else queries.add(new WildcardQuery(new Term("scope", match_scope))); } // end else if else // match the scope directly queries.add(new TermQuery(new Term("scope", match_scope))); } // end if // Boil down all the queries for me. if (queries.size() == 0) return null; if (queries.size() == 1) return (Query) (queries.get(0)); BooleanQuery rc = new BooleanQuery(); for (int i = 0; i < queries.size(); i++) rc.add((Query) (queries.get(i)), true, false); return rc; } // end compileInternal private final List doQuery(Query query, int offset, int count) throws IndexException { SubsetCollector subc = new SubsetCollector(offset, count + 1); List rc = null; IndexReader irdr = null; IndexSearcher srch = null; try { // run that puppy! irdr = IndexReader.open(m_directory); srch = new IndexSearcher(irdr); if (query == null) visitAllDocuments(srch, subc); else srch.search(query, subc); rc = subc.outputItems(irdr); } // end try catch (IOException e) { // the query failed somehow - throw an error throw new IndexException(IndexServiceImpl.class, "IndexMessages", "query.fail", e); } // end catch finally { // make sure we close down OK try { // close the search and index reader if (srch != null) srch.close(); if (irdr != null) irdr.close(); } // end try catch (IOException e) { // shouldn't happen logger.warn("query(): error closing stuff", e); } // end catch } // end finally return rc; } // end doQuery private final int doQueryCount(Query query) throws IndexException { CountingCollector cc = new CountingCollector(); IndexSearcher srch = null; try { // run that puppy! srch = new IndexSearcher(m_directory); if (query == null) visitAllDocuments(srch, cc); else srch.search(query, cc); } // end try catch (IOException e) { // the query failed somehow - throw an error throw new IndexException(IndexServiceImpl.class, "IndexMessages", "query.fail", e); } // end catch finally { // make sure we close down OK try { // close the search and index reader if (srch != null) srch.close(); } // end try catch (IOException e) { // shouldn't happen logger.warn("queryCount(): error closing stuff", e); } // end catch } // end finally return cc.getCount(); } // end doQueryCount /*-------------------------------------------------------------------------------- * Implementations from interface IndexService *-------------------------------------------------------------------------------- */ public void addItem(String item_namespace, String item_name, Object item, String scope, java.util.Date date, DynamoUser owner, String text) throws IndexException { // Create a new Lucene Document containing the item information. Document doc = new Document(); doc.add(Field.Keyword("id", createTag(item_namespace, item_name, item))); doc.add(Field.Keyword("date", date)); doc.add(Field.Keyword("owner", owner.getName())); doc.add(Field.Keyword("scope", scope)); doc.add(Field.UnStored("text", text)); try { // Use an IndexWriter to write it to the index. IndexWriter iwr = new IndexWriter(m_directory, m_analyzer, false); iwr.addDocument(doc); iwr.close(); } // end try catch (IOException e) { // translate Lucene's IOException here IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "addItem.fail", e); ie.setParameter(0, item_namespace); ie.setParameter(1, item_name); ie.setParameter(2, m_identity.toString()); throw ie; } // end catch } // end addItem public boolean deleteItem(String item_namespace, String item_name, Object item) throws IndexException { // Create a Lucene Term matching the given document. Term term = new Term("id", createTag(item_namespace, item_name, item)); try { // Use an IndexReader to delete the appropriate document. IndexReader irdr = IndexReader.open(m_directory); int ndel = irdr.delete(term); irdr.close(); return (ndel > 0); } // end try catch (IOException e) { // translate Lucene's IOException here IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "deleteItem.fail", e); ie.setParameter(0, item_namespace); ie.setParameter(1, item_name); ie.setParameter(2, m_identity.toString()); throw ie; } // end catch } // end deleteItem public CompiledQuery compileQuery(String query_string, java.util.Date date_low, java.util.Date date_high, DynamoUser match_owner, String match_scope) throws IndexException { Query query = compileInternal(query_string, date_low, date_high, match_owner, match_scope); return new CompiledQuery(query); } // end compileQuery public List query(String query_string, java.util.Date date_low, java.util.Date date_high, DynamoUser match_owner, String match_scope, int offset, int count) throws IndexException { Query query = compileInternal(query_string, date_low, date_high, match_owner, match_scope); return doQuery(query, offset, count); } // end query public List query(CompiledQuery query, int offset, int count) throws IndexException { return doQuery(query.getQuery(), offset, count); } // end query public int queryCount(String query_string, java.util.Date date_low, java.util.Date date_high, DynamoUser match_owner, String match_scope) throws IndexException { Query query = compileInternal(query_string, date_low, date_high, match_owner, match_scope); return doQueryCount(query); } // end queryCount public int queryCount(CompiledQuery query) throws IndexException { return doQueryCount(query.getQuery()); } // end queryCount /*-------------------------------------------------------------------------------- * External operations *-------------------------------------------------------------------------------- */ void abandon() { m_cleanup.clear(); m_directory.abandon(); } // end abandon /*-------------------------------------------------------------------------------- * External static operations *-------------------------------------------------------------------------------- */ static Analyzer createAnalyzer(String classname) throws IndexException { try { // Create the analyzer class. return (Analyzer) (Class.forName(classname).newInstance()); } // end try catch (ClassNotFoundException e) { // unable to find the Analyzer class IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "analyzer.class.notfound", e); ie.setParameter(0, classname); throw ie; } // end catch catch (IllegalAccessException e) { // problem creating the analyzer class IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "analyzer.noCreate", e); ie.setParameter(0, classname); throw ie; } // end catch catch (InstantiationException e) { // unable to instantiate the class IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "analyzer.noCreate", e); ie.setParameter(0, classname); throw ie; } // end catch catch (ClassCastException e) { // bad class specified IndexException ie = new IndexException(IndexServiceImpl.class, "IndexMessages", "analyzer.badType", e); ie.setParameter(0, classname); throw ie; } // end catch } // end createAnalyzer } // end class IndexServiceImpl