Java tutorial
/** * 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.solr.handler; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.index.Term; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.spell.Dictionary; import org.apache.lucene.search.spell.SpellChecker; import org.apache.lucene.search.spell.HighFrequencyDictionary; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.store.RAMDirectory; import org.apache.solr.request.SolrQueryRequest; import org.apache.solr.response.SolrQueryResponse; import org.apache.solr.common.SolrException; import org.apache.solr.common.params.SolrParams; import org.apache.solr.common.util.NamedList; import org.apache.solr.common.util.SimpleOrderedMap; import org.apache.solr.core.SolrCore; import org.apache.solr.util.plugin.SolrCoreAware; import java.io.File; import java.io.IOException; import java.net.URL; import java.util.Arrays; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Takes a string (e.g. a query string) as the value of the "q" parameter * and looks up alternative spelling suggestions in the spellchecker. * The spellchecker used by this handler is the Lucene contrib SpellChecker. * <style> pre.code { border: 1pt solid #AEBDCC; background-color: #F3F5F7; padding: 5pt; font-family: courier, monospace; white-space: pre; // begin css 3 or browser specific rules - do not remove! //see: http://forums.techguy.org/archive/index.php/t-249849.html white-space: pre-wrap; word-wrap: break-word; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; // end css 3 or browser specific rules } </style> * * <p>The results identifies the original words echoing it as an entry with the * name of "words" and original word value. It * also identifies if the requested "words" is contained in the index through * the use of the exist true/false name value. Examples of these output * parameters in the standard output format is as follows:</p> * <pre class="code"> <str name="words">facial</str> <str name="exist">true</str> </pre> * * <p>If a query string parameter of "extendedResults" is used, then each word within the * "q" parameter (seperated by a space or +) will * be iterated through the spell checker and will be wrapped in an * NamedList. Each word will then get its own set of results: words, exists, and * suggestions.</p> * <P><bold>NOTE</bold>: Query terms are simply split on whitespace when using extendedResults mode. This is may not be adequate. * See the {@link org.apache.solr.handler.component.SpellCheckComponent} for alternatives. * </P> * <p>Also note that multiword queries will be treated as a single term if extendedResults is false. This may or may not make sense * depending on how the spelling field was indexed.</p> * * <p>Examples of the use of the standard ouput (XML) without and with the * use of the "extendedResults" parameter are as follows.</p> * * <p> The following URL * examples were configured with the solr.SpellCheckerRequestHandler * named as "/spellchecker".</p> * * <p>Without the use of "extendedResults" and one word * spelled correctly: facial </p> * <pre class="code">http://.../spellchecker?indent=on&onlyMorePopular=true&accuracy=.6&suggestionCount=20&q=facial</pre> * <pre class="code"> <?xml version="1.0" encoding="UTF-8"?> <response> <lst name="responseHeader"> <int name="status">0</int> <int name="QTime">6</int> </lst> <str name="words">facial</str> <str name="exist">true</str> <arr name="suggestions"> <str>faciale</str> <str>faucial</str> <str>fascial</str> <str>facing</str> <str>faciei</str> <str>facialis</str> <str>social</str> <str>facile</str> <str>spacial</str> <str>glacial</str> <str>marcial</str> <str>facies</str> <str>facio</str> </arr> </response> </pre> * * <p>Without the use of "extendedResults" and two words, * one spelled correctly and one misspelled: facial salophosphoprotein </p> * <pre class="code">http://.../spellchecker?indent=on&onlyMorePopular=true&accuracy=.6&suggestionCount=20&q=facial+salophosphoprotein</pre> * <pre class="code"> <?xml version="1.0" encoding="UTF-8"?> <response> <lst name="responseHeader"> <int name="status">0</int> <int name="QTime">18</int> </lst> <str name="words">facial salophosphoprotein</str> <str name="exist">false</str> <arr name="suggestions"> <str>sialophosphoprotein</str> </arr> </response> </pre> * * * <p>With the use of "extendedResults" and two words, * one spelled correctly and one misspelled: facial salophosphoprotein </p> * <pre class="code">http://.../spellchecker?indent=on&onlyMorePopular=true&accuracy=.6&suggestionCount=20&extendedResults=true&q=facial+salophosphoprotein</pre> * <pre class="code"> <?xml version="1.0" encoding="UTF-8"?> <response> <lst name="responseHeader"> <int name="status">0</int> <int name="QTime">23</int> </lst> <lst name="result"> <lst name="facial"> <int name="frequency">1</int> <lst name="suggestions"> <lst name="faciale"><int name="frequency">1</int></lst> <lst name="faucial"><int name="frequency">1</int></lst> <lst name="fascial"><int name="frequency">1</int></lst> <lst name="facing"><int name="frequency">1</int></lst> <lst name="faciei"><int name="frequency">1</int></lst> <lst name="facialis"><int name="frequency">1</int></lst> <lst name="social"><int name="frequency">1</int></lst> <lst name="facile"><int name="frequency">1</int></lst> <lst name="spacial"><int name="frequency">1</int></lst> <lst name="glacial"><int name="frequency">1</int></lst> <lst name="marcial"><int name="frequency">1</int></lst> <lst name="facies"><int name="frequency">1</int></lst> <lst name="facio"><int name="frequency">1</int></lst> </lst> </lst> <lst name="salophosphoprotein"> <int name="frequency">0</int> <lst name="suggestions"> <lst name="sialophosphoprotein"><int name="frequency">1</int></lst> <lst name="phosphoprotein"><int name="frequency">1</int></lst> <lst name="phosphoproteins"><int name="frequency">1</int></lst> <lst name="alphalipoprotein"><int name="frequency">1</int></lst> </lst> </lst> </lst> </response> </pre> * * @see <a href="http://wiki.apache.org/jakarta-lucene/SpellChecker">The Lucene Spellchecker documentation</a> * * * @deprecated Use {@link org.apache.solr.handler.component.SpellCheckComponent} instead. * * See also https://issues.apache.org/jira/browse/SOLR-474 and https://issues.apache.org/jira/browse/SOLR-485 * */ @Deprecated public class SpellCheckerRequestHandler extends RequestHandlerBase implements SolrCoreAware { private static Logger log = LoggerFactory.getLogger(SpellCheckerRequestHandler.class); private SpellChecker spellChecker; /* * From http://wiki.apache.org/jakarta-lucene/SpellChecker * If reader and restrictToField are both not null: * 1. The returned words are restricted only to the words presents in the field * "restrictToField "of the Lucene Index "reader". * * 2. The list is also sorted with a second criterium: the popularity (the * frequence) of the word in the user field. * * 3. If "onlyMorePopular" is true and the mispelled word exist in the user field, * return only the words more frequent than this. * */ protected Directory spellcheckerIndexDir = new RAMDirectory(); protected String dirDescription = "(ramdir)"; protected String termSourceField; protected static final String PREFIX = "sp."; protected static final String QUERY_PREFIX = PREFIX + "query."; protected static final String DICTIONARY_PREFIX = PREFIX + "dictionary."; protected static final String SOURCE_FIELD = DICTIONARY_PREFIX + "termSourceField"; protected static final String INDEX_DIR = DICTIONARY_PREFIX + "indexDir"; protected static final String THRESHOLD = DICTIONARY_PREFIX + "threshold"; protected static final String ACCURACY = QUERY_PREFIX + "accuracy"; protected static final String SUGGESTIONS = QUERY_PREFIX + "suggestionCount"; protected static final String POPULAR = QUERY_PREFIX + "onlyMorePopular"; protected static final String EXTENDED = QUERY_PREFIX + "extendedResults"; protected static final float DEFAULT_ACCURACY = 0.5f; protected static final int DEFAULT_SUGGESTION_COUNT = 1; protected static final boolean DEFAULT_MORE_POPULAR = false; protected static final boolean DEFAULT_EXTENDED_RESULTS = false; protected static final float DEFAULT_DICTIONARY_THRESHOLD = 0.0f; protected SolrParams args = null; @Override public void init(NamedList args) { super.init(args); this.args = SolrParams.toSolrParams(args); } public void inform(SolrCore core) { termSourceField = args.get(SOURCE_FIELD, args.get("termSourceField")); try { String dir = args.get(INDEX_DIR, args.get("spellcheckerIndexDir")); if (null != dir) { File f = new File(dir); if (!f.isAbsolute()) { f = new File(core.getDataDir(), dir); } dirDescription = f.getAbsolutePath(); log.info("using spell directory: " + dirDescription); spellcheckerIndexDir = FSDirectory.open(f); } else { log.info("using RAM based spell directory"); } spellChecker = new SpellChecker(spellcheckerIndexDir); } catch (IOException e) { throw new RuntimeException("Cannot open SpellChecker index", e); } } /** * Processes the following query string parameters: q, extendedResults, cmd rebuild, * cmd reopen, accuracy, suggestionCount, restrictToField, and onlyMorePopular. */ @Override public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throws Exception { SolrParams p = req.getParams(); String words = p.get("q"); String cmd = p.get("cmd"); if (cmd != null) { cmd = cmd.trim(); if (cmd.equals("rebuild")) { rebuild(req); rsp.add("cmdExecuted", "rebuild"); } else if (cmd.equals("reopen")) { reopen(); rsp.add("cmdExecuted", "reopen"); } else { throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, "Unrecognized Command: " + cmd); } } // empty query string if (null == words || "".equals(words.trim())) { return; } IndexReader indexReader = null; String suggestionField = null; Float accuracy; int numSug; boolean onlyMorePopular; boolean extendedResults; try { accuracy = p.getFloat(ACCURACY, p.getFloat("accuracy", DEFAULT_ACCURACY)); spellChecker.setAccuracy(accuracy); } catch (NumberFormatException e) { throw new RuntimeException("Accuracy must be a valid positive float", e); } try { numSug = p.getInt(SUGGESTIONS, p.getInt("suggestionCount", DEFAULT_SUGGESTION_COUNT)); } catch (NumberFormatException e) { throw new RuntimeException("Spelling suggestion count must be a valid positive integer", e); } try { onlyMorePopular = p.getBool(POPULAR, DEFAULT_MORE_POPULAR); } catch (SolrException e) { throw new RuntimeException("'Only more popular' must be a valid boolean", e); } try { extendedResults = p.getBool(EXTENDED, DEFAULT_EXTENDED_RESULTS); } catch (SolrException e) { throw new RuntimeException("'Extended results' must be a valid boolean", e); } // when searching for more popular, a non null index-reader and // restricted-field are required if (onlyMorePopular || extendedResults) { indexReader = req.getSearcher().getReader(); suggestionField = termSourceField; } if (extendedResults) { rsp.add("numDocs", indexReader.numDocs()); SimpleOrderedMap<Object> results = new SimpleOrderedMap<Object>(); String[] wordz = words.split(" "); for (String word : wordz) { SimpleOrderedMap<Object> nl = new SimpleOrderedMap<Object>(); nl.add("frequency", indexReader.docFreq(new Term(suggestionField, word))); String[] suggestions = spellChecker.suggestSimilar(word, numSug, indexReader, suggestionField, onlyMorePopular); // suggestion array NamedList<Object> sa = new NamedList<Object>(); for (int i = 0; i < suggestions.length; i++) { // suggestion item SimpleOrderedMap<Object> si = new SimpleOrderedMap<Object>(); si.add("frequency", indexReader.docFreq(new Term(termSourceField, suggestions[i]))); sa.add(suggestions[i], si); } nl.add("suggestions", sa); results.add(word, nl); } rsp.add("result", results); } else { rsp.add("words", words); if (spellChecker.exist(words)) { rsp.add("exist", "true"); } else { rsp.add("exist", "false"); } String[] suggestions = spellChecker.suggestSimilar(words, numSug, indexReader, suggestionField, onlyMorePopular); rsp.add("suggestions", Arrays.asList(suggestions)); } } /** Returns a dictionary to be used when building the spell-checker index. * Override the method for custom dictionary */ protected Dictionary getDictionary(SolrQueryRequest req) { float threshold; try { threshold = req.getParams().getFloat(THRESHOLD, DEFAULT_DICTIONARY_THRESHOLD); } catch (NumberFormatException e) { throw new RuntimeException("Threshold must be a valid positive float", e); } IndexReader indexReader = req.getSearcher().getReader(); return new HighFrequencyDictionary(indexReader, termSourceField, threshold); } /** Rebuilds the SpellChecker index using values from the <code>termSourceField</code> from the * index pointed to by the current {@link IndexSearcher}. * Any word appearing in less that thresh documents will not be added to the spellcheck index. */ private void rebuild(SolrQueryRequest req) throws IOException, SolrException { if (null == termSourceField) { throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "can't rebuild spellchecker index without termSourceField configured"); } Dictionary dictionary = getDictionary(req); spellChecker.clearIndex(); spellChecker.indexDictionary(dictionary, new IndexWriterConfig(req.getCore().getSolrConfig().luceneMatchVersion, null), false); reopen(); } /** * Reopens the SpellChecker index directory. * Useful if an external process is responsible for building * the spell checker index. */ private void reopen() throws IOException { spellChecker.setSpellIndex(spellcheckerIndexDir); } //////////////////////// SolrInfoMBeans methods ////////////////////// @Override public String getVersion() { return "$Revision: 1197478 $"; } @Override public String getDescription() { return "The SpellChecker Solr request handler for SpellChecker index: " + dirDescription; } @Override public String getSourceId() { return "$Id: SpellCheckerRequestHandler.java 1197478 2011-11-04 10:10:03Z rmuir $"; } @Override public String getSource() { return "$URL: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_3_5/solr/core/src/java/org/apache/solr/handler/SpellCheckerRequestHandler.java $"; } @Override public URL[] getDocs() { return null; } }