scriptella.driver.lucene.LuceneConnection Maven / Gradle / Ivy
/*
* Copyright 2006-2012 The Scriptella Project Team.
*
* Licensed 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 scriptella.driver.lucene;
import org.apache.lucene.index.IndexReader;
import scriptella.driver.text.TextProviderException;
import scriptella.spi.AbstractConnection;
import scriptella.spi.ConnectionParameters;
import scriptella.spi.ParametersCallback;
import scriptella.spi.ProviderException;
import scriptella.spi.QueryCallback;
import scriptella.spi.Resource;
import scriptella.util.IOUtils;
import java.io.IOException;
import java.io.Reader;
import java.net.URL;
import java.util.Set;
import java.util.TreeSet;
/**
* Represents a connection to a Lucene index.
* For configuration details and examples see overview page.
*
* @author Kirill Volgin
* @version 1.0
*/
public class LuceneConnection extends AbstractConnection {
private static final String[] EMPTY_ARRAY = new String[] {};
private URL url;
private Set fields;
private static final String DEFAULT_FIELD = "contents";
private Boolean useMultiFieldQueryParser;
private Boolean useLowercaseExpandedTerms;
/**
* Instantiates a new connection to Lucene Query.
* @param parameters connection parameters.
*/
public LuceneConnection(ConnectionParameters parameters) {
super(Driver.DIALECT_IDENTIFIER, parameters);
url = parameters.getResolvedUrl();
parseFields((String)parameters.getProperty("fields"));
useMultiFieldQueryParser = parameters.getBooleanProperty("useMultiFieldQueryParser", false);
useLowercaseExpandedTerms = parameters.getBooleanProperty("useLowercaseExpandedTerms", true);
}
public void executeScript(Resource scriptContent, ParametersCallback parametersCallback) throws ProviderException {
throw new UnsupportedOperationException("Script execution is not supported yet");
}
/**
* Executes a query specified by its content.
*
*
* @param queryContent query content.
* @param parametersCallback callback to get parameter values.
* @param queryCallback callback to call for each result set element produced by this query.
* @see #executeScript(scriptella.spi.Resource, scriptella.spi.ParametersCallback)
*/
public synchronized void executeQuery(Resource queryContent, ParametersCallback parametersCallback, QueryCallback queryCallback) throws ProviderException{
LuceneQuery query = null;
Reader r;
try {
r = queryContent.open();
} catch (IOException e) {
throw new TextProviderException("Cannot open a query for reading", e);
}
try {
query = new LuceneQuery(url.getFile(), parametersCallback, queryCallback);
query.execute(r, fields, useMultiFieldQueryParser, useLowercaseExpandedTerms);
} finally {
IOUtils.closeSilently(query);
}
}
/**
* Closes the connection and releases all related resources.
*/
public void close() throws ProviderException {
}
/**
* Parses given string to find default Lucene fields for search query
* @param s given string
*/
private void parseFields(String s) {
if (s == null) {
fields = new TreeSet();
fields.add(DEFAULT_FIELD);
} else {
String[] strings = (' '+s+' ').split(",");
fields = new TreeSet();
for (int i = 0; i < strings.length; i++) {
strings[i]=strings[i].trim();
if ("".equals(strings[i])) {
fields.add(DEFAULT_FIELD); //default value
} else if ("*".contains(strings[i])) {
try {
IndexReader ir = IndexReader.open(url.getFile());
fields.addAll(ir.getFieldNames(IndexReader.FieldOption.INDEXED));
} catch (IOException e) {
throw new LuceneProviderException("Failed to open lucene index.",e);
}
} else {
fields.add(strings[i]);
}
}
}
}
}