org.deeplearning4j.text.sentenceiterator.BasicResultSetIterator Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.deeplearning4j.text.sentenceiterator;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* Primitive iterator over a SQL ResultSet
*
* Please note: for reset functionality, the underlying JDBC ResultSet must not be of TYPE_FORWARD_ONLY
* To achieve this using postgres you can make your query using: connection.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
*
* This class is designed in a similar fashion to org.deeplearning4j.text.sentenceiterator.BasicLineIterator
*
* @author Brad Heap [email protected]
*/
public class BasicResultSetIterator implements SentenceIterator {
private ResultSet rs;
private String columnName;
private SentencePreProcessor preProcessor;
private boolean nextCalled; // we use this to ensure that next is only called once by hasNext() to ensure we don't skip over data
private boolean resultOfNext;
public BasicResultSetIterator(ResultSet rs, String columnName) {
this.rs = rs;
this.columnName = columnName;
this.nextCalled = false;
this.resultOfNext = false;
}
public synchronized String nextSentence() {
try {
if (!nextCalled) { // move onto the next row if we haven't yet
rs.next();
} else {
nextCalled = false; // reset that next has been called for next time we call nextSentence() or hasNext()
}
return (preProcessor != null) ? this.preProcessor.preProcess(rs.getString(columnName))
: rs.getString(columnName);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public synchronized boolean hasNext() {
try {
if (!nextCalled) {
resultOfNext = rs.next();
nextCalled = true;
}
return resultOfNext;
} catch (SQLException e) {
return false;
}
}
public synchronized void reset() {
try {
rs.beforeFirst();
nextCalled = false;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public void finish() {
try {
rs.close();
} catch (SQLException e) {
// do nothing here
}
}
public SentencePreProcessor getPreProcessor() {
return preProcessor;
}
public void setPreProcessor(SentencePreProcessor preProcessor) {
this.preProcessor = preProcessor;
}
}