package org.apache.lucene.codecs;
/*
* 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.
*/
import java.io.Closeable;
import java.io.IOException;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.DocValues;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.index.MergeState;
import org.apache.lucene.index.DocValues.Type;
/**
* Abstract API that consumes per document values. Concrete implementations of
* this convert field values into a Codec specific format during indexing.
* <p>
* The {@link PerDocConsumer} API is accessible through the
* {@link PostingsFormat} - API providing per field consumers and producers for inverted
* data (terms, postings) as well as per-document data.
*
* @lucene.experimental
*/
public abstract class PerDocConsumer implements Closeable {
/** Sole constructor. (For invocation by subclass
* constructors, typically implicit.) */
protected PerDocConsumer() {
}
/** Adds a new DocValuesField */
public abstract DocValuesConsumer addValuesField(DocValues.Type type, FieldInfo field)
throws IOException;
/**
* Consumes and merges the given {@link PerDocProducer} producer
* into this consumers format.
*/
public void merge(MergeState mergeState) throws IOException {
final DocValues[] docValues = new DocValues[mergeState.readers.size()];
for (FieldInfo fieldInfo : mergeState.fieldInfos) {
mergeState.fieldInfo = fieldInfo; // set the field we are merging
if (canMerge(fieldInfo)) {
for (int i = 0; i < docValues.length; i++) {
docValues[i] = getDocValuesForMerge(mergeState.readers.get(i), fieldInfo);
}
Type docValuesType = getDocValuesType(fieldInfo);
assert docValuesType != null;
final DocValuesConsumer docValuesConsumer = addValuesField(docValuesType, fieldInfo);
assert docValuesConsumer != null;
docValuesConsumer.merge(mergeState, docValues);
}
}
}
/**
* Returns a {@link DocValues} instance for merging from the given reader for the given
* {@link FieldInfo}. This method is used for merging and uses
* {@link AtomicReader#docValues(String)} by default.
* <p>
* To enable {@link DocValues} merging for different {@link DocValues} than
* the default override this method accordingly.
* <p>
*/
protected DocValues getDocValuesForMerge(AtomicReader reader, FieldInfo info) throws IOException {
return reader.docValues(info.name);
}
/**
* Returns <code>true</code> iff the given field can be merged ie. has {@link DocValues}.
* By default this method uses {@link FieldInfo#hasDocValues()}.
* <p>
* To enable {@link DocValues} merging for different {@link DocValues} than
* the default override this method accordingly.
* <p>
*/
protected boolean canMerge(FieldInfo info) {
return info.hasDocValues();
}
/**
* Returns the {@link DocValues} {@link Type} for the given {@link FieldInfo}.
* By default this method uses {@link FieldInfo#getDocValuesType()}.
* <p>
* To enable {@link DocValues} merging for different {@link DocValues} than
* the default override this method accordingly.
* <p>
*/
protected Type getDocValuesType(FieldInfo info) {
return info.getDocValuesType();
}
/**
* Called during indexing if the indexing session is aborted due to a unrecoverable exception.
* This method should cleanup all resources.
*/
public abstract void abort();
@Override
public abstract void close() throws IOException;
}