/*
* 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.lucene.codecs;
import java.io.IOException;
import org.apache.lucene.index.SegmentReadState;
import org.apache.lucene.index.SegmentWriteState;
/**
* Encodes/decodes per-document score normalization values.
*/
public abstract class NormsFormat {
/** Sole constructor. (For invocation by subclass
* constructors, typically implicit.) */
protected NormsFormat() {
}
/** Returns a {@link NormsConsumer} to write norms to the
* index. */
public abstract NormsConsumer normsConsumer(SegmentWriteState state) throws IOException;
/**
* Returns a {@link NormsProducer} to read norms from the index.
* <p>
* NOTE: by the time this call returns, it must hold open any files it will
* need to use; else, those files may be deleted. Additionally, required files
* may be deleted during the execution of this call before there is a chance
* to open them. Under these circumstances an IOException should be thrown by
* the implementation. IOExceptions are expected and will automatically cause
* a retry of the segment opening logic with the newly revised segments.
*/
public abstract NormsProducer normsProducer(SegmentReadState state) throws IOException;
}