package org.apache.lucene.index.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.IOException;
import java.util.Set;

import org.apache.lucene.index.SegmentInfo;
import org.apache.lucene.index.SegmentWriteState;
import org.apache.lucene.index.SegmentReadState;
import org.apache.lucene.store.Directory;

/** @lucene.experimental */
public abstract class Codec {

  /** Unique name that's used to retrieve this codec when
   *  reading the index */
  public String name;

  /** Writes a new segment */
  public abstract FieldsConsumer fieldsConsumer(SegmentWriteState state) throws IOException;

  public static void debug(String s, String desc) {
    if (desc != null) {
      System.out.println(Thread.currentThread().getName()+ " [" + desc + "]:" + s);
    } else {
      System.out.println(Thread.currentThread().getName() + ": " + s);
    }
  }
  public static void debug(String s) {
    debug(s, null);
  }

  /** Reads a segment.  NOTE: by the time this call
   *  returns, it must hold open any files it will need to
   *  use; else, those files may be deleted. */
  public abstract FieldsProducer fieldsProducer(SegmentReadState state) throws IOException;

  /** Gathers files associated with this segment */
  public abstract void files(Directory dir, SegmentInfo segmentInfo, Set<String> files) throws IOException;

  /** Records all file extensions this codec uses */
  public abstract void getExtensions(Set<String> extensions);

  @Override
  public String toString() {
    return name;
  }
}