package org.apache.lucene.index;
/**
* 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.
*/
/**
* Useful constants representing filenames and extensions used by lucene
*
* @author Bernhard Messer
* @version $rcs = ' $Id: Exp $ ' ;
*/
final class IndexFileNames {
/** Name of the index segment file */
static final String SEGMENTS = "segments";
/** Name of the generation reference file name */
static final String SEGMENTS_GEN = "segments.gen";
/** Name of the index deletable file (only used in
* pre-lockless indices) */
static final String DELETABLE = "deletable";
/** Extension of norms file */
static final String NORMS_EXTENSION = "nrm";
/**
* This array contains all filename extensions used by
* Lucene's index files, with two exceptions, namely the
* extension made up from <code>.f</code> + a number and
* from <code>.s</code> + a number. Also note that
* Lucene's <code>segments_N</code> files do not have any
* filename extension.
*/
static final String INDEX_EXTENSIONS[] = new String[] {
"cfs", "fnm", "fdx", "fdt", "tii", "tis", "frq", "prx", "del",
"tvx", "tvd", "tvf", "gen", "nrm"
};
/** File extensions of old-style index files */
static final String COMPOUND_EXTENSIONS[] = new String[] {
"fnm", "frq", "prx", "fdx", "fdt", "tii", "tis"
};
/** File extensions for term vector support */
static final String VECTOR_EXTENSIONS[] = new String[] {
"tvx", "tvd", "tvf"
};
/**
* Computes the full file name from base, extension and
* generation. If the generation is -1, the file name is
* null. If it's 0, the file name is <base><extension>.
* If it's > 0, the file name is <base>_<generation><extension>.
*
* @param base -- main part of the file name
* @param extension -- extension of the filename (including .)
* @param gen -- generation
*/
public static final String fileNameFromGeneration(String base, String extension, long gen) {
if (gen == -1) {
return null;
} else if (gen == 0) {
return base + extension;
} else {
return base + "_" + Long.toString(gen, Character.MAX_RADIX) + extension;
}
}
}
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