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.
*/
import org.apache.lucene.index.codecs.Codec; // for javadocs
/**
* This class contains useful constants representing filenames and extensions
* used by lucene, as well as convenience methods for querying whether a file
* name matches an extension ({@link #matchesExtension(String, String)
* matchesExtension}), as well as generating file names from a segment name,
* generation and extension (
* {@link #fileNameFromGeneration(String, String, long) fileNameFromGeneration},
* {@link #segmentFileName(String, String, String) segmentFileName}).
*
* <p><b>NOTE</b>: extensions used by codecs are not
* listed here. You must interact with the {@link Codec}
* directly.
*
* @lucene.internal
*/
public final class IndexFileNames {
/** Name of the index segment file */
public static final String SEGMENTS = "segments";
/** Extension of gen file */
public static final String GEN_EXTENSION = "gen";
/** Name of the generation reference file name */
public static final String SEGMENTS_GEN = "segments." + GEN_EXTENSION;
/** Extension of norms file */
public static final String NORMS_EXTENSION = "nrm";
/** Extension of stored fields index file */
public static final String FIELDS_INDEX_EXTENSION = "fdx";
/** Extension of stored fields file */
public static final String FIELDS_EXTENSION = "fdt";
/** Extension of vectors fields file */
public static final String VECTORS_FIELDS_EXTENSION = "tvf";
/** Extension of vectors documents file */
public static final String VECTORS_DOCUMENTS_EXTENSION = "tvd";
/** Extension of vectors index file */
public static final String VECTORS_INDEX_EXTENSION = "tvx";
/** Extension of compound file */
public static final String COMPOUND_FILE_EXTENSION = "cfs";
/** Extension of compound file for doc store files*/
public static final String COMPOUND_FILE_STORE_EXTENSION = "cfx";
/** Extension of deletes */
public static final String DELETES_EXTENSION = "del";
/** Extension of field infos */
public static final String FIELD_INFOS_EXTENSION = "fnm";
/** Extension of separate norms */
public static final String SEPARATE_NORMS_EXTENSION = "s";
/**
* This array contains all filename extensions used by
* Lucene's index files, with one exception, namely the
* extension made up from <code>.s</code> + a number.
* Also note that Lucene's <code>segments_N</code> files
* do not have any filename extension.
*/
public static final String INDEX_EXTENSIONS[] = new String[] {
COMPOUND_FILE_EXTENSION,
FIELD_INFOS_EXTENSION,
FIELDS_INDEX_EXTENSION,
FIELDS_EXTENSION,
DELETES_EXTENSION,
VECTORS_INDEX_EXTENSION,
VECTORS_DOCUMENTS_EXTENSION,
VECTORS_FIELDS_EXTENSION,
GEN_EXTENSION,
NORMS_EXTENSION,
COMPOUND_FILE_STORE_EXTENSION,
};
public static final String[] STORE_INDEX_EXTENSIONS = new String[] {
VECTORS_INDEX_EXTENSION,
VECTORS_FIELDS_EXTENSION,
VECTORS_DOCUMENTS_EXTENSION,
FIELDS_INDEX_EXTENSION,
FIELDS_EXTENSION
};
public static final String[] NON_STORE_INDEX_EXTENSIONS = new String[] {
FIELD_INFOS_EXTENSION,
NORMS_EXTENSION
};
static final String COMPOUND_EXTENSIONS_NOT_CODEC[] = new String[] {
FIELD_INFOS_EXTENSION,
FIELDS_INDEX_EXTENSION,
FIELDS_EXTENSION,
};
/** File extensions for term vector support */
public static final String VECTOR_EXTENSIONS[] = new String[] {
VECTORS_INDEX_EXTENSION,
VECTORS_DOCUMENTS_EXTENSION,
VECTORS_FIELDS_EXTENSION
};
/**
* 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>.<ext>. If it's > 0, the file name is
* <base>_<gen>.<ext>.<br>
* <b>NOTE:</b> .<ext> is added to the name only if <code>ext</code> is
* not an empty string.
*
* @param base main part of the file name
* @param ext extension of the filename
* @param gen generation
*/
public static String fileNameFromGeneration(String base, String ext, long gen) {
if (gen == SegmentInfo.NO) {
return null;
} else if (gen == SegmentInfo.WITHOUT_GEN) {
return segmentFileName(base, "", ext);
} else {
// The '6' part in the length is: 1 for '.', 1 for '_' and 4 as estimate
// to the gen length as string (hopefully an upper limit so SB won't
// expand in the middle.
StringBuilder res = new StringBuilder(base.length() + 6 + ext.length())
.append(base).append('_').append(Long.toString(gen, Character.MAX_RADIX));
if (ext.length() > 0) {
res.append('.').append(ext);
}
return res.toString();
}
}
/**
* Returns true if the provided filename is one of the doc store files (ends
* with an extension in {@link #STORE_INDEX_EXTENSIONS}).
*/
public static boolean isDocStoreFile(String fileName) {
if (fileName.endsWith(COMPOUND_FILE_STORE_EXTENSION))
return true;
for (String ext : STORE_INDEX_EXTENSIONS) {
if (fileName.endsWith(ext))
return true;
}
return false;
}
/**
* Returns a file name that includes the given segment name, your own custom
* name and extension. The format of the filename is:
* <segmentName>(_<name>)(.<ext>).
* <p>
* <b>NOTE:</b> .<ext> is added to the result file name only if
* <code>ext</code> is not empty.
* <p>
* <b>NOTE:</b> _<name> is added to the result file name only if
* <code>name</code> is not empty.
* <p>
* <b>NOTE:</b> all custom files should be named using this method, or
* otherwise some structures may fail to handle them properly (such as if they
* are added to compound files).
*/
public static String segmentFileName(String segmentName, String name, String ext) {
if (ext.length() > 0 || name.length() > 0) {
assert !ext.startsWith(".");
StringBuilder sb = new StringBuilder(segmentName.length() + 2 + name.length() + ext.length());
sb.append(segmentName);
if (name.length() > 0) {
sb.append('_').append(name);
}
if (ext.length() > 0) {
sb.append('.').append(ext);
}
return sb.toString();
} else {
return segmentName;
}
}
/**
* Returns true if the given filename ends with the given extension. One
* should provide a <i>pure</i> extension, withouth '.'.
*/
public static boolean matchesExtension(String filename, String ext) {
// It doesn't make a difference whether we allocate a StringBuilder ourself
// or not, since there's only 1 '+' operator.
return filename.endsWith("." + ext);
}
/**
* Strips the segment name out of the given file name. If you used
* {@link #segmentFileName} or {@link #fileNameFromGeneration} to create your
* files, then this method simply removes whatever comes before the first '.',
* or the second '_' (excluding both).
*
* @return the filename with the segment name removed, or the given filename
* if it does not contain a '.' and '_'.
*/
public static String stripSegmentName(String filename) {
// If it is a .del file, there's an '_' after the first character
int idx = filename.indexOf('_', 1);
if (idx == -1) {
// If it's not, strip everything that's before the '.'
idx = filename.indexOf('.');
}
if (idx != -1) {
filename = filename.substring(idx);
}
return filename;
}
}