001/*
002 *                    BioJava development code
003 *
004 * This code may be freely distributed and modified under the
005 * terms of the GNU Lesser General Public Licence.  This should
006 * be distributed with the code.  If you do not have a copy,
007 * see:
008 *
009 *      http://www.gnu.org/copyleft/lesser.html
010 *
011 * Copyright for this code is held jointly by the individual
012 * authors.  These should be listed in @author doc comments.
013 *
014 * For more information on the BioJava project and its aims,
015 * or to join the biojava-l mailing list, visit the home page
016 * at:
017 *
018 *      http://www.biojava.org/
019 *
020 */
021
022package org.biojava.bio.seq.db;
023
024import java.io.File;
025
026/**
027 * This defines an index entry for an individual sequence within a set of
028 * indexed files.
029 *
030 * @author Matthew Pocock
031 */
032public interface Index {
033  /**
034   * The file to retrieve from.
035   *
036   * @return the File containing this Sequence
037   */
038  File getFile();
039  
040  /**
041   * Skipping this number of bytes through the file should put the file pointer
042   * to the first byte of the sequence.
043   *
044   * @return the offset within the file
045   */
046  long getStart();
047  
048  /**
049   * The entry can be slurped out of the file by grabbing length bytes from
050   * start. If the length can't be read from a store then this method should
051   * return -1.
052   * 
053   * @return the length in bytes of this indexed entry
054   */
055  int getLength();
056  
057  /**
058   * The ID of the sequence at this position in this file.
059   *
060   * @return the ID of the indexed Sequence
061   */
062  String getID();
063}