org.biojava.utils
Class FileAsList

java.lang.Object
  java.util.AbstractCollection
      java.util.AbstractList
          org.biojava.utils.FileAsList

All Implemented Interfaces:

Iterable, Collection, List, Commitable

public abstract class FileAsList
extends AbstractList
implements Commitable

FileAsList creates a writable List implementation backed by a random access file. There is a restriction on the record length that the string representation of that integer may not be longer than 4 bytes. This is because a fixed 4 byte leader is used to encode the record length in the file.

Author:

Matthew Pocock, Keith James, Greg Cox

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

FileAsList(File mappedFile, boolean mutable)
Creates a new FileAsList instance from an existing backing file.

FileAsList(File mappedFile, int recordLength)
Creates a new FileAsList and corresponding backing file.

Method Summary

boolean	add(Object o)
void	clear()
void	commit() commit commits pending changes.
protected abstract void	generateRecord(byte[] buffer, Object item)
Object	get(int indx)
abstract Comparator	getComparator()
Iterator	iterator()
protected abstract Object	parseRecord(byte[] buffer)
byte[]	rawGet(int indx) rawGet reads the record at the specified index as a raw byte array.
void	rollback() rollback reverses pending changes to restore initial (or prior commit) state.
Object	set(int indx, Object o) This always returns null, not the previous object.
int	size()

Methods inherited from class java.util.AbstractList

add, addAll, equals, hashCode, indexOf, lastIndexOf, listIterator, listIterator, remove, removeRange, subList

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Constructor Detail

FileAsList

public FileAsList(File mappedFile,
                  int recordLength)
           throws IOException

Creates a new FileAsList and corresponding backing file.

Parameters:

mappedFile - a File used to back the list. This file must not already exist.

recordLength - an int byte record length.

Throws:

IOException - if an error occurs.

FileAsList

public FileAsList(File mappedFile,
                  boolean mutable)
           throws IOException

Creates a new FileAsList instance from an existing backing file.

Parameters:

mappedFile - a File used to back the list. This file must already exist.

mutable - true if this list should support edits, false otherwise

Throws:

IOException - if an error occurs.

Method Detail

rawGet

public byte[] rawGet(int indx)

rawGet reads the record at the specified index as a raw byte array.

Parameters:

indx - an int list index.

Returns:

a byte [] array containing the raw record data.

get

public Object get(int indx)

Specified by:

get in interface List

Specified by:

get in class AbstractList

size

public int size()

Specified by:

size in interface Collection

Specified by:

size in interface List

Specified by:

size in class AbstractCollection

add

public boolean add(Object o)

Specified by:

add in interface Collection

Specified by:

add in interface List

Overrides:

add in class AbstractList

set

public Object set(int indx,
                  Object o)

This always returns null, not the previous object.

Specified by:

set in interface List

Overrides:

set in class AbstractList

clear

public void clear()

Specified by:

clear in interface Collection

Specified by:

clear in interface List

Overrides:

clear in class AbstractList

commit

public void commit()

Description copied from interface: Commitable

commit commits pending changes.

Specified by:

commit in interface Commitable

rollback

public void rollback()

Description copied from interface: Commitable

rollback reverses pending changes to restore initial (or prior commit) state. This always succededs or raises an unchecked exception.

Specified by:

rollback in interface Commitable

parseRecord

protected abstract Object parseRecord(byte[] buffer)

generateRecord

protected abstract void generateRecord(byte[] buffer,
                                       Object item)
                                throws IOException

Throws:

IOException

getComparator

public abstract Comparator getComparator()

iterator

public Iterator iterator()

Specified by:

iterator in interface Iterable

Specified by:

iterator in interface Collection

Specified by:

iterator in interface List

Overrides:

iterator in class AbstractList