de.schlichtherle.io
Class InputArchiveMetaData

java.lang.Object
  de.schlichtherle.io.InputArchiveMetaData

public final class InputArchiveMetaData
extends Object

This class is not intended for public use! It's only public in order to implement ArchiveDrivers.

Annotates an InputArchive with the methods required for safe reading of archive entries. As an implication of this, it's also responsible for the synchronization of the streams between multiple threads.

Since:

TrueZIP 6.0

Version:

$Id: InputArchiveMetaData.java 06f3ba684701 2010/11/04 01:15:55 christian $

Author:

Christian Schlichtherle

Nested Class Summary

private class

InputArchiveMetaData.EntryInputStream An InputStream to read the entry data from an InputArchive.

Field Summary

private Archive	archive The archive which uses this instance.
private static String	CLASS_NAME
private InputArchive	inArchive
private static Logger	logger
private boolean	stopped
private Map	streams The pool of all open entry streams.

Constructor Summary

InputArchiveMetaData(Archive archive, InputArchive inArchive)
Creates a new instance of InputArchiveMetaData and sets itself as the meta data for the given input archive.

Method Summary

(package private) ArchiveException	closeAllInputStreams(ArchiveException exceptionChain) Closes and disconnects all entry streams for the archive containing this metadata object.
(package private) InputStream	createInputStream(ArchiveEntry entry, ArchiveEntry dstEntry)
private int	threadStreams() Returns the number of streams opened by the current thread.
(package private) int	waitAllInputStreamsByOtherThreads(long timeout) Waits until all entry streams which have been opened (and not yet closed) by all other threads are closed or a timeout occurs.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CLASS_NAME

private static final String CLASS_NAME

See Also:

Constant Field Values

logger

private static final Logger logger

archive

private final Archive archive

The archive which uses this instance. Although this field is actually never used in this class, it makes an archive controller strongly reachable from any entry stream in use by any thread. This is required to keep the archive controller from being garbarge collected meanwhile.

Detail: While this is really required for input streams for archives which are unmodified, it's actually not required for output streams, since the archive file system is touched for these streams anyway, which in turn schedules the archive controller for the next update, which in turn prevents it from being garbage collected. However, it's provided for symmetry between input archive meta data and output archive meta data.

inArchive

private final InputArchive inArchive

streams

private final Map streams

The pool of all open entry streams. This is implemented as a map where the keys are the streams and the value is the current thread. If File.isLenient() is true, then the map is actually instantiated as a WeakHashMap. Otherwise, it's a HashMap. The weak hash map allows the garbage collector to pick up an entry stream if there are no more references to it. This reduces the likeliness of an ArchiveBusyWarningException in case a sloppy client application has forgot to close a stream before calling File.umount() or File.update().

stopped

private volatile boolean stopped

Constructor Detail

InputArchiveMetaData

InputArchiveMetaData(Archive archive,
                     InputArchive inArchive)

Creates a new instance of InputArchiveMetaData and sets itself as the meta data for the given input archive.

Method Detail

createInputStream

InputStream createInputStream(ArchiveEntry entry,
                              ArchiveEntry dstEntry)
                        throws IOException

Throws:

IOException

waitAllInputStreamsByOtherThreads

int waitAllInputStreamsByOtherThreads(long timeout)

Waits until all entry streams which have been opened (and not yet closed) by all other threads are closed or a timeout occurs. If the current thread is interrupted while waiting, a warning message is logged using java.util.logging and this method returns.

Unless otherwise prevented, another thread could immediately open another stream upon return of this method. So there is actually no guarantee that really all streams are closed upon return of this method - use carefully!

Returns:

The number of all open streams.

threadStreams

private int threadStreams()

Returns the number of streams opened by the current thread.

closeAllInputStreams

ArchiveException closeAllInputStreams(ArchiveException exceptionChain)

Closes and disconnects all entry streams for the archive containing this metadata object. Disconnecting means that any subsequent operation on the entry streams will throw an IOException, with the exception of their close() method.