org.apache.felix.framework.util

Class WeakZipFileFactory.WeakZipFile

java.lang.Object

org.apache.felix.framework.util.WeakZipFileFactory.WeakZipFile

Enclosing class:

WeakZipFileFactory

public class WeakZipFileFactory.WeakZipFile
extends java.lang.Object

This class wraps a ZipFile to making it possible to weakly close it; this means the underlying zip file will be automatically reopened on demand if anyone tries to use it.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) class	WeakZipFileFactory.WeakZipFile.WeakZipInputStream This is an InputStream wrapper that will properly reopen the underlying zip file if it is weakly closed and create the underlying input stream.

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.ref.SoftReference<java.util.List<java.util.zip.ZipEntry>>	m_entries
private java.io.File	m_file
private Mutex	m_localMutex
private int	m_status
private long	m_timestamp
private java.util.zip.ZipFile	m_zipFile

Constructor Summary

Constructors

Modifier	Constructor and Description
private	WeakZipFile(java.io.File file) Constructor is private since instances need to be centrally managed.

Method Summary

Modifier and Type	Method and Description
private void	__close() This internal method is used to clear the zip file from the data structures and reset its state.
private void	__reopenZipFile() Thie internal method is used to reopen a weakly closed zip file.
private void	_closeWeakly() This method is used internally to weakly close a zip file.
void	close() This method permanently closes the zip file.
(package private) void	closeWeakly() Weakly closes the zip file, which means that it will be reopened if anyone tries to use it again.
private void	ensureZipFileIsOpen() This method ensures that the zip file associated with this weak zip file instance is actually open and acquires the local weak zip file mutex.
java.util.Enumeration<java.util.zip.ZipEntry>	entries() Returns an enumeration of zip entries from the zip file.
java.util.zip.ZipEntry	getEntry(java.lang.String name) Returns the specified entry from the zip file.
java.io.InputStream	getInputStream(java.util.zip.ZipEntry ze) Returns an input stream for the specified zip entry.

Methods inherited from class java.lang.Object

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

Field Detail

m_file

private final java.io.File m_file

m_localMutex

private final Mutex m_localMutex

m_zipFile

private java.util.zip.ZipFile m_zipFile

m_status

private int m_status

m_timestamp

private long m_timestamp

m_entries

private volatile java.lang.ref.SoftReference<java.util.List<java.util.zip.ZipEntry>> m_entries

Constructor Detail

WeakZipFile

private WeakZipFile(java.io.File file)
             throws java.io.IOException

Constructor is private since instances need to be centrally managed.

Parameters:

file - the target zip file.

Throws:

java.io.IOException - if the zip file could not be opened.

Method Detail

getEntry

public java.util.zip.ZipEntry getEntry(java.lang.String name)

Returns the specified entry from the zip file.

Parameters:

name - the name of the entry to return.

Returns:

the zip entry associated with the specified name or null if it does not exist.

entries

public java.util.Enumeration<java.util.zip.ZipEntry> entries()

Returns an enumeration of zip entries from the zip file.

Returns:

an enumeration of zip entries.

getInputStream

public java.io.InputStream getInputStream(java.util.zip.ZipEntry ze)
                                   throws java.io.IOException

Returns an input stream for the specified zip entry.

Parameters:

ze - the zip entry whose input stream is to be retrieved.

Returns:

an input stream to the zip entry.

Throws:

java.io.IOException - if the input stream cannot be opened.

closeWeakly

void closeWeakly()

Weakly closes the zip file, which means that it will be reopened if anyone tries to use it again.

_closeWeakly

private void _closeWeakly()

This method is used internally to weakly close a zip file. It should only be called when already holding the global lock, otherwise use closeWeakly().

close

public void close()
           throws java.io.IOException

This method permanently closes the zip file.

Throws:

java.io.IOException - if any error occurs while trying to close the zip file.

__close

private void __close()

This internal method is used to clear the zip file from the data structures and reset its state. It should only be called when holding the global and local mutexes.

ensureZipFileIsOpen

private void ensureZipFileIsOpen()

This method ensures that the zip file associated with this weak zip file instance is actually open and acquires the local weak zip file mutex. If the underlying zip file is closed, then the local mutex is released and an IllegalStateException is thrown. If the zip file is weakly closed, then it is reopened. If the zip file is already opened, then no additional action is necessary. If this method does not throw an exception, then the end result is the zip file member field is non-null and the local mutex has been acquired.

__reopenZipFile

private void __reopenZipFile()
                      throws java.io.IOException

Thie internal method is used to reopen a weakly closed zip file. It makes a best effort, but may fail and leave the zip file member field null. Any failure reopening a zip file results in it being permanently closed. This method should only be invoked when holding the global and local mutexes.

Throws:

java.io.IOException