Package com.kenai.jffi

Class Library

java.lang.Object

com.kenai.jffi.Library

public final class Library
extends java.lang.Object

Represents a native library

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	Library.DefaultLibrary	A handle to the current process

Field Summary

Fields

Modifier and Type	Field	Description
private static java.util.Map<java.lang.String,java.lang.ref.WeakReference<Library>>	cache	A cache of opened libraries
private int	disposed	Indicates whether this library has been disposed of.
private Foreign	foreign	A handle to the foreign interface to keep it alive as long as this object is alive
static int	GLOBAL	All symbols in the library are made available to other libraries
private long	handle	The native dl/LoadLibrary handle
private static java.lang.ThreadLocal<java.lang.String>	lastError	Stores the last error returned by a dlopen or dlsym call
static int	LAZY	Perform lazy binding.
static int	LOCAL	Symbols in this library are not made available to other libraries
private static java.lang.Object	lock	A lock used to serialize all dlopen/dlsym calls
private java.lang.String	name	The name of this Library
static int	NOW	Resolve all symbols when loading the library
private static java.util.concurrent.atomic.AtomicIntegerFieldUpdater<Library>	UPDATER

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Library(Foreign foreign, java.lang.String name, long address)

Method Summary

Modifier and Type	Method	Description
private static long	dlopen(Foreign foreign, java.lang.String name, int flags)	Internal wrapper around dlopen.
protected void	finalize()
static Library	getCachedInstance(java.lang.String name, int flags)	Gets a handle for the named library.
static Library	getDefault()	Gets a handle to the default library.
static java.lang.String	getLastError()	Gets the current error string from dlopen/LoadLibrary.
long	getSymbolAddress(java.lang.String name)	Gets the address of a symbol within the Library.
static Library	openLibrary(java.lang.String name, int flags)	Gets a handle for the named library.

Methods inherited from class java.lang.Object

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

Field Detail

cache

private static final java.util.Map<java.lang.String,java.lang.ref.WeakReference<Library>> cache

A cache of opened libraries

lock

private static final java.lang.Object lock

A lock used to serialize all dlopen/dlsym calls

lastError

private static final java.lang.ThreadLocal<java.lang.String> lastError

Stores the last error returned by a dlopen or dlsym call

LAZY

public static final int LAZY

Perform lazy binding. Only resolve symbols as needed

See Also:

Constant Field Values

NOW

public static final int NOW

Resolve all symbols when loading the library

See Also:

Constant Field Values

LOCAL

public static final int LOCAL

Symbols in this library are not made available to other libraries

See Also:

Constant Field Values

GLOBAL

public static final int GLOBAL

All symbols in the library are made available to other libraries

See Also:

Constant Field Values

handle

private final long handle

The native dl/LoadLibrary handle

name

private final java.lang.String name

The name of this Library

foreign

private final Foreign foreign

A handle to the foreign interface to keep it alive as long as this object is alive

disposed

private volatile int disposed

Indicates whether this library has been disposed of.

UPDATER

private static final java.util.concurrent.atomic.AtomicIntegerFieldUpdater<Library> UPDATER

Constructor Detail

Library

private Library(Foreign foreign,
                java.lang.String name,
                long address)

Method Detail

dlopen

private static long dlopen(Foreign foreign,
                           java.lang.String name,
                           int flags)

Internal wrapper around dlopen. If the library open fails, then this stores the native error in a thread local variable for later retrieval.

Parameters:

name - The name of the library to open

flags - The flags to pass to dlopen

Returns:

The native handle for the opened library, or 0 if it failed to open.

getDefault

public static final Library getDefault()

Gets a handle to the default library.

Returns:

A Library instance representing the default library.

getCachedInstance

public static final Library getCachedInstance(java.lang.String name,
                                              int flags)

Gets a handle for the named library.

Parameters:

name - The name or path of the library to open.

flags - The library flags (e.g. LAZY, NOW, LOCAL, GLOBAL)

Returns:

A Library instance representing the named library, or null if the library could not be opened.

openLibrary

public static final Library openLibrary(java.lang.String name,
                                        int flags)

Gets a handle for the named library. Note This will not cache the instance, nor will it return a cached instance. Only use when you really need a new handle for the library.

Parameters:

name - The name or path of the library to open.

flags - The library flags (e.g. LAZY, NOW, LOCAL, GLOBAL)

Returns:

A Library instance representing the named library, or null if the library cannot be opened.

getSymbolAddress

public final long getSymbolAddress(java.lang.String name)

Gets the address of a symbol within the Library.

Parameters:

name - The name of the symbol to locate.

Returns:

The address of the symbol within the current address space.

getLastError

public static final java.lang.String getLastError()

Gets the current error string from dlopen/LoadLibrary.

Returns:

A String describing the last error.

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable