com.sun.cldc.jna
Class NativeLibrary

java.lang.Object
  com.sun.cldc.jna.NativeLibrary

public class NativeLibrary
extends Object

Represents a handle to a runtime library (for example, as returned by the POSIX function "dlopen" http://www.opengroup.org/onlinepubs/009695399/functions/dlopen.html

Differences from JNA

• Throws RuntimeExceptions instead of UnsatisfiedLinkErrors. Are link errors really "unrecoverable"? Platform independant code might want to work around missing functions.
• Search paths unimplemented
• Calling conventions unimplemented
• no finalization in cldc, need to call dispose() explicitly (could add a shutdownhook though).
• no parseVersion();
• no getFile()

Method Summary

void	dispose() Close the library, as in dlclose.
static String	errorStr() Get any error message provided by the platform (as in dlerror).
BlockingFunction	getBlockingFunction(String funcName) Dynamically look up a blocking native function by name.
static NativeLibrary	getDefaultInstance() Return reference to the "default" library.
Function	getFunction(String funcName) Dynamically look up a native function by name.
VarPointer	getGlobalVariableAddress(String varName, int size) Dynamically look up a native variable by name.
static NativeLibrary	getInstance(String name) Look up a native libray named "name".
String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

getFunction

public Function getFunction(String funcName)

Dynamically look up a native function by name. WARNING: Do NOT use for calling C functions that may block (or take a "long" time). Use the "blocking" version instead. Look up the symbol in the specified library

Parameters:

funcName -

Returns:

an object that can be used to call the named function

Throws:

RuntimeException - if there is no function by that name.

getBlockingFunction

public BlockingFunction getBlockingFunction(String funcName)

Dynamically look up a blocking native function by name. Look up the symbol in the specified library

Parameters:

funcName -

Returns:

an object that can be used to call the named function

Throws:

RuntimeException - if there is no function by that name.

getGlobalVariableAddress

public VarPointer getGlobalVariableAddress(String varName,
                                           int size)

Dynamically look up a native variable by name. Look up the symbol in the default list of loaded libraries.

Parameters:

varName -

size - the size of the variable in bytes

Returns:

an objecta that can be used to call the named function

Throws:

RuntimeException - if there is no function by that name.

getInstance

public static NativeLibrary getInstance(String name)

Look up a native libray named "name". Load if not loaded. Name can be a path or a libray name. The Library will be looked up in a platform-dependant manor.

Parameters:

name - short library name, full file name, or path to the library file

Returns:

NativeLibrary

getDefaultInstance

public static NativeLibrary getDefaultInstance()

Return reference to the "default" library. All lookups in the default library will follow the platform's default getFunction semantics. The Library will be looked up in a platform-dependant maner.

Returns:

NativeLibrary

dispose

public void dispose()

Close the library, as in dlclose.

Throws:

RuntimeException - if dlcose fails

errorStr

public static String errorStr()

Get any error message provided by the platform (as in dlerror). If no error, then return null. Note that calling this method clears the error state, so calling two times without calling any other platform getFunction method (getInstance(), getFunction(), getGlobalVariableAddress(), dispose()) will result in returning null.

Returns:

String (may be null)

toString

public String toString()

Description copied from class: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.