Package jnr.ffi
Class LibraryLoader<T>
java.lang.Object
jnr.ffi.LibraryLoader<T>
Loads a native library and maps it to a java interface.
Example usage
public interface LibC {
int puts(String str);
}
LibC libc = LibraryLoader.create(LibC.class).load("c");
libc.puts("Hello, World");
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Field Summary
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionconvention
(CallingConvention convention) Sets the native function calling convention.static <T> LibraryLoader
<T> Creates a newLibraryLoader
instance.final LibraryLoader
<T> Turns off lazy propagation of load failures.Adds a library to be loaded.load()
Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.protected abstract T
loadLibrary
(Class<T> interfaceClass, Collection<String> libraryNames, Collection<String> searchPaths, Map<LibraryOption, Object> options, boolean failImmediately) Implemented by FFI providers to load the actual library.static <T> T
loadLibrary
(Class<T> interfaceClass, Map<LibraryOption, ?> libraryOptions, String... libraryNames) Same as callingloadLibrary(Class, Map, Map, String...)
with an empty search path map.static <T> T
loadLibrary
(Class<T> interfaceClass, Map<LibraryOption, ?> libraryOptions, Map<String, List<String>> searchPaths, String... libraryNames) Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.<J> LibraryLoader
<T> map
(Class<? extends J> javaType, DataConverter<? extends J, ?> dataConverter) <J> LibraryLoader
<T> map
(Class<? extends J> javaType, FromNativeConverter<? extends J, ?> fromNativeConverter) Adds a custom java type mapping.<J> LibraryLoader
<T> map
(Class<? extends J> javaType, ToNativeConverter<? extends J, ?> toNativeConverter) Adds a custom java type mapping.Adds a function name mapping to use when resolving symbols in this library.mapper
(FunctionMapper functionMapper) Adds a function mapper to use when resolving symbols in this library.mapper
(SignatureTypeMapper typeMapper) Adds a type mapper to use when resolving method parameter and result types.mapper
(TypeMapper typeMapper) Adds a type mapper to use when resolving method parameter and result types.option
(LibraryOption option, Object value) Sets an option when loading libraries.static boolean
saveError
(Map<LibraryOption, ?> options, boolean methodHasSave, boolean methodHasIgnore) When either theSaveError
orIgnoreError
annotations are used, the following matrix applies: (SL = save at library level, IM = ignore at method level, etc)Adds a path to search for libraries.Add the default library to the search order.final LibraryLoader
<T> stdcall()
Sets the calling convention of the library to the Windows stdcall calling convention
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Field Details
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DEFAULT_LIBRARY
- See Also:
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Constructor Details
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LibraryLoader
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Method Details
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create
Creates a newLibraryLoader
instance.- Type Parameters:
T
- The library type.- Parameters:
interfaceClass
- the interface that describes the native library functions- Returns:
- A
LibraryLoader
instance.
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saveError
public static boolean saveError(Map<LibraryOption, ?> options, boolean methodHasSave, boolean methodHasIgnore) When either theSaveError
orIgnoreError
annotations are used, the following matrix applies: (SL = save at library level, IM = ignore at method level, etc)| none | SL | IL | SL+IL| ------------------------------------- none | save | save | ignr | save | SM | save | save | save | save | IM | ignr | ignr | ignr | ignr | SM + IM | save | save | save | save |
- Parameters:
options
- optionsmethodHasSave
- whether the method has error-saving enabledmethodHasIgnore
- whether the method ignores errors- Returns:
- true if the error was saved, false otherwise
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loadLibrary
public static <T> T loadLibrary(Class<T> interfaceClass, Map<LibraryOption, ?> libraryOptions, Map<String, List<String>> searchPaths, String... libraryNames) Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.- Type Parameters:
T
- the interface type.- Parameters:
interfaceClass
- the interface that describes the native library interfacelibraryOptions
- optionssearchPaths
- a map of library names to paths that should be searchedlibraryNames
- the name of the library to load- Returns:
- an instance of
interfaceclass
that will call the native methods.
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loadLibrary
public static <T> T loadLibrary(Class<T> interfaceClass, Map<LibraryOption, ?> libraryOptions, String... libraryNames) Same as callingloadLibrary(Class, Map, Map, String...)
with an empty search path map.- Type Parameters:
T
- the interface type- Parameters:
interfaceClass
- the interface to implementlibraryOptions
- optionslibraryNames
- names to try when searching for the library- Returns:
- a new object implementing the interface and bound to the library
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library
Adds a library to be loaded. Multiple libraries can be specified using additional calls to this method, and all libraries will be searched to resolve symbols (e.g. functions, variables).- Parameters:
libraryName
- The name or path of library to load.- Returns:
- The
LibraryLoader
instance.
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searchDefault
Add the default library to the search order. This will search all loaded libraries in the current process according to the system's implementation of dlsym(RTLD_DEFAULT).- Returns:
- The
LibraryLoader
instance.
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search
Adds a path to search for libraries. Multiple paths can be specified using multiple calls to this method, and all paths will be searched..- Parameters:
path
- A directory to search.- Returns:
- The
LibraryLoader
instance.
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option
Sets an option when loading libraries.- Parameters:
option
- The option to set.value
- The value for the option.- Returns:
- The
LibraryLoader
instance. - See Also:
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mapper
Adds a type mapper to use when resolving method parameter and result types. Multiple type mappers can be specified by additional calls to this method, and each mapper will be tried in order until one is successful.- Parameters:
typeMapper
- The type mapper to use.- Returns:
- The
LibraryLoader
instance.
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mapper
Adds a type mapper to use when resolving method parameter and result types. Multiple type mappers can be specified by additional calls to this method, and each mapper will be tried in order until one is successful.- Parameters:
typeMapper
- The type mapper to use.- Returns:
- The
LibraryLoader
instance.
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map
public <J> LibraryLoader<T> map(Class<? extends J> javaType, ToNativeConverter<? extends J, ?> toNativeConverter) Adds a custom java type mapping.- Type Parameters:
J
- The Java type.- Parameters:
javaType
- The java type to convert to a native type.toNativeConverter
- AToNativeConverter
that will convert from the java type to a native type.- Returns:
- The
LibraryLoader
instance.
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map
public <J> LibraryLoader<T> map(Class<? extends J> javaType, FromNativeConverter<? extends J, ?> fromNativeConverter) Adds a custom java type mapping.- Type Parameters:
J
- The Java type.- Parameters:
javaType
- The java type to convert to a native type.fromNativeConverter
- AToNativeConverter
that will convert from the native type to a java type.- Returns:
- The
LibraryLoader
instance.
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map
public <J> LibraryLoader<T> map(Class<? extends J> javaType, DataConverter<? extends J, ?> dataConverter) -
mapper
Adds a function mapper to use when resolving symbols in this library. Multiple function mappers can be specified by additional calls to this method, and each mapper will be tried in order, until one is successful.- Parameters:
functionMapper
- The function mapper to use.- Returns:
- The
LibraryLoader
instance.
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map
Adds a function name mapping to use when resolving symbols in this library.- Parameters:
javaName
- The java method name.nativeFunction
- The native library symbol to map the java method name to.- Returns:
- The
LibraryLoader
instance.
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convention
Sets the native function calling convention.This is only needed on windows platforms - unless explicitly specified, all platforms assume
CallingConvention.DEFAULT
as the calling convention.- Parameters:
convention
- The calling convention.- Returns:
- The
LibraryLoader
instance.
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stdcall
Sets the calling convention of the library to the Windows stdcall calling convention- Returns:
- This
LibraryLoader
instance.
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failImmediately
Turns off lazy propagation of load failures. By default,load()
will not fail immediately if any libraries cannot be loaded - instead, it will create an instance of the library interface that re-throws any load errors when invoked. Calling this method will makeload()
throw errors immediately.- Returns:
- This
LibraryLoader
instance.
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load
Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.- Parameters:
libraryName
- The name or path of library to load.- Returns:
- an implementation of the interface provided to
create(Class)
that will call the native methods.
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load
Loads a native library and links the methods defined ininterfaceClass
to native methods in the library.- Returns:
- an implementation of the interface provided to
create(Class)
that will call the native methods.
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loadLibrary
protected abstract T loadLibrary(Class<T> interfaceClass, Collection<String> libraryNames, Collection<String> searchPaths, Map<LibraryOption, Object> options, boolean failImmediately) Implemented by FFI providers to load the actual library.- Parameters:
interfaceClass
- The java class that describes the functions to be mapped.libraryNames
- A list of libraries to load and search for symbols.searchPaths
- The paths to search for libraries to be loaded.options
- The options to apply when loading the library.failImmediately
- whether to fast-fail when the library does not implement the requested functions- Returns:
- an instance of
interfaceClass
that will call the native methods.
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