Class Lookup

java.lang.Object

jdk.dynalink.linker.support.Lookup

public final class Lookup
extends Object

A wrapper around MethodHandles.Lookup that masks checked exceptions. It is useful in those cases when you're looking up methods within your own codebase (therefore it is an error if they are not present).

Since:

9

Field Summary

Fields

Modifier and Type	Field	Description
static final Lookup	PUBLIC	A canonical Lookup object that wraps MethodHandles.publicLookup().

Constructor Summary

Constructors

Constructor	Description
Lookup(MethodHandles.Lookup lookup)	Creates a new instance, bound to an instance of MethodHandles.Lookup.

Method Summary

Modifier and Type	Method	Description
MethodHandle	findGetter(Class<?> refc, String name, Class<?> type)	Performs a MethodHandles.Lookup.findGetter(Class, String, Class), converting any encountered IllegalAccessException into an IllegalAccessError and NoSuchFieldException into a NoSuchFieldError.
static MethodHandle	findOwnSpecial(MethodHandles.Lookup lookup, String name, Class<?> rtype, Class<?>... ptypes)	Given a lookup, finds using findSpecial(Class, String, MethodType) a method on that lookup's class.
MethodHandle	findOwnSpecial(String name, Class<?> rtype, Class<?>... ptypes)	Finds using findSpecial(Class, String, MethodType) a method on that lookup's class.
static MethodHandle	findOwnStatic(MethodHandles.Lookup lookup, String name, Class<?> rtype, Class<?>... ptypes)	Given a lookup, finds using findStatic(Class, String, MethodType) a method on that lookup's class.
MethodHandle	findOwnStatic(String name, Class<?> rtype, Class<?>... ptypes)	Finds using findStatic(Class, String, MethodType) a method on that lookup's class.
MethodHandle	findSpecial(Class<?> declaringClass, String name, MethodType type)	Performs a MethodHandles.Lookup.findSpecial(Class, String, MethodType, Class) on the underlying lookup.
MethodHandle	findStatic(Class<?> declaringClass, String name, MethodType type)	Performs a MethodHandles.Lookup.findStatic(Class, String, MethodType) on the underlying lookup.
MethodHandle	findVirtual(Class<?> declaringClass, String name, MethodType type)	Performs a MethodHandles.Lookup.findVirtual(Class, String, MethodType) on the underlying lookup.
static MethodHandle	unreflect(MethodHandles.Lookup lookup, Method m)	Performs a MethodHandles.Lookup.unreflect(Method), converting any encountered IllegalAccessException into an IllegalAccessError.
MethodHandle	unreflect(Method m)	Performs a MethodHandles.Lookup.unreflect(Method), converting any encountered IllegalAccessException into an IllegalAccessError.
static MethodHandle	unreflectConstructor(MethodHandles.Lookup lookup, Constructor<?> c)	Performs a MethodHandles.Lookup.unreflectConstructor(Constructor), converting any encountered IllegalAccessException into an IllegalAccessError.
MethodHandle	unreflectConstructor(Constructor<?> c)	Performs a MethodHandles.Lookup.unreflectConstructor(Constructor), converting any encountered IllegalAccessException into an IllegalAccessError.
MethodHandle	unreflectGetter(Field f)	Performs a MethodHandles.Lookup.unreflectGetter(Field), converting any encountered IllegalAccessException into an IllegalAccessError.
MethodHandle	unreflectSetter(Field f)	Performs a MethodHandles.Lookup.unreflectSetter(Field), converting any encountered IllegalAccessException into an IllegalAccessError.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Creates and returns a copy of this object.
boolean	equals(Object obj)	Indicates whether some other object is "equal to" this one.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
final Class<?>	getClass()	Returns the runtime class of this Object.
int	hashCode()	Returns a hash code value for this object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
String	toString()	Returns a string representation of the object.
final void	wait()	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
final void	wait(long timeoutMillis)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
final void	wait(long timeoutMillis, int nanos)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Field Details

PUBLIC

public static final Lookup PUBLIC

A canonical Lookup object that wraps MethodHandles.publicLookup().

Constructor Details

Lookup

public Lookup(MethodHandles.Lookup lookup)

Creates a new instance, bound to an instance of MethodHandles.Lookup.

Parameters:

lookup - the MethodHandles.Lookup it delegates to.

Method Details

unreflect

public MethodHandle unreflect(Method m)

Performs a MethodHandles.Lookup.unreflect(Method), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

m - the method to unreflect

Returns:

the unreflected method handle.

Throws:

IllegalAccessError - if the method is inaccessible.

unreflect

public static MethodHandle unreflect(MethodHandles.Lookup lookup,
 Method m)

Performs a MethodHandles.Lookup.unreflect(Method), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

lookup - the lookup used to unreflect

m - the method to unreflect

Returns:

the unreflected method handle.

Throws:

IllegalAccessError - if the method is inaccessible.

unreflectGetter

public MethodHandle unreflectGetter(Field f)

Performs a MethodHandles.Lookup.unreflectGetter(Field), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

f - the field for which a getter is unreflected

Returns:

the unreflected field getter handle.

Throws:

IllegalAccessError - if the getter is inaccessible.

findGetter

public MethodHandle findGetter(Class<?> refc,
 String name,
 Class<?> type)

Performs a MethodHandles.Lookup.findGetter(Class, String, Class), converting any encountered IllegalAccessException into an IllegalAccessError and NoSuchFieldException into a NoSuchFieldError.

Parameters:

refc - the class declaring the field

name - the name of the field

type - the type of the field

Returns:

the unreflected field getter handle.

Throws:

IllegalAccessError - if the field is inaccessible.

NoSuchFieldError - if the field does not exist.

unreflectSetter

public MethodHandle unreflectSetter(Field f)

Performs a MethodHandles.Lookup.unreflectSetter(Field), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

f - the field for which a setter is unreflected

Returns:

the unreflected field setter handle.

Throws:

IllegalAccessError - if the field is inaccessible.

NoSuchFieldError - if the field does not exist.

unreflectConstructor

public MethodHandle unreflectConstructor(Constructor<?> c)

Performs a MethodHandles.Lookup.unreflectConstructor(Constructor), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

c - the constructor to unreflect

Returns:

the unreflected constructor handle.

Throws:

IllegalAccessError - if the constructor is inaccessible.

unreflectConstructor

public static MethodHandle unreflectConstructor(MethodHandles.Lookup lookup,
 Constructor<?> c)

Performs a MethodHandles.Lookup.unreflectConstructor(Constructor), converting any encountered IllegalAccessException into an IllegalAccessError.

Parameters:

lookup - the lookup used to unreflect

c - the constructor to unreflect

Returns:

the unreflected constructor handle.

Throws:

IllegalAccessError - if the constructor is inaccessible.

findSpecial

public MethodHandle findSpecial(Class<?> declaringClass,
 String name,
 MethodType type)

Performs a MethodHandles.Lookup.findSpecial(Class, String, MethodType, Class) on the underlying lookup. Converts any encountered IllegalAccessException into an IllegalAccessError and NoSuchMethodException into a NoSuchMethodError.

Parameters:

declaringClass - class declaring the method

name - the name of the method

type - the type of the method

Returns:

a method handle for the method

Throws:

IllegalAccessError - if the method is inaccessible.

NoSuchMethodError - if the method does not exist.

findStatic

public MethodHandle findStatic(Class<?> declaringClass,
 String name,
 MethodType type)

Performs a MethodHandles.Lookup.findStatic(Class, String, MethodType) on the underlying lookup. Converts any encountered IllegalAccessException into an IllegalAccessError and NoSuchMethodException into a NoSuchMethodError.

Parameters:

declaringClass - class declaring the method

name - the name of the method

type - the type of the method

Returns:

a method handle for the method

Throws:

IllegalAccessError - if the method is inaccessible.

NoSuchMethodError - if the method does not exist.

findVirtual

public MethodHandle findVirtual(Class<?> declaringClass,
 String name,
 MethodType type)

Performs a MethodHandles.Lookup.findVirtual(Class, String, MethodType) on the underlying lookup. Converts any encountered IllegalAccessException into an IllegalAccessError and NoSuchMethodException into a NoSuchMethodError.

Parameters:

declaringClass - class declaring the method

name - the name of the method

type - the type of the method

Returns:

a method handle for the method

Throws:

IllegalAccessError - if the method is inaccessible.

NoSuchMethodError - if the method does not exist.

findOwnSpecial

public static MethodHandle findOwnSpecial(MethodHandles.Lookup lookup,
 String name,
 Class<?> rtype,
 Class<?>... ptypes)

Given a lookup, finds using findSpecial(Class, String, MethodType) a method on that lookup's class. Useful in classes' code for convenient linking to their own privates.

Parameters:

lookup - the lookup for the class

name - the name of the method

rtype - the return type of the method

ptypes - the parameter types of the method

Returns:

the method handle for the method

findOwnSpecial

public MethodHandle findOwnSpecial(String name,
 Class<?> rtype,
 Class<?>... ptypes)

Finds using findSpecial(Class, String, MethodType) a method on that lookup's class. Useful in classes' code for convenient linking to their own privates. It's also more convenient than findSpecial in that you can just list the parameter types, and don't have to specify lookup class.

Parameters:

name - the name of the method

rtype - the return type of the method

ptypes - the parameter types of the method

Returns:

the method handle for the method

findOwnStatic

public static MethodHandle findOwnStatic(MethodHandles.Lookup lookup,
 String name,
 Class<?> rtype,
 Class<?>... ptypes)

Given a lookup, finds using findStatic(Class, String, MethodType) a method on that lookup's class. Useful in classes' code for convenient linking to their own privates. It's easier to use than findStatic in that you can just list the parameter types, and don't have to specify lookup class.

Parameters:

lookup - the lookup for the class

name - the name of the method

rtype - the return type of the method

ptypes - the parameter types of the method

Returns:

the method handle for the method

findOwnStatic

public MethodHandle findOwnStatic(String name,
 Class<?> rtype,
 Class<?>... ptypes)

Finds using findStatic(Class, String, MethodType) a method on that lookup's class. Useful in classes' code for convenient linking to their own privates. It's easier to use than findStatic in that you can just list the parameter types, and don't have to specify lookup class.

Parameters:

name - the name of the method

rtype - the return type of the method

ptypes - the parameter types of the method

Returns:

the method handle for the method