- All Implemented Interfaces:
GuardingDynamicLinker
DynamicLinkerFactory so it is given the chance to link
calls to all objects that no other linker recognized. Specifically, this
linker will:
- if the object is a
record, expose all public accessors of record components as property getters forStandardOperation.GEToperations in theStandardNamespace.PROPERTYnamespace; - expose all public methods of form
setXxx(),getXxx(), andisXxx()as property setters and getters forStandardOperation.SETandStandardOperation.GEToperations in theStandardNamespace.PROPERTYnamespace, except for getters for properties with names already handled by record component getters; - expose all public methods for retrieval for
StandardOperation.GEToperation in theStandardNamespace.METHODnamespace; the methods thus retrieved can then be invoked usingStandardOperation.CALL. - expose all public fields as properties, unless there are getters or setters for the properties of the same name;
- expose elements of native Java arrays,
ListandMapobjects asStandardOperation.GETandStandardOperation.SEToperations in theStandardNamespace.ELEMENTnamespace; - expose removal of elements of
ListandMapobjects asStandardOperation.REMOVEoperation in theStandardNamespace.ELEMENTnamespace; - expose a virtual property named
lengthon Java arrays,CollectionandMapobjects; - expose
StandardOperation.NEWon instances ofStaticClassas calls to constructors, including those static class objects that represent Java arrays (their constructors take a singleintparameter representing the length of the array to create); - expose static methods, fields, and properties of classes in a similar
manner to how instance method, fields, and properties are exposed, on
StaticClassobjects. - expose a virtual property named
staticon instances ofClassto access theirStaticClass.
Overloaded method resolution is performed automatically
for property setters, methods, and constructors. Additionally, manual
overloaded method selection is supported by having a call site specify a name
for a method that contains an explicit signature, e.g.
StandardOperation.GET.withNamespace(METHOD).named("parseInt(String,int)")
You can use non-qualified class names in such signatures regardless of those
classes' packages, they will match any class with the same non-qualified name. You
only have to use a fully qualified class name in case non-qualified class
names would cause selection ambiguity (that is extremely rare). Overloaded
resolution for constructors is not automatic as there is no logical place to
attach that functionality to but if a language wishes to provide this
functionality, it can use getConstructorMethod(Class, String) as a
useful building block for it.
Variable argument invocation is handled for both methods and constructors.
Caller sensitive methods can be linked as long as they
are otherwise public and link requests have call site descriptors carrying
full-strength MethodHandles.Lookup objects and not weakened lookups or the public
lookup.
The behavior for handling missing members can be
customized by passing a MissingMemberHandlerFactory to the
constructor.
The class also exposes various methods for discovery of available
property and method names on classes and class instances, as well as access
to per-class linkers using the getLinkerForClass(Class)
method.
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Constructor Summary
ConstructorsConstructorDescriptionCreates a new beans linker.BeansLinker(MissingMemberHandlerFactory missingMemberHandlerFactory) Creates a new beans linker with the specified factory for creating missing member handlers. -
Method Summary
Modifier and TypeMethodDescriptionstatic ObjectgetConstructorMethod(Class<?> clazz, String signature) Return the dynamic method of constructor of the given class and the given signature.getGuardedInvocation(LinkRequest request, LinkerServices linkerServices) Creates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.getInstanceMethodNames(Class<?> clazz) Returns a set of names of all instance methods of a class.getLinkerForClass(Class<?> clazz) Returns a bean linker for a particular single class.getReadableInstancePropertyNames(Class<?> clazz) Returns a set of names of all readable instance properties of a class.getReadableStaticPropertyNames(Class<?> clazz) Returns a set of names of all readable static properties of a class.getStaticMethodNames(Class<?> clazz) Returns a set of names of all static methods of a class.getWritableInstancePropertyNames(Class<?> clazz) Returns a set of names of all writable instance properties of a class.getWritableStaticPropertyNames(Class<?> clazz) Returns a set of names of all writable static properties of a class.static booleanReturns true if the object is a Java constructor (obtained throughgetConstructorMethod(Class, String)}.static booleanisDynamicMethod(Object obj) Returns true if the object is a Java dynamic method (e.g., one obtained through aGET:METHODoperation on a Java object orStaticClassor throughgetConstructorMethod(Class, String).
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Constructor Details
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BeansLinker
public BeansLinker()Creates a new beans linker. Equivalent toBeansLinker(MissingMemberHandlerFactory)withnullpassed as the missing member handler factory, resulting in the default behavior for linking and evaluating missing members. -
BeansLinker
Creates a new beans linker with the specified factory for creating missing member handlers. The passed factory can be null if the default behavior is adequate. SeeMissingMemberHandlerFactoryfor details.- Parameters:
missingMemberHandlerFactory- a factory for creating handlers for operations on missing members.
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Method Details
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getLinkerForClass
Returns a bean linker for a particular single class. Useful when you need to override or extend the behavior of linking for some classes in your language runtime's linker, but still want to delegate to the default behavior in some cases.- Parameters:
clazz- the class- Returns:
- a bean linker for that class
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isDynamicMethod
Returns true if the object is a Java dynamic method (e.g., one obtained through aGET:METHODoperation on a Java object orStaticClassor throughgetConstructorMethod(Class, String).- Parameters:
obj- the object we want to test for being a Java dynamic method.- Returns:
- true if it is a dynamic method, false otherwise.
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isDynamicConstructor
Returns true if the object is a Java constructor (obtained throughgetConstructorMethod(Class, String)}.- Parameters:
obj- the object we want to test for being a Java constructor.- Returns:
- true if it is a constructor, false otherwise.
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getConstructorMethod
Return the dynamic method of constructor of the given class and the given signature. This method is useful for exposing a functionality for selecting an overloaded constructor based on an explicit signature, as this functionality is not otherwise exposed by Dynalink asStaticClassobjects act as overloaded constructors without explicit signature selection. Example usage would be:getConstructorMethod(java.awt.Color.class, "int, int, int").- Parameters:
clazz- the classsignature- full signature of the constructor. Note how you can use names of primitive types, array names with normal Java notation (e.g."int[]"), and normally you can even use unqualified class names (e.g."String, List"instead of"java.lang.String, java.util.List"as long as they don't cause ambiguity in the specific parameter position.- Returns:
- dynamic method for the constructor or null if no constructor with the specified signature exists.
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getReadableInstancePropertyNames
Returns a set of names of all readable instance properties of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all readable instance properties of a class.
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getWritableInstancePropertyNames
Returns a set of names of all writable instance properties of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all writable instance properties of a class.
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getInstanceMethodNames
Returns a set of names of all instance methods of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all instance methods of a class.
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getReadableStaticPropertyNames
Returns a set of names of all readable static properties of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all readable static properties of a class.
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getWritableStaticPropertyNames
Returns a set of names of all writable static properties of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all writable static properties of a class.
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getStaticMethodNames
Returns a set of names of all static methods of a class.- Parameters:
clazz- the class- Returns:
- a set of names of all static methods of a class.
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getGuardedInvocation
public GuardedInvocation getGuardedInvocation(LinkRequest request, LinkerServices linkerServices) throws Exception Description copied from interface:GuardingDynamicLinkerCreates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.- Specified by:
getGuardedInvocationin interfaceGuardingDynamicLinker- Parameters:
request- the object describing the request for linking a particular invocationlinkerServices- linker services- Returns:
- a guarded invocation with a method handle suitable for the
arguments, as well as a guard condition that if fails should trigger
relinking. Must return null if it can't resolve the invocation. If the
returned invocation is unconditional (which is actually quite rare), the
guard in the return value can be null. The invocation can also have any
number of switch points for asynchronous invalidation of the linkage, as
well as a
Throwablesubclass that describes an expected exception condition that also triggers relinking (often it is faster to rely on an infrequent but expectedClassCastExceptionthan on an always evaluatedinstanceofguard). While the linker must produce an invocation with parameter types matching those in the call site descriptor of the link request, it should not try to match the return type expected at the call site except when it can do it with only the conversions that lose neither precision nor magnitude, seeLinkerServices.asTypeLosslessReturn(MethodHandle, MethodType)for further explanation. - Throws:
Exception- if the operation fails for whatever reason
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