Class Library

java.lang.Object

com.oracle.truffle.api.nodes.Node

com.oracle.truffle.api.library.Library

All Implemented Interfaces:

NodeInterface, Cloneable

Direct Known Subclasses:

DynamicDispatchLibrary, DynamicObjectLibrary, InteropLibrary, NodeLibrary, ReflectionLibrary

public abstract class Library
extends Node

Base class for all Truffle library specifications. Required base class for classes annotated with GenerateLibrary. Implementations for the abstract methods specified in this classes are not supposed to be implemented manually.

Since:

19.0

See Also:

• GenerateLibrary

Nested Class Summary

Nested classes/interfaces inherited from class Node

Node.Child, Node.Children

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Library()	Default constructor for sub-classes.

Method Summary

Modifier and Type	Method	Description
abstract boolean	accepts(Object receiver)	Returns true if this library instance supports sending messages with the given receiver.

Methods inherited from class Node

accept, adoptChildren, atomic, atomic, copy, deepCopy, getChildren, getCost, getDebugProperties, getDescription, getEncapsulatingSourceSection, getLock, getParent, getRootNode, getSourceSection, insert, insert, isAdoptable, isSafelyReplaceableBy, notifyInserted, onReplace, replace, replace, reportPolymorphicSpecialize, reportReplace, toString

Methods inherited from class Object

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

Constructor Details

Library

protected Library()

Default constructor for sub-classes. Libraries always have a no-arg protected constructor.

Since:

19.0

Method Details

accepts

public abstract boolean accepts(Object receiver)

Returns true if this library instance supports sending messages with the given receiver. If accepts returns false and a library message is sent anyway then an AssertionError is thrown if assertions are enabled (-ea). Otherwise a NullPointerException or ClassCastException may be thrown by the method.

A library that was created using a receiver value i.e. a LibraryFactory.create(Object) only guarantees to accept the value it was constructed with. For other values, the method may return false. Such libraries need to check for acceptance before calling a library method with a receiver. If receiver values are not accepted then a new library needs to be created or fetched. Dispatched versions of libraries always return true for any value as they take care of dispatching to any receiver type.

It is not necessary to call accepts manually for most use cases. Instead the CachedLibrary should be used instead. For slow-paths the internally dispatched versions of the uncached library should be used.

The accepts message may be exported by receiver types. When exported it can only be further restricted in addition to the default accepts implementation.

Since:

19.0

See Also:

• for ways how to dispatch libraries.