Package org.codehaus.groovy.transform

Class SingletonASTStubber

java.lang.Object

org.codehaus.groovy.transform.AbstractASTTransformation

org.codehaus.groovy.transform.SingletonASTStubber

All Implemented Interfaces:

ASTTransformation, ErrorCollecting

public class SingletonASTStubber
extends AbstractASTTransformation

Joint-compilation stubber for Singleton. Emits the public static getInstance() method (or getXxx() for a custom property name) so Java consumers can call MyClass.getInstance() against the joint-compilation stub.

The placeholder body returns null; the full SingletonASTTransformation at CANONICALIZATION recognises the stubber metadata and replaces the body with the real implementation (which dereferences the singleton field, optionally with double-checked locking when lazy = true).

The corresponding singleton field is intentionally not emitted from the stubber. For the default lazy = false configuration the runtime field is public static final and Java callers could read it directly; emitting it here would risk a duplicate-add at CANONICALIZATION, and the getInstance() accessor is the canonical Java idiom. Adding the field could be a follow-up if the spike's experience suggests Java consumers commonly want field-level access.

Since:

6.0.0

Field Summary

Fields inherited from class org.codehaus.groovy.transform.AbstractASTTransformation

RETENTION_CLASSNODE, sourceUnit

Constructor Summary

Constructors

Constructor	Description
SingletonASTStubber()

Method Summary

Modifier and Type	Method	Description
void	visit(ASTNode[] nodes, SourceUnit source)	The method is invoked when an AST Transformation is active.

Methods inherited from class org.codehaus.groovy.transform.AbstractASTTransformation

addError, checkIncludeExcludeUndefinedAware, checkIncludeExcludeUndefinedAware, checkNotInterface, checkPropertyList, checkPropertyList, checkPropertyList, copyAnnotatedNodeAnnotations, copyAnnotatedNodeAnnotations, deemedInternal, deemedInternalName, getAnnotationName, getMemberClassList, getMemberClassValue, getMemberClassValue, getMemberIntValue, getMemberStringList, getMemberStringValue, getMemberStringValue, getMemberValue, hasAnnotation, init, markAsInternal, memberHasValue, shouldSkip, shouldSkip, shouldSkip, shouldSkipOnDescriptorUndefinedAware, shouldSkipUndefinedAware, shouldSkipUndefinedAware, shouldSkipUndefinedAware, tokenize

Methods inherited from class java.lang.Object

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

Constructor Details

SingletonASTStubber

public SingletonASTStubber()

Method Details

visit

public void visit(ASTNode[] nodes,
 SourceUnit source)

Description copied from interface: ASTTransformation

The method is invoked when an AST Transformation is active. For local transformations, it is invoked once each time the local annotation is encountered. For global transformations, it is invoked once for every source unit, which is typically a source file.

Parameters:

nodes - The ASTnodes when the call was triggered. Element 0 is the AnnotationNode that triggered this annotation to be activated. Element 1 is the AnnotatedNode decorated, such as a MethodNode or ClassNode. For global transformations it is usually safe to ignore this parameter.

source - The source unit being compiled. The source unit may contain several classes. For global transformations, information about the AST can be retrieved from this object.