Package org.codehaus.groovy.ast

Class ClassNode

java.lang.Object
org.codehaus.groovy.ast.ASTNode
org.codehaus.groovy.ast.AnnotatedNode
org.codehaus.groovy.ast.ClassNode
All Implemented Interfaces:
GroovydocHolder<AnnotatedNode>, NodeMetaDataHandler, org.objectweb.asm.Opcodes
Direct Known Subclasses:
CompileUnit.ConstructedOuterNestedClassNode, DecompiledClassNode, InnerClassNode, MixinNode, WideningCategories.LowestUpperBoundClassNode
public class ClassNode
extends AnnotatedNode
implements org.objectweb.asm.Opcodes
Represents a class in the AST.

A ClassNode should be created using the methods in ClassHelper. This ClassNode may be used to represent a class declaration or any other type. This class uses a proxy mechanism allowing to create a class for a plain name at AST creation time. In another phase of the compiler the real ClassNode for the plain name may be found. To avoid the need of exchanging this ClassNode with an instance of the correct ClassNode the correct ClassNode is set as redirect. Most method calls are then redirected to that ClassNode.

There are three types of ClassNodes:

  1. Primary ClassNodes:
    A primary ClassNode is one where we have a source representation which is to be compiled by Groovy and which we have an AST for. The groovy compiler will output one class for each such ClassNode that passes through AsmBytecodeGenerator... not more, not less. That means for example Closures become such ClassNodes too at some point.
  2. ClassNodes create through different sources (typically created from a java.lang.reflect.Class object):
    The compiler will not output classes from these, the methods usually do not contain bodies. These kind of ClassNodes will be used in different checks, but not checks that work on the method bodies. For example if such a ClassNode is a super class to a primary ClassNode, then the abstract method test and others will be done with data based on these. Theoretically it is also possible to mix both (1 and 2) kind of classes in a hierarchy, but this probably works only in the newest Groovy versions. Such ClassNodes normally have to isResolved() returning true without having a redirect.In the Groovy compiler the only version of this, that exists, is a ClassNode created through a Class instance
  3. Labels:
    ClassNodes created through ClassHelper.makeWithoutCaching. They are place holders, its redirect points to the real structure, which can be a label too, but following all redirects it should end with a ClassNode from one of the other two categories. If ResolveVisitor finds such a node, it tries to set the redirects. Any such label created after ResolveVisitor has done its work needs to have a redirect pointing to case 1 or 2. If not the compiler may react strange... this can be considered as a kind of dangling pointer.
Note: the redirect mechanism is only allowed for classes that are not primary ClassNodes. Typically this is done for classes created by name only. The redirect itself can be any type of ClassNode.

To describe generic type signature see getGenericsTypes() and setGenericsTypes(GenericsType[]). These methods are not proxied, they describe the type signature used at the point of declaration or the type signatures provided by the class. If the type signatures provided by the class are needed, then a call to redirect() will help.

See Also:
ClassHelper