net.sourceforge.pmd.dcd.graph

Class UsageGraph

java.lang.Object

net.sourceforge.pmd.dcd.graph.UsageGraph

All Implemented Interfaces:

NodeVisitorAcceptor

public class UsageGraph
extends Object
implements NodeVisitorAcceptor

A UsageGraph tracks usage references between Java classes, based upon a parsing of the class files. Once the UsageGraph is built, it may be visited to perform additional post-processing, or usage relationship analysis.

The UsageGraph is composed of ClassNodes. Each ClassNode has various MemberNodes, specifically ConstructorNodes, FieldNodes, and MethodNodes. Each of these MemberNodes keeps track of other MemberNodes which it uses and other MemberNodes which are users of it. In this sense, the graph can navigated bi-directionally across the use relationship between MemberNodes.

Great effort is taken to keep the bookkeeping of the UsageGraph as tight as possible, so that rather large code bases can be analyzed. While nodes can grant access to the underlying Java Reflection APIs (e.g. Class, Constructor, Field, Member), the results are stored using WeakReferences to assist with memory usage.

A class Filter can be specified to limit the set of classes on which usage references will be tracked. This is often done to limit memory usage to interesting classes. For example, the java.util package is very often used, and tracking usages would require a massive bookkeeping effort which has little value.

See Also:

UsageGraphBuilder, ClassNode, MemberNode, ConstructorNode, FieldNode, MethodNode, NodeVisitor, NodeVisitorAcceptor

Field Summary

Fields

Modifier and Type	Field and Description
protected Filter<String>	classFilter

Constructor Summary

Constructors

Constructor and Description
UsageGraph(Filter<String> classFilter)

Method Summary

Methods

Modifier and Type	Method and Description
Object	accept(NodeVisitor visitor, Object data)
ClassNode	defineClass(String className)
MemberNode	defineConstructor(String className, String name, String desc)
FieldNode	defineField(String className, String name, String desc)
MemberNode	defineMethod(String className, String name, String desc)
boolean	isClass(String className)
void	usageField(String className, String name, String desc, MemberNode usingMemberNode)
void	usageMethod(String className, String name, String desc, MemberNode usingMemberNode)

Methods inherited from class java.lang.Object

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

Field Detail

classFilter

protected final Filter<String> classFilter

Constructor Detail

UsageGraph

public UsageGraph(Filter<String> classFilter)

Method Detail

accept

public Object accept(NodeVisitor visitor,
            Object data)

Specified by:

accept in interface NodeVisitorAcceptor

isClass

public boolean isClass(String className)

defineClass

public ClassNode defineClass(String className)

defineField

public FieldNode defineField(String className,
                    String name,
                    String desc)

defineConstructor

public MemberNode defineConstructor(String className,
                           String name,
                           String desc)

defineMethod

public MemberNode defineMethod(String className,
                      String name,
                      String desc)

usageField

public void usageField(String className,
              String name,
              String desc,
              MemberNode usingMemberNode)

usageMethod

public void usageMethod(String className,
               String name,
               String desc,
               MemberNode usingMemberNode)