Class UsageGraph

  extended by net.sourceforge.pmd.dcd.graph.UsageGraph
All Implemented Interfaces:

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
protected  Filter<String> classFilter
Constructor Summary
UsageGraph(Filter<String> classFilter)
Method Summary
 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


protected final Filter<String> classFilter
Constructor Detail


public UsageGraph(Filter<String> classFilter)
Method Detail


public Object accept(NodeVisitor visitor,
                     Object data)
Specified by:
accept in interface NodeVisitorAcceptor


public boolean isClass(String className)


public ClassNode defineClass(String className)


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


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


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


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


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

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