edu.umd.cs.findbugs.ba

Interface ResourceTracker<Resource>

All Known Implementing Classes:

StreamResourceTracker

public interface ResourceTracker<Resource>

A ResourceTracker is used with ResourceValueAnalysis to determine where in a method a certain kind of resource is created, and to model the effect of instructions on the state of that resource.

Author:

David Hovemeyer

See Also:

ResourceValueAnalysis

Method Summary

Methods

Modifier and Type	Method and Description
ResourceValueFrameModelingVisitor	createVisitor(Resource resource, org.apache.bcel.generic.ConstantPoolGen cpg) Create a ResourceValueFrameModelingVisitor to model the effect of instructions on the state of the resource.
boolean	ignoreExceptionEdge(Edge edge, Resource resource, org.apache.bcel.generic.ConstantPoolGen cpg) Determine whether the analysis should ignore given exception edge.
boolean	ignoreImplicitExceptions(Resource resource) Determine whether the analysis should ignore exception edges on which only implicit exceptions are propagated.
boolean	isParamInstance(Resource resource, int slot) Return if the given parameter slot contains the resource instance upon entry to the method.
boolean	isResourceClose(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg, Resource resource, ResourceValueFrame frame) Determine if the given instruction is the site where a resource is closed.
Resource	isResourceCreation(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg) Determine if the given instruction is the site where a resource is created.
boolean	mightCloseResource(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg) Determine if the given instruction is the site where a resource is closed.

Method Detail

isResourceCreation

Resource isResourceCreation(BasicBlock basicBlock,
                          org.apache.bcel.generic.InstructionHandle handle,
                          org.apache.bcel.generic.ConstantPoolGen cpg)
                            throws DataflowAnalysisException

Determine if the given instruction is the site where a resource is created.

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

Returns:

an opaque Resource object if it is a creation site, or null if it is not a creation site

Throws:

DataflowAnalysisException

isResourceClose

boolean isResourceClose(BasicBlock basicBlock,
                      org.apache.bcel.generic.InstructionHandle handle,
                      org.apache.bcel.generic.ConstantPoolGen cpg,
                      Resource resource,
                      ResourceValueFrame frame)
                        throws DataflowAnalysisException

Determine if the given instruction is the site where a resource is closed.

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

resource - the resource, as returned by isResourceCreation()

frame - the ResourceValueFrame representing the stack prior to executing the instruction

Returns:

true if the resource is closed here, false otherwise

Throws:

DataflowAnalysisException

mightCloseResource

boolean mightCloseResource(BasicBlock basicBlock,
                         org.apache.bcel.generic.InstructionHandle handle,
                         org.apache.bcel.generic.ConstantPoolGen cpg)
                           throws DataflowAnalysisException

Determine if the given instruction is the site where a resource is closed.

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

Returns:

true if the resource is closed here, false otherwise

Throws:

DataflowAnalysisException

createVisitor

ResourceValueFrameModelingVisitor createVisitor(Resource resource,
                                              org.apache.bcel.generic.ConstantPoolGen cpg)

Create a ResourceValueFrameModelingVisitor to model the effect of instructions on the state of the resource.

Parameters:

resource - the resource we are tracking

cpg - the ConstantPoolGen of the method

Returns:

a ResourceValueFrameModelingVisitor

ignoreImplicitExceptions

boolean ignoreImplicitExceptions(Resource resource)

Determine whether the analysis should ignore exception edges on which only implicit exceptions are propagated. This allows different resource types to be tracked with varying precision. For example, we might want to ignore implicit exceptions for stream objects, but treat them as significant for database resources.

Parameters:

resource - the resource being tracked

Returns:

true if implicit exceptions are significant, false if they should be ignore

ignoreExceptionEdge

boolean ignoreExceptionEdge(Edge edge,
                          Resource resource,
                          org.apache.bcel.generic.ConstantPoolGen cpg)

Determine whether the analysis should ignore given exception edge. This allows the analysis to customize which kinds of exceptions are significant.

Parameters:

edge - the exception edge

resource - the resource

cpg - the ConstantPoolGen

Returns:

true if exception edge should be ignored, false if it should be considered

isParamInstance

boolean isParamInstance(Resource resource,
                      int slot)

Return if the given parameter slot contains the resource instance upon entry to the method. This is for resources passed as parameters.

Parameters:

resource - the resource

slot - the local variable slot

Returns:

true if the slot contains the resource instance, false otherwise