NullPointerAnalysis

java.lang.Object
- soot.toolkits.scalar.AbstractFlowAnalysis<N,A>
- - soot.toolkits.scalar.BranchedFlowAnalysis<soot.Unit,A>
  - - soot.toolkits.scalar.ForwardBranchedFlowAnalysis
    - - soot.jimple.toolkits.annotation.nullcheck.BranchedRefVarsAnalysis
      - ptolemy.copernicus.kernel.NullPointerAnalysis

```
public class NullPointerAnalysis
extends soot.jimple.toolkits.annotation.nullcheck.BranchedRefVarsAnalysis
```
An analysis that can determine, at any point in the code, if a local variable points to null. This is just a nice wrapper class for soot's BranchedRefVarsAnalysis.

Since:

Ptolemy II 4.0

Version:

$Id$

Author:

Steve Neuendorffer

Pt.AcceptedRating:

Red (cxh)

Pt.ProposedRating:

Red (cxh)

Field Summary
- Fields inherited from class soot.jimple.toolkits.annotation.nullcheck.BranchedRefVarsAnalysis
  emptySet, fullSet, kBottom, kNonNull, kNull, kTop, refTypeInstFieldBases, refTypeInstFields, refTypeLocals, refTypeStaticFields, refTypeValues, tempFlowSet, unitToAnalyzedChecksSet, unitToArrayRefChecksSet, unitToGenerateSet, unitToInstanceFieldRefChecksSet, unitToInstanceInvokeExprChecksSet, unitToLengthExprChecksSet, unitToPreserveSet
- Fields inherited from class soot.toolkits.scalar.BranchedFlowAnalysis
  unitToAfterBranchFlow, unitToAfterFallFlow
- Fields inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
  filterUnitToBeforeFlow, graph, unitToBeforeFlow

Constructor Summary

Constructors
Constructor Description

NullPointerAnalysis(soot.toolkits.graph.UnitGraph g)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`isAlwaysNullBefore(soot.Local local, soot.Unit unit)`	Return the set of other fields and locals that must reference the same object as the given field, at a point before the given unit.
`boolean`	`isNeverNullBefore(soot.Local local, soot.Unit unit)`	Return the set of other fields and locals that must reference the same object as the given local, at a point before the given unit.

Methods inherited from class soot.jimple.toolkits.annotation.nullcheck.BranchedRefVarsAnalysis
anyRefInfo, copy, entryInitialFlow, flowThrough, getEquivalentValue, getKRefIntPair, isAlwaysNonNull, merge, newInitialFlow, refInfo, refInfo, treatTrapHandlersAsEntries

Methods inherited from class soot.toolkits.scalar.ForwardBranchedFlowAnalysis
doAnalysis, isForward

Methods inherited from class soot.toolkits.scalar.BranchedFlowAnalysis
getBranchFlowAfter, getFallFlowAfter, getFlowBefore

Methods inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
merge, mergeInto

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - NullPointerAnalysis
```
public NullPointerAnalysis(soot.toolkits.graph.UnitGraph g)
```
- Method Detail
  - isAlwaysNullBefore
```
public boolean isAlwaysNullBefore(soot.Local local,
                                  soot.Unit unit)
```
    Return the set of other fields and locals that must reference the same object as the given field, at a point before the given unit.
  - isNeverNullBefore
```
public boolean isNeverNullBefore(soot.Local local,
                                 soot.Unit unit)
```
    Return the set of other fields and locals that must reference the same object as the given local, at a point before the given unit.