java.lang.Object
- edu.umd.cs.findbugs.ba.npe.IsNullValue

All Implemented Interfaces:

Debug, IsNullValueAnalysisFeatures
```
public class IsNullValue
extends java.lang.Object
implements IsNullValueAnalysisFeatures, Debug
```
A class to abstractly represent values in stack slots, indicating whether thoses values can be null, non-null, null on some incoming path, or unknown.

Author:

David Hovemeyer

See Also:

IsNullValueFrame, IsNullValueAnalysis

Field Summary
- Fields inherited from interface edu.umd.cs.findbugs.ba.Debug
  VERIFY_INTEGRITY
- Fields inherited from interface edu.umd.cs.findbugs.ba.npe.IsNullValueAnalysisFeatures
  NCP_EXTRA_BRANCH, NO_SPLIT_DOWNGRADE_NSP, NO_SWITCH_DEFAULT_AS_EXCEPTION, UNKNOWN_VALUES_ARE_NSP, USE_TYPE_QUALIFIERS

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static IsNullValue`	`checkedNonNullValue()`	Get the instance representing a value known to be non-null because it was compared against null value, or because we saw the object creation.
`static IsNullValue`	`checkedNullValue()`	Get the instance representing a value known to be null because it was compared against null value, or because we saw that it was assigned the null constant.
`IsNullValue`	`downgradeOnControlSplit()`	Control split: move given value down in the lattice if it is a conditionally-null value.
`boolean`	`equals(java.lang.Object o)`
`Location`	`getLocationOfKaBoom()`
`int`	`hashCode()`
`boolean`	`isChecked()`	Is this value known because of an explicit null check?
`boolean`	`isDefinitelyNotNull()`	Is this value definitely not null?
`boolean`	`isDefinitelyNull()`	Is this value definitely null?
`boolean`	`isException()`	Was this value propagated on an exception path?
`boolean`	`isFieldValue()`
`boolean`	`isNullOnComplicatedPath()`	Is this value null on a complicated path?
`boolean`	`isNullOnComplicatedPath2()`	Is this value null on a complicated path?
`boolean`	`isNullOnComplicatedPath23()`	Is this value null on a complicated path?
`boolean`	`isNullOnSomePath()`	Is this value null on some path?
`boolean`	`isParamValue()`	Was this value marked as a possibly null parameter?
`boolean`	`isReadlineValue()`
`boolean`	`isReturnValue()`	Was this value marked as a possibly null return value?
`IsNullValue`	`markInformationAsComingFromFieldValue(XField field)`	Convert to a value known because it was returned from a method in a method property database.
`IsNullValue`	`markInformationAsComingFromReturnValueOfMethod(XMethod methodInvoked)`	Convert to a value known because it was returned from a method in a method property database.
`static IsNullValue`	`merge(IsNullValue a, IsNullValue b)`	Merge two values.
`boolean`	`mightBeNull()`	Return true if this value is either definitely null, or might be null on a simple path.
`static IsNullValue`	`noKaboomNonNullValue(Location ins)`	Get the instance representing a value known to be non-null because a NPE would have occurred if it were null.
`static IsNullValue`	`nonNullValue()`	Get the instance representing values that are definitely not null.
`static IsNullValue`	`nonReportingNotNullValue()`	Get non-reporting non-null value.
`static IsNullValue`	`nullOnComplexPathValue()`	Get null on complex path value.
`static IsNullValue`	`nullOnComplexPathValue3()`	Like "null on complex path" except that there are at least three branches between the explicit null value and the current location.
`static IsNullValue`	`nullOnSimplePathValue()`	Get the instance representing values that are definitely null on some simple (no branches) incoming path.
`static IsNullValue`	`nullValue()`	Get the instance representing values that are definitely null.
`static IsNullValue`	`parameterMarkedAsMightBeNull(XMethodParameter mp)`	Get instance representing a parameter marked as MightBeNull
`static IsNullValue`	`parameterMarkedAsNonnull(XMethodParameter mp)`	Get instance representing a parameter marked as Nonnull
`static IsNullValue`	`pathSensitiveNonNullValue()`	Get non-null value resulting from comparison to explicit null.
`static IsNullValue`	`pathSensitiveNullValue()`	Get null value resulting from comparison to explicit null.
`IsNullValue`	`toExceptionValue()`	Convert to an exception path value.
`java.lang.String`	`toString()`
`boolean`	`wouldHaveBeenAKaboom()`	Is this value known to be non null because a NPE would have occurred otherwise?

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

- Method Detail
  - equals
```
public boolean equals(java.lang.Object o)
```
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - isException
```
public boolean isException()
```
    Was this value propagated on an exception path?
  - isReturnValue
```
public boolean isReturnValue()
```
    Was this value marked as a possibly null return value?
  - isReadlineValue
```
public boolean isReadlineValue()
```
  - isFieldValue
```
public boolean isFieldValue()
```
  - isParamValue
```
public boolean isParamValue()
```
    Was this value marked as a possibly null parameter?
  - isChecked
```
public boolean isChecked()
```
    Is this value known because of an explicit null check?
  - wouldHaveBeenAKaboom
```
public boolean wouldHaveBeenAKaboom()
```
    Is this value known to be non null because a NPE would have occurred otherwise?
  - toExceptionValue
```
public IsNullValue toExceptionValue()
```
    Convert to an exception path value.
  - markInformationAsComingFromReturnValueOfMethod
```
public IsNullValue markInformationAsComingFromReturnValueOfMethod(XMethod methodInvoked)
```
    Convert to a value known because it was returned from a method in a method property database.
    
    Parameters:
    
    methodInvoked - TODO
  - markInformationAsComingFromFieldValue
```
public IsNullValue markInformationAsComingFromFieldValue(XField field)
```
    Convert to a value known because it was returned from a method in a method property database.
    
    Parameters:
    
    field - TODO
  - nullValue
```
public static IsNullValue nullValue()
```
    Get the instance representing values that are definitely null.
  - checkedNullValue
```
public static IsNullValue checkedNullValue()
```
    Get the instance representing a value known to be null because it was compared against null value, or because we saw that it was assigned the null constant.
  - nonNullValue
```
public static IsNullValue nonNullValue()
```
    Get the instance representing values that are definitely not null.
  - checkedNonNullValue
```
public static IsNullValue checkedNonNullValue()
```
    Get the instance representing a value known to be non-null because it was compared against null value, or because we saw the object creation.
  - noKaboomNonNullValue
```
public static IsNullValue noKaboomNonNullValue(@Nonnull
                                               Location ins)
```
    Get the instance representing a value known to be non-null because a NPE would have occurred if it were null.
  - nullOnSimplePathValue
```
public static IsNullValue nullOnSimplePathValue()
```
    Get the instance representing values that are definitely null on some simple (no branches) incoming path.
  - parameterMarkedAsMightBeNull
```
public static IsNullValue parameterMarkedAsMightBeNull(XMethodParameter mp)
```
    Get instance representing a parameter marked as MightBeNull
  - parameterMarkedAsNonnull
```
public static IsNullValue parameterMarkedAsNonnull(XMethodParameter mp)
```
    Get instance representing a parameter marked as Nonnull
  - nonReportingNotNullValue
```
public static IsNullValue nonReportingNotNullValue()
```
    Get non-reporting non-null value. This is what we use for unknown values.
  - nullOnComplexPathValue
```
public static IsNullValue nullOnComplexPathValue()
```
    Get null on complex path value. This is like null on simple path value, but there are at least two branches between the explicit null value and the current location. If the conditions are correlated, then the path on which the value is null may be infeasible.
  - nullOnComplexPathValue3
```
public static IsNullValue nullOnComplexPathValue3()
```
    Like "null on complex path" except that there are at least three branches between the explicit null value and the current location.
  - pathSensitiveNullValue
```
public static IsNullValue pathSensitiveNullValue()
```
    Get null value resulting from comparison to explicit null.
  - pathSensitiveNonNullValue
```
public static IsNullValue pathSensitiveNonNullValue()
```
    Get non-null value resulting from comparison to explicit null.
  - merge
```
public static IsNullValue merge(IsNullValue a,
                                IsNullValue b)
```
    Merge two values.
  - isDefinitelyNull
```
public boolean isDefinitelyNull()
```
    Is this value definitely null?
  - isNullOnSomePath
```
public boolean isNullOnSomePath()
```
    Is this value null on some path?
  - isNullOnComplicatedPath
```
public boolean isNullOnComplicatedPath()
```
    Is this value null on a complicated path?
  - isNullOnComplicatedPath23
```
public boolean isNullOnComplicatedPath23()
```
    Is this value null on a complicated path?
  - isNullOnComplicatedPath2
```
public boolean isNullOnComplicatedPath2()
```
    Is this value null on a complicated path?
  - mightBeNull
```
public boolean mightBeNull()
```
    Return true if this value is either definitely null, or might be null on a simple path.
    
    Returns:
    
    true if this value is either definitely null, or might be null on a simple path, false otherwise
  - isDefinitelyNotNull
```
public boolean isDefinitelyNotNull()
```
    Is this value definitely not null?
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - getLocationOfKaBoom
```
public Location getLocationOfKaBoom()
```
  - downgradeOnControlSplit
```
public IsNullValue downgradeOnControlSplit()
```
    Control split: move given value down in the lattice if it is a conditionally-null value.
    
    Returns:
    
    another value (equal or further down in the lattice)

Class IsNullValue

Field Summary

Fields inherited from interface edu.umd.cs.findbugs.ba.Debug

Fields inherited from interface edu.umd.cs.findbugs.ba.npe.IsNullValueAnalysisFeatures

Method Summary

Methods inherited from class java.lang.Object

Method Detail

equals

hashCode

isException

isReturnValue

isReadlineValue

isFieldValue

isParamValue

isChecked

wouldHaveBeenAKaboom

toExceptionValue

markInformationAsComingFromReturnValueOfMethod

markInformationAsComingFromFieldValue

nullValue

checkedNullValue

nonNullValue

checkedNonNullValue

noKaboomNonNullValue

nullOnSimplePathValue

parameterMarkedAsMightBeNull

parameterMarkedAsNonnull

nonReportingNotNullValue

nullOnComplexPathValue

nullOnComplexPathValue3

pathSensitiveNullValue

pathSensitiveNonNullValue

merge

isDefinitelyNull

isNullOnSomePath

isNullOnComplicatedPath

isNullOnComplicatedPath23

isNullOnComplicatedPath2

mightBeNull

isDefinitelyNotNull

toString

getLocationOfKaBoom

downgradeOnControlSplit