org.eclipse.jdt.internal.compiler.flow
Class NullInfoRegistry

java.lang.Object
  org.eclipse.jdt.internal.compiler.flow.FlowInfo
      org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo
          org.eclipse.jdt.internal.compiler.flow.NullInfoRegistry

public class NullInfoRegistry
extends UnconditionalFlowInfo

A degenerate form of UnconditionalFlowInfo explicitly meant to capture the effects of null related operations within try blocks. Given the fact that a try block might exit at any time, a null related operation that occurs within such a block mitigates whatever we know about the previous null status of involved variables. NullInfoRegistry handles that by negating upstream definite information that clashes with what a given statement contends about the same variable. It also implements mitigateNullInfo so as to elaborate the flow info presented in input of finally blocks.

Nested Class Summary

Nested classes/interfaces inherited from class org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo

UnconditionalFlowInfo.AssertionFailedException

Field Summary

Fields inherited from class org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo

BitCacheSize, coverageTestFlag, coverageTestId, definiteInits, extra, extraLength, maxFieldCount, nullBit1, nullBit2, nullBit3, nullBit4, potentialInits

Fields inherited from class org.eclipse.jdt.internal.compiler.flow.FlowInfo

DEAD_END, NON_NULL, NULL, NULL_FLAG_MASK, REACHABLE, tagBits, UNKNOWN, UNREACHABLE

Constructor Summary

NullInfoRegistry(UnconditionalFlowInfo upstream)
Make a new null info registry, using an upstream flow info.

Method Summary

NullInfoRegistry	add(NullInfoRegistry other) Add the information held by another NullInfoRegistry instance to this, then return this.
void	markAsComparedEqualToNonNull(LocalVariableBinding local) Record that a local variable got checked to be non null.
void	markAsDefinitelyNonNull(LocalVariableBinding local) Record a local got definitely assigned to a non-null value.
void	markAsDefinitelyNull(LocalVariableBinding local) Record a local got definitely assigned to null.
void	markAsDefinitelyUnknown(LocalVariableBinding local) Mark a local as having been assigned to an unknown value.
UnconditionalFlowInfo	mitigateNullInfoOf(FlowInfo flowInfo) Mitigate the definite and protected info of flowInfo, depending on what this null info registry knows about potential assignments and messages sends involving locals.
java.lang.String	toString()

Methods inherited from class org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo

addInitializationsFrom, addPotentialInitializationsFrom, addPotentialNullInfoFrom, cannotBeDefinitelyNullOrNonNull, cannotBeNull, canOnlyBeNull, copy, discardInitializationInfo, discardNonFieldInitializations, initsWhenFalse, initsWhenTrue, isDefinitelyAssigned, isDefinitelyAssigned, isDefinitelyNonNull, isDefinitelyNull, isDefinitelyUnknown, isPotentiallyAssigned, isPotentiallyAssigned, isPotentiallyNonNull, isPotentiallyNull, isPotentiallyUnknown, isProtectedNonNull, isProtectedNull, markAsComparedEqualToNull, markAsDefinitelyAssigned, markAsDefinitelyAssigned, markAsPotentiallyNull, mergedWith, nullInfoLessUnconditionalCopy, safeInitsWhenTrue, setReachMode, unconditionalCopy, unconditionalFieldLessCopy, unconditionalInits, unconditionalInitsWithoutSideEffect

Methods inherited from class org.eclipse.jdt.internal.compiler.flow.FlowInfo

asNegatedCondition, conditional, initial, mergedOptimizedBranches, reachMode

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NullInfoRegistry

public NullInfoRegistry(UnconditionalFlowInfo upstream)

Make a new null info registry, using an upstream flow info. All definite assignments of the upstream are carried forward, since a try block may exit before its first statement.

Parameters:

upstream - - UnconditionalFlowInfo: the flow info before we enter the try block; only definite assignments are considered; this parameter is not modified by this constructor

Method Detail

add

public NullInfoRegistry add(NullInfoRegistry other)

Add the information held by another NullInfoRegistry instance to this, then return this.

Parameters:

other - - NullInfoRegistry: the information to add to this

Returns:

this, modified to carry the information held by other

markAsComparedEqualToNonNull

public void markAsComparedEqualToNonNull(LocalVariableBinding local)

Description copied from class: FlowInfo

Record that a local variable got checked to be non null.

Overrides:

markAsComparedEqualToNonNull in class UnconditionalFlowInfo

Parameters:

local - the checked local variable

markAsDefinitelyNonNull

public void markAsDefinitelyNonNull(LocalVariableBinding local)

Description copied from class: FlowInfo

Record a local got definitely assigned to a non-null value.

Overrides:

markAsDefinitelyNonNull in class UnconditionalFlowInfo

markAsDefinitelyNull

public void markAsDefinitelyNull(LocalVariableBinding local)

Description copied from class: FlowInfo

Record a local got definitely assigned to null.

Overrides:

markAsDefinitelyNull in class UnconditionalFlowInfo

markAsDefinitelyUnknown

public void markAsDefinitelyUnknown(LocalVariableBinding local)

Description copied from class: UnconditionalFlowInfo

Mark a local as having been assigned to an unknown value.

Overrides:

markAsDefinitelyUnknown in class UnconditionalFlowInfo

Parameters:

local - the local to mark

mitigateNullInfoOf

public UnconditionalFlowInfo mitigateNullInfoOf(FlowInfo flowInfo)

Mitigate the definite and protected info of flowInfo, depending on what this null info registry knows about potential assignments and messages sends involving locals. May return flowInfo unchanged, or a modified, fresh copy of flowInfo.

Parameters:

flowInfo - - FlowInfo: the flow information that this null info registry may mitigate

Returns:

a copy of flowInfo carrying mitigated information, or else flowInfo unchanged

toString

public java.lang.String toString()

Overrides:

toString in class UnconditionalFlowInfo