edu.umd.cs.findbugs.ba

Class LockSet

public final class LockSet extends Object

Lock counts for values (as produced by ValueNumberAnalysis). A LockSet tells us the lock counts for all values in a method, insofar as we can accurately determine them.

Author: David Hovemeyer

See Also: ValueNumberAnalysis

Field Summary
static int	BOTTOM An invalid lock count resulting from the meet of two different (inconsistent) lock counts.
static int	TOP An uninitialized lock value.

Constructor Summary
	LockSet() Constructor.

Method Summary
void	clear() Clear all entries out of this LockSet.
boolean	containsReturnValue(ValueNumberFactory factory) Determine whether or not this lock set contains any locked values which are method return values.
void	copyFrom(LockSet other) Make this LockSet the same as the given one.
int	getLockCount(int valueNumber) Get the lock count for given lock object.
Collection<ValueNumber>	getLockedValueNumbers(ValueNumberFrame frame)
int	getNumLockedObjects() Get the number of distinct lock values with positive lock counts.
void	intersectWith(LockSet other) Destructively intersect this lock set with another.
boolean	isEmpty() Return whether or not this lock set is empty, meaning that no locks have a positive lock count.
boolean	isTop()
void	meetWith(LockSet other) Meet this LockSet with another LockSet, storing the result in this object.
boolean	sameAs(LockSet other) Return whether or not this LockSet is the same as the one given.
void	setDefaultLockCount(int defaultLockCount) Set the default lock count to return for nonexistent lock entries.
void	setLockCount(int valueNumber, int lockCount) Set the lock count for a lock object.

Field Detail

BOTTOM

public static final int BOTTOM

An invalid lock count resulting from the meet of two different (inconsistent) lock counts.

TOP

public static final int TOP

An uninitialized lock value.

Constructor Detail

LockSet

public LockSet()

Constructor. Creates an empty lock set which returns TOP for nonexistent lock entries.

Method Detail

clear

public void clear()

Clear all entries out of this LockSet.

containsReturnValue

public boolean containsReturnValue(ValueNumberFactory factory)

Determine whether or not this lock set contains any locked values which are method return values.

Parameters: factory the ValueNumberFactory that produced the lock values

copyFrom

public void copyFrom(LockSet other)

Make this LockSet the same as the given one.

Parameters: other the LockSet to copy

getLockCount

public int getLockCount(int valueNumber)

Get the lock count for given lock object.

Parameters: valueNumber value number of the lock object

Returns: the lock count for the lock object

getLockedValueNumbers

public Collection<ValueNumber> getLockedValueNumbers(ValueNumberFrame frame)

Parameters: frame

Returns: a set of the locked value numbers

getNumLockedObjects

public int getNumLockedObjects()

Get the number of distinct lock values with positive lock counts.

intersectWith

public void intersectWith(LockSet other)

Destructively intersect this lock set with another. Note that this is not a dataflow merge: we are interested in finding out which locks are held in both sets, not in the exact lock counts.

Parameters: other the other LockSet