edu.umd.cs.findbugs.ba

Class BlockType

java.lang.Object

java.util.BitSet

edu.umd.cs.findbugs.ba.BlockType

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class BlockType
extends java.util.BitSet

Dataflow value representing the current nesting of catch and finally blocks. We assume that any catch block with a non-empty catch type is a user catch block, and any catch block with an empty catch type (i.e., catch all exceptions) is a finally block. This assumption isn't quite accurate, but it seems to be a reasonable first approximation.

If valid (isValid() returns true), a BlockType value is a stack of elements, which are either CATCH or FINALLY values. Call getDepth() to get the current nesting depth. Call get(int n) to get the nth stack item. Call getTopValue() to get the current top of the stack.

If invalid (isValid() returns false), a BlockType value is either top or bottom. These are the special values at the top and bottom of the dataflow lattice.

The dataflow lattice is effectively finite-height because real Java methods are guaranteed to have a finite catch and finally block nesting level.

Author:

David Hovemeyer

See Also:

BlockTypeAnalysis, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	CATCH
static boolean	FINALLY

Method Summary

Methods

Modifier and Type	Method and Description
void	copyFrom(BlockType other) Make this object an exact duplicate of given object.
boolean	equals(java.lang.Object obj)
int	getDepth() Get the current nesting depth.
boolean	getTopValue() Get the top value on the catch and finally block nesting stack.
int	hashCode()
boolean	isBottom() Return whether or not this is the special "bottom" dataflow value.
boolean	isNormal() Return whether or not this value represents "normal" control-flow.
boolean	isTop() Return whether or not this is the special "top" dataflow value.
boolean	isValid() Return whether or not this value is valid, meaning it contains a valid representation of the nesting of catch and finally blocks.
void	mergeWith(BlockType other) Merge other dataflow value into this value.
void	pushCatch() Enter a catch block.
void	pushFinally() Enter a finally block.
boolean	sameAs(BlockType other) Return whether or not this object is identical to the one given.
void	setBottom() Make this the special "bottom" dataflow value.
void	setNormal() Make this value represent "normal" control flow.
void	setTop() Make this the special "top" dataflow value.
java.lang.String	toString()

Methods inherited from class java.util.BitSet

and, andNot, cardinality, clear, clear, clear, clone, flip, flip, get, get, intersects, isEmpty, length, nextClearBit, nextSetBit, or, previousClearBit, previousSetBit, set, set, set, set, size, toByteArray, toLongArray, valueOf, valueOf, valueOf, valueOf, xor

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

CATCH

public static final boolean CATCH

See Also:

Constant Field Values

FINALLY

public static final boolean FINALLY

See Also:

Constant Field Values

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class java.util.BitSet

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.util.BitSet

isValid

public boolean isValid()

Return whether or not this value is valid, meaning it contains a valid representation of the nesting of catch and finally blocks.

getDepth

public int getDepth()

Get the current nesting depth. The value must be valid.

getTopValue

public boolean getTopValue()

Get the top value on the catch and finally block nesting stack.

isNormal

public boolean isNormal()

Return whether or not this value represents "normal" control-flow. Normal control flow are all blocks outside any catch or finally block.

setNormal

public void setNormal()

Make this value represent "normal" control flow.

isTop

public boolean isTop()

Return whether or not this is the special "top" dataflow value.

setTop

public void setTop()

Make this the special "top" dataflow value.

isBottom

public boolean isBottom()

Return whether or not this is the special "bottom" dataflow value.

setBottom

public void setBottom()

Make this the special "bottom" dataflow value.

copyFrom

public void copyFrom(BlockType other)

Make this object an exact duplicate of given object.

Parameters:

other - the other BlockType object

sameAs

public boolean sameAs(BlockType other)

Return whether or not this object is identical to the one given.

Parameters:

other - the other BlockType object

Returns:

true if this object is identical to the one given, false otherwise

mergeWith

public void mergeWith(BlockType other)

Merge other dataflow value into this value.

Parameters:

other - the other BlockType value

pushCatch

public void pushCatch()

Enter a catch block.

pushFinally

public void pushFinally()

Enter a finally block.

toString

public java.lang.String toString()

Overrides:

toString in class java.util.BitSet