Package edu.umd.cs.findbugs

Class ByteCodePatternDetector

java.lang.Object

edu.umd.cs.findbugs.ByteCodePatternDetector

All Implemented Interfaces:

Detector, Priorities

Direct Known Subclasses:

LazyInit

public abstract class ByteCodePatternDetector
extends Object
implements Detector

A base class for bug detectors that are based on a ByteCodePattern. ByteCodePatterns provide an easy way to detect patterns of bytecode instructions, taking into account control flow and uses of fields and values.

See Also:

• ByteCodePattern

Field Summary

Fields inherited from interface edu.umd.cs.findbugs.Priorities

EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY

Constructor Summary

Constructors

Constructor	Description
ByteCodePatternDetector()

Method Summary

Modifier and Type	Method	Description
protected abstract BugReporter	getBugReporter()
abstract ByteCodePattern	getPattern()	Get the ByteCodePattern for this detector.
abstract boolean	prescreen(org.apache.bcel.classfile.Method method, ClassContext classContext)	Prescreen a method.
void	report()	This method is called after all classes to be visited.
abstract void	reportMatch(ClassContext classContext, org.apache.bcel.classfile.Method method, ByteCodePatternMatch match)	Called to report an instance of the ByteCodePattern.
void	visitClassContext(ClassContext classContext)	Visit the ClassContext for a class which should be analyzed for instances of bug patterns.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ByteCodePatternDetector

public ByteCodePatternDetector()

Method Details

getBugReporter

protected abstract BugReporter getBugReporter()

visitClassContext

public void visitClassContext(ClassContext classContext)

Description copied from interface: Detector

Visit the ClassContext for a class which should be analyzed for instances of bug patterns.

Specified by:

visitClassContext in interface Detector

Parameters:

classContext - the ClassContext

report

public void report()

Description copied from interface: Detector

This method is called after all classes to be visited. It should be used by any detectors which accumulate information over all visited classes to generate results.

Specified by:

report in interface Detector

getPattern

public abstract ByteCodePattern getPattern()

Get the ByteCodePattern for this detector.

prescreen

public abstract boolean prescreen(org.apache.bcel.classfile.Method method,
 ClassContext classContext)

Prescreen a method. It is a valid, but dumb, implementation simply to return true unconditionally. A better implementation is to call ClassContext.getBytecodeSet() to check whether the method actually contains the bytecode instructions that the pattern will look for. The theory is that checking the bytecode set is very fast, while building the MethodGen, CFG, ValueNumberAnalysis, etc. objects required to match ByteCodePatterns is slow, and the bytecode pattern matching algorithm is also not particularly fast.

As a datapoint, prescreening speeds up the BCPDoubleCheck detector by a factor of 5 with no loss of generality and only a dozen or so extra lines of code.

Parameters:

method - the method

classContext - the ClassContext for the method

Returns:

true if the method should be analyzed for instances of the ByteCodePattern

reportMatch

public abstract void reportMatch(ClassContext classContext,
 org.apache.bcel.classfile.Method method,
 ByteCodePatternMatch match)
                          throws CFGBuilderException,
DataflowAnalysisException

Called to report an instance of the ByteCodePattern.

Parameters:

classContext - the ClassContext for the analyzed class

method - the method to instance appears in

match - the ByteCodePatternMatch object representing the match of the ByteCodePattern against actual instructions in the method

Throws:

CFGBuilderException

DataflowAnalysisException