Class NumberConstructor

java.lang.Object

edu.umd.cs.findbugs.visitclass.BetterVisitor

edu.umd.cs.findbugs.visitclass.PreorderVisitor

edu.umd.cs.findbugs.visitclass.AnnotationVisitor

edu.umd.cs.findbugs.visitclass.DismantleBytecode

edu.umd.cs.findbugs.BytecodeScanningDetector

edu.umd.cs.findbugs.bcel.OpcodeStackDetector

edu.umd.cs.findbugs.detect.NumberConstructor

All Implemented Interfaces:

Detector, Priorities, org.apache.bcel.classfile.Visitor

public class NumberConstructor
extends OpcodeStackDetector

Detector to find calls to Number constructors with base type argument in Java 5 or newer bytecode. Using new Integer(int) is guaranteed to always result in a new object whereas Integer.valueOf(int) allows caching of values to be done by the javac, JVM class library or JIT. Currently only the JVM class library seems to do caching in the range of -128 to 127. There does not seem to be any caching for float and double which is why those are reported as low priority. All invokes of Number constructor with a constant argument are flagged as high priority and invokes with unknown value are normal priority.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	NumberConstructor.Pair

Nested classes/interfaces inherited from class OpcodeStackDetector

OpcodeStackDetector.WithCustomJumpInfo

Field Summary

Fields

Modifier and Type	Field	Description
private final Map<String, NumberConstructor.Pair>	boxClasses
private final BugAccumulator	bugAccumulator
private final List<MethodDescriptor>	methods

Fields inherited from class OpcodeStackDetector

stack

Fields inherited from class DismantleBytecode

codeBytes, lineNumberTable, M_BR, M_CP, M_INT, M_PAD, M_R, M_UINT

Fields inherited from interface Priorities

EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY

Constructor Summary

Constructors

Constructor	Description
NumberConstructor(BugReporter bugReporter)	Constructs a NC detector given the reporter to report bugs on

Method Summary

Modifier and Type	Method	Description
private MethodDescriptor	getShouldCall()
private void	handle(String className, boolean isFloatingPoint, String sig)
private boolean	matchArguments(String sig1, String sig2)
void	sawOpcode(int seen)	By default, this method will not be called when stack is TOP.
void	visit(org.apache.bcel.classfile.Code obj)
void	visitClassContext(ClassContext classContext)	The detector is only meaningful for Java5 class libraries.

Methods inherited from class OpcodeStackDetector

afterOpcode, beforeOpcode, getStack, isUsingCustomUserValue, visitCode

Methods inherited from class BytecodeScanningDetector

getClassContext, report, shouldVisitCode

Methods inherited from class DismantleBytecode

areOppositeBranches, atCatchBlock, getBranchFallThrough, getBranchOffset, getBranchTarget, getClassConstantOperand, getClassDescriptorOperand, getCodeByte, getConstantRefOperand, getDefaultSwitchOffset, getDottedClassConstantOperand, getFieldDescriptorOperand, getIntConstant, getLongConstant, getMaxPC, getMethodDescriptorOperand, getNameConstantOperand, getNextCodeByte, getNextOpcode, getNextPC, getOpcode, getPC, getPrevOpcode, getRefConstantOperand, getRefFieldIsStatic, getRegisterOperand, getSigConstantOperand, getStringConstantOperand, getSwitchLabels, getSwitchOffsets, getXClassOperand, getXFieldOperand, getXMethodOperand, isBranch, isMethodCall, isRegisterLoad, isRegisterStore, isRegisterStore, isReturn, isShift, isSwitch, isWideOpcode, printOpCode, sawBranchTo, sawClass, sawDouble, sawField, sawFloat, sawIMethod, sawInt, sawLong, sawMethod, sawRegister, sawString

Methods inherited from class AnnotationVisitor

getAnnotationParameterAsEnum, getAnnotationParameterAsString, getAnnotationParameterAsStringArray, visitAnnotation, visitAnnotation, visitParameterAnnotation, visitParameterAnnotation, visitSyntheticParameterAnnotation

Methods inherited from class PreorderVisitor

amVisitingMainMethod, asUnsignedByte, doVisitMethod, getClassDescriptor, getClassName, getCode, getConstantPool, getDottedClassName, getDottedFieldSig, getDottedMethodSig, getDottedSuperclassName, getField, getFieldDescriptor, getFieldIsStatic, getFieldName, getFieldSig, getFullyQualifiedFieldName, getFullyQualifiedMethodName, getMethod, getMethodDescriptor, getMethodName, getMethodSig, getMethodVisitOrder, getNumberArguments, getNumberMethodArguments, getPackageName, getSizeOfSurroundingTryBlock, getSizeOfSurroundingTryBlock, getSourceFile, getStringFromIndex, getSuperclassName, getSurroundingCaughtExceptions, getSurroundingCaughtExceptions, getSurroundingCaughtExceptionTypes, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitBootstrapMethods, visitConstantInvokeDynamic, visitConstantMethodHandle, visitConstantMethodType, visitConstantModule, visitConstantPackage, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitMethodParameters, visitParameterAnnotationEntry, visitStackMap, visitStackMapEntry

Methods inherited from class BetterVisitor

clone, report, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitCodeException, visitConstantClass, visitConstantDouble, visitConstantFieldref, visitConstantFloat, visitConstantInteger, visitConstantInterfaceMethodref, visitConstantLong, visitConstantMethodref, visitConstantNameAndType, visitConstantString, visitConstantUtf8, visitConstantValue, visitDeprecated, visitExceptionTable, visitField, visitInnerClass, visitLineNumber, visitLocalVariable, visitLocalVariableTypeTable, visitMethod, visitSignature, visitSourceFile, visitSynthetic, visitUnknown

Methods inherited from class Object

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

Methods inherited from interface org.apache.bcel.classfile.Visitor

visitConstantDynamic, visitMethodParameter, visitModule, visitModuleExports, visitModuleMainClass, visitModuleOpens, visitModulePackages, visitModuleProvides, visitModuleRequires, visitNestHost, visitNestMembers, visitRecord, visitRecordComponent, visitStackMapType

Field Details

boxClasses

private final Map<String, NumberConstructor.Pair> boxClasses

methods

private final List<MethodDescriptor> methods

bugAccumulator

private final BugAccumulator bugAccumulator

Constructor Details

NumberConstructor

public NumberConstructor(BugReporter bugReporter)

Constructs a NC detector given the reporter to report bugs on

Parameters:

bugReporter - the sync of bug reports

Method Details

handle

private void handle(@SlashedClassName
 String className,
 boolean isFloatingPoint,
 String sig)

visitClassContext

public void visitClassContext(ClassContext classContext)

The detector is only meaningful for Java5 class libraries.

Specified by:

visitClassContext in interface Detector

Overrides:

visitClassContext in class BytecodeScanningDetector

Parameters:

classContext - the context object that holds the JavaClass parsed

visit

public void visit(org.apache.bcel.classfile.Code obj)

Overrides:

visit in class DismantleBytecode

matchArguments

private boolean matchArguments(String sig1,
 String sig2)

getShouldCall

@CheckForNull
private MethodDescriptor getShouldCall()

sawOpcode

public void sawOpcode(int seen)

Description copied from class: OpcodeStackDetector

By default, this method will not be called when stack is TOP. To change this behavior, override #beforeOpcode(int) and change to return true even if stack is TOP.

see Using FindBugs for Research to learn lattice and what TOP means.

Specified by:

sawOpcode in class OpcodeStackDetector

See Also:

• OpcodeStackDetector.beforeOpcode(int)