Package edu.umd.cs.findbugs.detect

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 unknwon value are normal priority.

Author:

Mikko Tiihonen

Nested Class Summary

Nested classes/interfaces inherited from class edu.umd.cs.findbugs.bcel.OpcodeStackDetector

OpcodeStackDetector.WithCustomJumpInfo

Field Summary

Fields inherited from class edu.umd.cs.findbugs.bcel.OpcodeStackDetector

stack

Fields inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode

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

Fields inherited from interface edu.umd.cs.findbugs.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
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 edu.umd.cs.findbugs.bcel.OpcodeStackDetector

afterOpcode, beforeOpcode, getStack, isUsingCustomUserValue, visitCode

Methods inherited from class edu.umd.cs.findbugs.BytecodeScanningDetector

getClassContext, report, shouldVisitCode

Methods inherited from class edu.umd.cs.findbugs.visitclass.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 edu.umd.cs.findbugs.visitclass.AnnotationVisitor

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

Methods inherited from class edu.umd.cs.findbugs.visitclass.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 edu.umd.cs.findbugs.visitclass.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 java.lang.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

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

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

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)