Package com.mebigfatguy.fbcontrib.detect

Class MethodReturnsConstant

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
com.mebigfatguy.fbcontrib.detect.MethodReturnsConstant
All Implemented Interfaces:
edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, org.apache.bcel.classfile.Visitor
@CustomUserValue public class MethodReturnsConstant extends edu.umd.cs.findbugs.BytecodeScanningDetector
looks for private methods that can only return one constant value. either the class should not return a value, or perhaps a branch was missed.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final edu.umd.cs.findbugs.BugReporter
    bugReporter
     
    private static final Object
    CONSTANT_DOESNT_EXIST
     
    private Set<org.apache.bcel.classfile.Method>
    overloadedMethods
     
    private Map<Integer,Object>
    registerConstants
     
    private Object
    returnConstant
     
    private int
    returnPC
     
    private Integer
    returnRegister
     
    private edu.umd.cs.findbugs.OpcodeStack
    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
    MethodReturnsConstant(edu.umd.cs.findbugs.BugReporter bugReporter)
    constructs a MRC detector given the reporter to report bugs on

  • Method Summary

    Modifier and Type
    Method
    Description
    private Set<org.apache.bcel.classfile.Method>
    collectOverloadedMethods(org.apache.bcel.classfile.JavaClass cls)
    adds all methods of a class that are overloaded to a set.
    void
    sawOpcode(int seen)
    implements the visitor to look for methods that return a constant
    void
    visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)
    implements the visitor to collect all methods that are overloads.
    void
    visitCode(org.apache.bcel.classfile.Code obj)
    implements the visitor to reset the stack and proceed for private methods

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

    getClassContext, report, shouldVisitCode

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

    afterOpcode, areOppositeBranches, atCatchBlock, beforeOpcode, 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, visit

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

    getAnnotationParameterAsEnum, 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

  • Field Details

    • CONSTANT_DOESNT_EXIST

      private static final Object CONSTANT_DOESNT_EXIST

    • bugReporter

      private final edu.umd.cs.findbugs.BugReporter bugReporter

    • stack

      private edu.umd.cs.findbugs.OpcodeStack stack

    • returnRegister

      private Integer returnRegister

    • registerConstants

      private Map<Integer,Object> registerConstants

    • overloadedMethods

      private Set<org.apache.bcel.classfile.Method> overloadedMethods

    • returnConstant

      private Object returnConstant

    • returnPC

      private int returnPC

  • Constructor Details

    • MethodReturnsConstant

      public MethodReturnsConstant(edu.umd.cs.findbugs.BugReporter bugReporter)
      constructs a MRC detector given the reporter to report bugs on
      Parameters:
      bugReporter - the sync of bug reports

  • Method Details

    • visitClassContext

      public void visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)
      implements the visitor to collect all methods that are overloads. These methods should be ignored, as you may differentiate Const based on parameter type, or value.
      Specified by:
      visitClassContext in interface edu.umd.cs.findbugs.Detector
      Overrides:
      visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector
      Parameters:
      classContext - the currently parsed class object

    • visitCode

      public void visitCode(org.apache.bcel.classfile.Code obj)
      implements the visitor to reset the stack and proceed for private methods
      Specified by:
      visitCode in interface org.apache.bcel.classfile.Visitor
      Overrides:
      visitCode in class edu.umd.cs.findbugs.visitclass.PreorderVisitor
      Parameters:
      obj - the context object of the currently parsed code block

    • sawOpcode

      public void sawOpcode(int seen)
      implements the visitor to look for methods that return a constant
      Overrides:
      sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode
      Parameters:
      seen - the opcode of the currently parsed instruction

    • collectOverloadedMethods

      private Set<org.apache.bcel.classfile.Method> collectOverloadedMethods(org.apache.bcel.classfile.JavaClass cls)
      adds all methods of a class that are overloaded to a set. This method is O(nlogn) so for large classes might be slow. Assuming on average it's better than other choices. When a match is found in the j index, it is removed from the array, so it is not scanned with the i index
      Parameters:
      cls - the class to look for overloaded methods
      Returns:
      the set of methods that are overloaded