com.mebigfatguy.fbcontrib.detect

Class ExceptionSoftening

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.ExceptionSoftening

All Implemented Interfaces:

edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, edu.umd.cs.findbugs.visitclass.Constants2, org.apache.bcel.classfile.Visitor, org.apache.bcel.Constants

public class ExceptionSoftening
extends edu.umd.cs.findbugs.BytecodeScanningDetector

looks for methods that catch checked exceptions, and throw unchecked exceptions in their place. There are several levels of concern. Least important are methods constrained by interface or super class contracts not to throw checked exceptions but appear owned by the same author. Next are methods constrained by interface or super class contracts and throw other types of checked exceptions. Lastly are method not constrained by any interface or superclass contract.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ExceptionSoftening.CatchInfo holds information about a catch block the start and end pcs, as well as the exception signature.

Field Summary

Fields

Modifier and Type	Field and Description
private edu.umd.cs.findbugs.BugReporter	bugReporter
private int	catchFalseReturnPC
private java.util.Map<java.lang.Integer,org.apache.bcel.classfile.CodeException>	catchHandlerPCs
private java.util.List<ExceptionSoftening.CatchInfo>	catchInfos
private java.util.Map<java.lang.String,java.util.Set<java.lang.String>>	constrainingInfo
private boolean	hasValidFalseReturn
private boolean	isBooleanMethod
private org.apache.bcel.classfile.LocalVariableTable	lvt
private org.apache.bcel.classfile.JavaClass	runtimeClass
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

Fields inherited from interface org.apache.bcel.Constants

AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_SYPER, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACCESS_NAMES, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ANEWARRAY_QUICK, APPEND_FRAME, APPEND_FRAME_MAX, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, ATTR_ANNOTATION_DEFAULT, ATTR_CODE, ATTR_CONSTANT_VALUE, ATTR_DEPRECATED, ATTR_ENCLOSING_METHOD, ATTR_EXCEPTIONS, ATTR_INNER_CLASSES, ATTR_LINE_NUMBER_TABLE, ATTR_LOCAL_VARIABLE_TABLE, ATTR_LOCAL_VARIABLE_TYPE_TABLE, ATTR_PMG, ATTR_RUNTIME_VISIBLE_ANNOTATIONS, ATTR_RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_SIGNATURE, ATTR_SOURCE_FILE, ATTR_STACK_MAP, ATTR_STACK_MAP_TABLE, ATTR_SYNTHETIC, ATTR_UNKNOWN, ATTRIBUTE_NAMES, BALOAD, BASTORE, BIPUSH, BREAKPOINT, CALOAD, CASTORE, CHECKCAST, CHECKCAST_QUICK, CHOP_FRAME, CHOP_FRAME_MAX, CLASS_TYPE_NAMES, CONSTANT_Class, CONSTANT_Double, CONSTANT_Fieldref, CONSTANT_Float, CONSTANT_Integer, CONSTANT_InterfaceMethodref, CONSTANT_InvokeDynamic, CONSTANT_Long, CONSTANT_MethodHandle, CONSTANT_Methodref, CONSTANT_MethodType, CONSTANT_NameAndType, CONSTANT_NAMES, CONSTANT_String, CONSTANT_Utf8, CONSTRUCTOR_NAME, CONSUME_STACK, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, FULL_FRAME, GETFIELD, GETFIELD_QUICK, GETFIELD_QUICK_W, GETFIELD2_QUICK, GETSTATIC, GETSTATIC_QUICK, GETSTATIC2_QUICK, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILLEGAL_OPCODE, ILLEGAL_TYPE, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMPDEP1, IMPDEP2, IMUL, INEG, INSTANCEOF, INSTANCEOF_QUICK, INT2BYTE, INT2CHAR, INT2SHORT, INTERFACES_IMPLEMENTED_BY_ARRAYS, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKEINTERFACE_QUICK, INVOKENONVIRTUAL, INVOKENONVIRTUAL_QUICK, INVOKESPECIAL, INVOKESTATIC, INVOKESTATIC_QUICK, INVOKESUPER_QUICK, INVOKEVIRTUAL, INVOKEVIRTUAL_QUICK, INVOKEVIRTUAL_QUICK_W, INVOKEVIRTUALOBJECT_QUICK, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, ITEM_Bogus, ITEM_Double, ITEM_Float, ITEM_InitObject, ITEM_Integer, ITEM_Long, ITEM_NAMES, ITEM_NewObject, ITEM_Null, ITEM_Object, IUSHR, IXOR, JSR, JSR_W, KNOWN_ATTRIBUTES, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_QUICK, LDC_W, LDC_W_QUICK, LDC2_W, LDC2_W_QUICK, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MAJOR, MAJOR_1_1, MAJOR_1_2, MAJOR_1_3, MAJOR_1_4, MAJOR_1_5, MAJOR_1_6, MAJOR_1_7, MAJOR_1_8, MAX_ACC_FLAG, MAX_BYTE, MAX_CODE_SIZE, MAX_CP_ENTRIES, MAX_SHORT, MINOR, MINOR_1_1, MINOR_1_2, MINOR_1_3, MINOR_1_4, MINOR_1_5, MINOR_1_6, MINOR_1_7, MINOR_1_8, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, MULTIANEWARRAY_QUICK, NEW, NEW_QUICK, NEWARRAY, NO_OF_OPERANDS, NOP, OPCODE_NAMES, POP, POP2, PRODUCE_STACK, PUSH, PUTFIELD, PUTFIELD_QUICK, PUTFIELD_QUICK_W, PUTFIELD2_QUICK, PUTSTATIC, PUTSTATIC_QUICK, PUTSTATIC2_QUICK, RESERVED, RET, RETURN, SALOAD, SAME_FRAME, SAME_FRAME_EXTENDED, SAME_FRAME_MAX, SAME_LOCALS_1_STACK_ITEM_FRAME, SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED, SAME_LOCALS_1_STACK_ITEM_FRAME_MAX, SASTORE, SHORT_TYPE_NAMES, SIPUSH, STATIC_INITIALIZER_NAME, SWAP, SWITCH, T_ADDRESS, T_ARRAY, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_OBJECT, T_REFERENCE, T_SHORT, T_UNKNOWN, T_VOID, TABLESWITCH, TYPE_NAMES, TYPE_OF_OPERANDS, UNDEFINED, UNPREDICTABLE, WIDE

Constructor Summary

Constructors

Constructor and Description
ExceptionSoftening(edu.umd.cs.findbugs.BugReporter bugReporter) constructs a EXS detector given the reporter to report bugs on.

Method Summary

Modifier and Type	Method and Description
private java.util.Map<java.lang.String,java.util.Set<java.lang.String>>	buildConstrainingInfo(org.apache.bcel.classfile.JavaClass cls, org.apache.bcel.classfile.Method m) returns exception names describing what exceptions are allowed to be thrown
private static java.util.LinkedHashMap<java.lang.Integer,org.apache.bcel.classfile.CodeException>	collectExceptions(org.apache.bcel.classfile.CodeException... exceptions) collects all the valid exception objects (ones where start and finish are before the target) and with a catch type
private static org.apache.bcel.classfile.Method	findMethod(org.apache.bcel.classfile.JavaClass cls, java.lang.String methodName, java.lang.String methodSig) finds a method that matches the name and signature in the given class
private static java.util.Set<java.lang.String>	findPossibleCatchSignatures(java.util.List<ExceptionSoftening.CatchInfo> infos, int pc) returns an array of catch types that the current pc is in
private java.util.Map<java.lang.String,java.util.Set<java.lang.String>>	getConstrainingInfo(org.apache.bcel.classfile.JavaClass cls, org.apache.bcel.classfile.Method m) finds the super class or interface that constrains the types of exceptions that can be thrown from the given method
private boolean	prescreen(org.apache.bcel.classfile.Method method) returns whether a method explicitly throws an exception
private void	processBooleanReturn()
private void	processThrow()
private static void	removeFinishedCatchBlocks(java.util.List<ExceptionSoftening.CatchInfo> infos, int pc) remove catchinfo blocks from the map where the handler end is before the current pc
void	sawOpcode(int seen) overrides the visitor to find catch blocks that throw runtime exceptions
private void	updateEndPCsOnCatchRegScope(java.util.List<ExceptionSoftening.CatchInfo> infos, int pc, int seen) reduces the end pc based on the optional LocalVariableTable's exception register scope
void	visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext) overrides the visitor to reset the stack
void	visitCode(org.apache.bcel.classfile.Code obj) overrides the visitor to look for methods that catch checked exceptions and rethrow runtime exceptions

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

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, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitStackMapTable, visitStackMapTableEntry

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, visitStackMap, visitStackMapEntry, visitSynthetic, visitUnknown

Methods inherited from class java.lang.Object

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

Field Detail

bugReporter

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

runtimeClass

private org.apache.bcel.classfile.JavaClass runtimeClass

stack

private edu.umd.cs.findbugs.OpcodeStack stack

catchHandlerPCs

private java.util.Map<java.lang.Integer,org.apache.bcel.classfile.CodeException> catchHandlerPCs

catchInfos

private java.util.List<ExceptionSoftening.CatchInfo> catchInfos

lvt

private org.apache.bcel.classfile.LocalVariableTable lvt

constrainingInfo

private java.util.Map<java.lang.String,java.util.Set<java.lang.String>> constrainingInfo

isBooleanMethod

private boolean isBooleanMethod

hasValidFalseReturn

private boolean hasValidFalseReturn

catchFalseReturnPC

private int catchFalseReturnPC

Constructor Detail

ExceptionSoftening

public ExceptionSoftening(edu.umd.cs.findbugs.BugReporter bugReporter)

constructs a EXS detector given the reporter to report bugs on.

Parameters:

bugReporter - the sync of bug reports

Method Detail

visitClassContext

public void visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)

overrides the visitor to reset the stack

Specified by:

visitClassContext in interface edu.umd.cs.findbugs.Detector

Overrides:

visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector

Parameters:

classContext - the context object of the currently parsed class

visitCode

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

overrides the visitor to look for methods that catch checked exceptions and rethrow runtime exceptions

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)

overrides the visitor to find catch blocks that throw runtime exceptions

Overrides:

sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode

Parameters:

seen - the opcode of the currently parsed instruction

processThrow

private void processThrow()

processBooleanReturn

private void processBooleanReturn()

collectExceptions

private static java.util.LinkedHashMap<java.lang.Integer,org.apache.bcel.classfile.CodeException> collectExceptions(org.apache.bcel.classfile.CodeException... exceptions)

collects all the valid exception objects (ones where start and finish are before the target) and with a catch type

Parameters:

exceptions - the exceptions from the class file

Returns:

the filtered exceptions keyed by catch end pc

removeFinishedCatchBlocks

private static void removeFinishedCatchBlocks(java.util.List<ExceptionSoftening.CatchInfo> infos,
                                              int pc)

remove catchinfo blocks from the map where the handler end is before the current pc

Parameters:

infos - the exception handlers installed

pc - the current pc

updateEndPCsOnCatchRegScope

private void updateEndPCsOnCatchRegScope(java.util.List<ExceptionSoftening.CatchInfo> infos,
                                         int pc,
                                         int seen)

reduces the end pc based on the optional LocalVariableTable's exception register scope

Parameters:

infos - the list of active catch blocks

pc - the current pc

seen - the currently parsed opcode

findPossibleCatchSignatures

private static java.util.Set<java.lang.String> findPossibleCatchSignatures(java.util.List<ExceptionSoftening.CatchInfo> infos,
                                                                           int pc)

returns an array of catch types that the current pc is in

Parameters:

infos - the list of catch infos for this method

pc - the current pc

Returns:

an set of catch exception types that the pc is currently in

getConstrainingInfo

@Nullable
private java.util.Map<java.lang.String,java.util.Set<java.lang.String>> getConstrainingInfo(org.apache.bcel.classfile.JavaClass cls,
                                                                                                      org.apache.bcel.classfile.Method m)
                                                                                               throws java.lang.ClassNotFoundException

finds the super class or interface that constrains the types of exceptions that can be thrown from the given method

Parameters:

cls - the currently parsed class

m - the method to check

Returns:

a map containing the class name to a set of exceptions that constrain this method

Throws:

java.lang.ClassNotFoundException - if a super class or super interface can't be loaded from the repository

findMethod

@Nullable
private static org.apache.bcel.classfile.Method findMethod(org.apache.bcel.classfile.JavaClass cls,
                                                                     java.lang.String methodName,
                                                                     java.lang.String methodSig)

finds a method that matches the name and signature in the given class

Parameters:

cls - the class to look in

methodName - the name to look for

methodSig - the signature to look for

Returns:

the method or null

buildConstrainingInfo

private java.util.Map<java.lang.String,java.util.Set<java.lang.String>> buildConstrainingInfo(org.apache.bcel.classfile.JavaClass cls,
                                                                                              org.apache.bcel.classfile.Method m)
                                                                                       throws java.lang.ClassNotFoundException

returns exception names describing what exceptions are allowed to be thrown

Parameters:

cls - the cls to find the exceptions in

m - the method to add exceptions from

Returns:

a map with one entry of a class name to a set of exceptions that constrain what can be thrown.

Throws:

java.lang.ClassNotFoundException - if an exception class can't be loaded from the repository

prescreen

private boolean prescreen(org.apache.bcel.classfile.Method method)

returns whether a method explicitly throws an exception

Parameters:

method - the currently parsed method

Returns:

if the method throws an exception