Operators

The operators are preprocessors or comparators in the corresponding phases of the pipeline. They're grouped as operators, because it's possible to achieve the same results with both. The only difference is the way they work. We illustrate this fact in another tutorial.
As an example, in an AST-based pipeline you could use a preprocessor to generalize the original source code by deleting nodes in the tree. But you could also use a comparator which considers all method declarations identical by ignoring their names.
The operators can be divided into two groups - independent and dependent. Independent operators work alone. Dependent operators need other operators to work.

Independent operators

Annotators

Name	Description
HeightAnnotator	Annotates each node with the number of the underlying nodes and blocks. Needed for HeightPoolingStrategy	P
MarkVariablesWithParentID	Annotates all nodes that represents variable names with the id of their parent node. Needed for RenameVariableNamesConsistent	P
NodeCountAnnotator	Annotates all nodes with the number of underlying nodes.	P
TokenLengthAnnotator	Annotates all nodes with the number of underlying tokens.	P
TokenTypesAnnotator	Annotates all nodes with the number of underlying different type tokens.	P

Methods

Name	Description	Example
GeneralizeMethodArgument- Types	Removes types of the method argements	void setX(int x) becomes void setX(x)	P
GeneralizeMethodCallNames	Removes method calls		P
GeneralizeMethodDecleration- Names	Removes method decleration		P
GeneralizeMethodReturnTypes	Removes returntype	int getX() becomes getX()	P
RemoveEmptyMethods	Removes methods without block element	abstract method declerations or when RemoveEmptyBlocks was used on a method with a empty block	P
RemoveGetMethodDeclerations	Removes all declerations of getter-methods	String getName(){...}	P
RemoveIsMethodDeclerations	Removes all declerations of is-methods	boolean isViewable(){...}	P
RemoveSetMethodDeclerations	Removes all declerations of setter-methods	void setName(String name) {...}	P
RemoveSimpleMethods	Removes methods with only one element		P

Operators

Name	Description	Example
AcceptAdditiveOperators	Ignores if an operator is plus or minus		C
AcceptAnds	Ignores and operators	& and &&	C
AcceptArithmeticOperators	Ignores arithmetic operators	+, -, *, / and %	C
AcceptAssignments	Ignores difference between all assignments		C
AcceptBitOperators	Ignores difference between bit operators		C
AcceptBooleanKeywords	Ignores difference between true and false		C
AcceptCharacterLiterals	Ignores difference between character literals	'a' = 'b'	C
AcceptDecrementsOperators	Ignores post- and predcrement operators		C
AcceptEquals	Ignores == and !=		C
AcceptIncrementOperators	Ignores post- and preincrement operators		C
AcceptIntegralOperators	Ignores all integral operators		C
AcceptLogicalOperators	Ignores all logic operators	\|\|, &&, \|, &	C
AcceptMultiplicativeOperators	Ignores all multiplicative operators	*, /, %	C
AcceptOperators	Ignores all operators except logical		C
AcceptOrs	Ignores or operators	\| and \|\|	C
AcceptRelationOperators	Ignores all relation operators	==, !=, <, <=, >, >=	C
AcceptShiftOperators	Ignores all shift operators	<<, >>, >>>
CollapsePostfixOperators	Removes all postfix operators	i++ becomes i	P
CollapsePrefixOperators	Removes all prefix operators	--i becomes i	P
CollapseUnaryOperators	Removes all unary operators	~i becomes i	P
CollapseUnaryPlus	Removes unary plusses	+i becomes i	P

Variables and types

Name	Description	Example
AcceptNumberLiterals	Ignores all numbers		C
AcceptNumberTypeNames	Ignores number types	int, float, dobule, char etc.	C
AcceptPrimitives	Ignores numbers, true and false		C
AcceptPrimitiveTypes	Ignores primitive types (numeric and boolean)		C
AcceptStringLiterals	Ignores all string literals	"JCCD" = "UNIX"	C
CollapseArrayElementAccess	Removes array accesses	a[0][1] becomes a	P
CollapseCastExpressions	Removes casts	(int)a becomes a	P
GeneralizeArrayInitializers	Ignores different array initializations	int[] a = {1,2,3} equals int[] a = new int[]{7}	P
GeneralizeNewOperatorTypes	Generalizes all object instancings	a = new Car(); becomes a;	P
GeneralizeTypes	Removes all types from sourcecode		P
GeneralizeVariableDecleration- Types	Removes types of variable declerations		P
GeneralizeVariableNames	Removes all variable names		P
NumberLiteralToDouble	Ignores representation of numbers	97.0 = 97f = a
RemoveGenericTypes	Removes generic types	Vector<String> becomes Vector	P
RemoveVariableDecleration- Nodes	Removes all variable declerations		P
RenameVariableNamesLocal-Consistent	Renames variables consistent inside of blocks. The renaming is annotated in the corresponding node.		P

Class / File

Name	Description	Example
AcceptClassKinds	Ignores class, enum and interface keywords		C
AcceptFileName	Ignores file names		C
AcceptIdentifiers	Ignores all identifiers		C
AcceptVariableIdentifiers	Ignores all variable identifiers		C
CompleteToBlock	Adds blocks to for, do, else, if and while when there are only single arguments.	if(true) make(); becomes if(true){ make(); }	P
GeneralizeClassDecleration- Name	Removes class decleration name		P
ReduceIdentifiersToCapital-LetterSubstring	Reduces fully qualified identifiers to the part that begins with a capital.	my.package.Foo.Bar becomes Foo.Bar	P
ReduceIdentifiersToLast-Substring	Reduces fully qualified identifiers to the last substring.	my.package.Foo.Bar becomes Bar	P
RemoveAnnotations	Removes all annotations in the source code		P
RemoveAssertions	Removes all assertions introduced through the keyword assert		P
RemoveEmptyBlocks	Removes empty blocks		P
RemoveEmptyGroupNodes	Removes all group nodes which don't have children		P
RemoveExtends	Removes the extends-parts at the class and interface declaration		P
RemoveImplements	Removes the implements-parts at the class declaration		P
RemoveImports	Removes all imports		P
RemoveInterfaces	Removes all interfaces		P
RemoveModifiers	Removes all modifiers	final public void doIt(){...} becomes void doIt(){...}	P
RemovePackageInformation	Removes package information		P
RemoveRedundantParantheses	Removes unnecessary parantheses	((1 + 2) * 3) becomes (1 + 2) * 3	P
RemoveSemicolons	Removes all semicolens		P
RemoveThrow	Removes all throws introduced through the keyword throw		P
RemoveThrowsClause	Removes the throws-parts at the method decleration		P

Technical

Name	Description
AlwaysTrueAndComperator	Assumes that two nodes are always the same	C
AlwaysTrueOrComperator	Assumes that two nodes are always the same	C
CheckEquality	Checks if two node have the same type, number of children and text.	C
CollapseQualifiedTypeIdent- Nodes	Technical: Removes qualified type ident nodes from the AST. Saves some space after using RemoveGenericTypes.	P

Dependent operators

Variables

Name	Description
CheckAnnotatedVariableNames	Checks if the annotated variable names are equal. Needs RenameVariableNames	C
CheckConsistentVariableNames	Like CheckAnnotatedVariableNames, but checks also recursively all children	C
RenameVariableNames-Consistent	Renames variables consistent in the whole sourcecode. The renaming is annotated in the corresponding node. Needs MarkVariablesWithParentID	P

JCCD – A Flexible Java Code Clone Detector API

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Operators

Independent operators

Annotators

Methods

Operators

Variables and types

Class / File

Technical

Dependent operators

Variables