Package org.codehaus.groovy.ast.tools

Class WideningCategories

  • public class WideningCategories
extends Object
    This class provides helper methods to determine the type from a widening operation for example for a plus operation.

    To determine the resulting type of for example a=exp1+exp2 we look at the conditions isIntCategory(ClassNode), isLongCategory(ClassNode), isBigIntCategory(ClassNode), isDoubleCategory(ClassNode) and isBigDecCategory(ClassNode) in that order. The first case applying to exp1 and exp2 is defining the result type of the expression.

    If for example you look at x = 1 + 2l we have the first category applying to the number 1 being int, since the 1 is an int. The 2l is a long, therefore the int category will not apply and the result type can't be int. The next category in the list is long, and since both apply to long, the result type is a long.

    • Constructor Detail

      • WideningCategories

        public WideningCategories()

    • Method Detail

      • isInt

        public static boolean isInt​(ClassNode type)
        Used to check if a type is an int or Integer.
        Parameters:
        type - the type to check

      • isDouble

        public static boolean isDouble​(ClassNode type)
        Used to check if a type is an double or Double.
        Parameters:
        type - the type to check

      • isFloat

        public static boolean isFloat​(ClassNode type)
        Used to check if a type is a float or Float.
        Parameters:
        type - the type to check

      • isIntCategory

        public static boolean isIntCategory​(ClassNode type)
        It is of an int category, if the provided type is a byte, char, short, int.

      • isLongCategory

        public static boolean isLongCategory​(ClassNode type)
        It is of a long category, if the provided type is a long, its wrapper or if it is a long category.

      • isBigIntCategory

        public static boolean isBigIntCategory​(ClassNode type)
        It is of a BigInteger category, if the provided type is a long category or a BigInteger.

      • isBigDecCategory

        public static boolean isBigDecCategory​(ClassNode type)
        It is of a BigDecimal category, if the provided type is a BigInteger category or a BigDecimal.

      • isDoubleCategory

        public static boolean isDoubleCategory​(ClassNode type)
        It is of a double category, if the provided type is a BigDecimal, a float, double. C(type)=double

      • isFloatingCategory

        public static boolean isFloatingCategory​(ClassNode type)
        It is of a floating category, if the provided type is a a float, double. C(type)=float

      • isNumberCategory

        public static boolean isNumberCategory​(ClassNode type)

      • lowestUpperBound

        public static ClassNode lowestUpperBound​(List<ClassNode> nodes)
        Given a list of class nodes, returns the first common supertype. For example, Double and Float would return Number, while Set and String would return Object.
        Parameters:
        nodes - the list of nodes for which to find the first common super type.
        Returns:
        first common supertype

      • lowestUpperBound

        public static ClassNode lowestUpperBound​(ClassNode a,
                                         ClassNode b)
        Given two class nodes, returns the first common supertype, or the class itself if there are equal. For example, Double and Float would return Number, while Set and String would return Object. This method is not guaranteed to return a class node which corresponds to a real type. For example, if two types have more than one interface in common and are not in the same hierarchy branch, then the returned type will be a virtual type implementing all those interfaces. Calls to this method are supposed to be made with resolved generics. This means that you can have wildcards, but no placeholder.
        Parameters:
        a - first class node
        b - second class node
        Returns:
        first common supertype

      • implementsInterfaceOrSubclassOf

        public static boolean implementsInterfaceOrSubclassOf​(ClassNode source,
                                                      ClassNode targetType)
        Determines if the source class implements an interface or subclasses the target type. This method takes the lowest upper bound class node type into account, allowing to remove unnecessary casts.
        Parameters:
        source - the type of interest
        targetType - the target type of interest