Package javassist.bytecode.analysis

Class MultiType

  • public class MultiType
extends Type
    MultiType represents an unresolved type. Whenever two Type instances are merged, if they share more than one super type (either an interface or a superclass), then a MultiType is used to represent the possible super types. The goal of a MultiType is to reduce the set of possible types down to a single resolved type. This is done by eliminating non-assignable types from the typeset when the MultiType is passed as an argument to Type.isAssignableFrom(Type), as well as removing non-intersecting types during a merge. Note: Currently the MultiType instance is reused as much as possible so that updates are visible from all frames. In addition, all MultiType merge paths are also updated. This is somewhat hackish, but it appears to handle most scenarios.
    Author:
    Jason T. Greene

    • Constructor Detail

      • MultiType

        public MultiType​(java.util.Map<java.lang.String,​CtClass> interfaces)

      • MultiType

        public MultiType​(java.util.Map<java.lang.String,​CtClass> interfaces,
                 Type potentialClass)

    • Method Detail

      • getCtClass

        public CtClass getCtClass()
        Gets the class that corresponds with this type. If this information is not yet known, java.lang.Object will be returned.
        Overrides:
        getCtClass in class Type
        Returns:
        the class for this type, or null if special

      • getComponent

        public Type getComponent()
        Always returns null since this type is never used for an array.
        Overrides:
        getComponent in class Type
        Returns:
        the array component if an array, otherwise null

      • getSize

        public int getSize()
        Always returns 1, since this type is a reference.
        Overrides:
        getSize in class Type
        Returns:
        the number of words needed to hold this type

      • isArray

        public boolean isArray()
        Always reutnrs false since this type is never used for an array
        Overrides:
        isArray in class Type
        Returns:
        true if an array, false if not

      • isAssignableFrom

        public boolean isAssignableFrom​(Type type)
        Description copied from class: Type
        Determines whether this type is assignable, to the passed type. A type is assignable to another if it is either the same type, or a sub-type.
        Overrides:
        isAssignableFrom in class Type
        Parameters:
        type - the type to test assignability to
        Returns:
        true if this is assignable to type, otherwise false

      • isAssignableTo

        public boolean isAssignableTo​(Type type)

      • isReference

        public boolean isReference()
        Always returns true, since this type is always a reference.
        Overrides:
        isReference in class Type
        Returns:
        true

      • merge

        public Type merge​(Type type)
        Description copied from class: Type
        Finds the common base type, or interface which both this and the specified type can be assigned. If there is more than one possible answer, then a MultiType, or a MultiArrayType is returned. Multi-types have special rules, and successive merges and assignment tests on them will alter their internal state, as well as other multi-types they have been merged with. This method is used by the data-flow analyzer to merge the type state from multiple branches.
        Overrides:
        merge in class Type
        Parameters:
        type - the type to merge with
        Returns:
        the merged type

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Type

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class Type

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class Type