Package javassist.bytecode.analysis
Class MultiType
- java.lang.Object
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- javassist.bytecode.analysis.Type
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- javassist.bytecode.analysis.MultiType
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public class MultiType extends Type
MultiType represents an unresolved type. Whenever twoType
instances are merged, if they share more than one super type (either an interface or a superclass), then aMultiType
is used to represent the possible super types. The goal of aMultiType
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 theMultiType
is passed as an argument toType.isAssignableFrom(Type)
, as well as removing non-intersecting types during a merge. Note: Currently theMultiType
instance is reused as much as possible so that updates are visible from all frames. In addition, allMultiType
merge paths are also updated. This is somewhat hackish, but it appears to handle most scenarios.- Author:
- Jason T. Greene
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
equals(java.lang.Object o)
Type
getComponent()
Always returns null since this type is never used for an array.CtClass
getCtClass()
Gets the class that corresponds with this type.int
getSize()
Always returns 1, since this type is a reference.int
hashCode()
boolean
isArray()
Always reutnrs false since this type is never used for an arrayboolean
isAssignableFrom(Type type)
Determines whether this type is assignable, to the passed type.boolean
isAssignableTo(Type type)
boolean
isReference()
Always returns true, since this type is always a reference.Type
merge(Type type)
Finds the common base type, or interface which both this and the specified type can be assigned.java.lang.String
toString()
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Methods inherited from class javassist.bytecode.analysis.Type
get, getDimensions, isSpecial
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Method Detail
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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 classType
- Returns:
- the class for this type, or null if special
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getComponent
public Type getComponent()
Always returns null since this type is never used for an array.- Overrides:
getComponent
in classType
- Returns:
- the array component if an array, otherwise null
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getSize
public int getSize()
Always returns 1, since this type is a reference.
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isArray
public boolean isArray()
Always reutnrs false since this type is never used for an array
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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 classType
- Parameters:
type
- the type to test assignability to- Returns:
- true if this is assignable to type, otherwise false
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isAssignableTo
public boolean isAssignableTo(Type type)
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isReference
public boolean isReference()
Always returns true, since this type is always a reference.- Overrides:
isReference
in classType
- Returns:
- true
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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 aMultiType
, or aMultiArrayType
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.
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