Module lettuce.core
Package io.lettuce.core.dynamic.support

Class ResolvableType

java.lang.Object
io.lettuce.core.dynamic.support.ResolvableType
All Implemented Interfaces:
Serializable
public class ResolvableType
extends Object
implements Serializable
Encapsulates a Java Type, providing access to supertypes, interfaces, and generic parameters along with the ability to ultimately resolve to a Class.
See Also:
Serialized Form

  • Field Details

    • NONE

      public static final ResolvableType NONE
      ResolvableType returned when no value is available. NONE is used in preference to null so that multiple method calls can be safely chained.

  • Method Details

    • getType

      public Type getType()
      Return the underling Java Type being managed. With the exception of the NONE constant, this method will never return null.

    • getRawClass

      public Class<?> getRawClass()
      Return the underlying Java Class being managed, if available; otherwise null.

    • getSource

      public Object getSource()
      Return the underlying source of the resolvable type. Will return a Field, MethodParameter or Type depending on how the ResolvableType was constructed. With the exception of the NONE constant, this method will never return null. This method is primarily to provide access to additional type information or meta-data that alternative JVM languages may provide.

    • isInstance

      public boolean isInstance​(Object obj)
      Determine whether the given object is an instance of this ResolvableType.
      Parameters:
      obj - the object to check
      See Also:
      isAssignableFrom(Class)

    • isAssignableFrom

      public boolean isAssignableFrom​(Class<?> other)
      Determine whether this ResolvableType is assignable from the specified other type.
      Parameters:
      other - the type to be checked against (as a Class)
      See Also:
      isAssignableFrom(ResolvableType)

    • isAssignableFrom

      public boolean isAssignableFrom​(ResolvableType other)
      Determine whether this ResolvableType is assignable from the specified other type.

      Attempts to follow the same rules as the Java compiler, considering whether both the resolved Class is assignable from the given type as well as whether all generics are assignable.

      Parameters:
      other - the type to be checked against (as a ResolvableType)
      Returns:
      true if the specified other type can be assigned to this ResolvableType; false otherwise

    • isArray

      public boolean isArray()
      Return true if this type resolves to a Class that represents an array.
      See Also:
      getComponentType()

    • getComponentType

      public ResolvableType getComponentType()
      Return the ResolvableType representing the component type of the array or NONE if this type does not represent an array.
      See Also:
      isArray()

    • asCollection

      public ResolvableType asCollection()
      Convenience method to return this type as a resolvable Collection type. Returns NONE if this type does not implement or extend Collection.
      See Also:
      as(Class), asMap()

    • asMap

      public ResolvableType asMap()
      Convenience method to return this type as a resolvable Map type. Returns NONE if this type does not implement or extend Map.
      See Also:
      as(Class), asCollection()

    • as

      public ResolvableType as​(Class<?> type)
      Return this type as a ResolvableType of the specified class. Searches supertype and interface hierarchies to find a match, returning NONE if this type does not implement or extend the specified class.
      Parameters:
      type - the required class type
      Returns:
      a ResolvableType representing this object as the specified type, or NONE if not resolvable as that type
      See Also:
      asCollection(), asMap(), getSuperType(), getInterfaces()

    • getSuperType

      public ResolvableType getSuperType()
      Return a ResolvableType representing the direct supertype of this type. If no supertype is available this method returns NONE.
      See Also:
      getInterfaces()

    • getInterfaces

      public ResolvableType[] getInterfaces()
      Return a ResolvableType array representing the direct interfaces implemented by this type. If this type does not implement any interfaces an empty array is returned.
      See Also:
      getSuperType()

    • hasGenerics

      public boolean hasGenerics()
      Return true if this type contains generic parameters.
      See Also:
      getGeneric(int...), getGenerics()

    • hasUnresolvableGenerics

      public boolean hasUnresolvableGenerics()
      Determine whether the underlying type has any unresolvable generics: either through an unresolvable type variable on the type itself or through implementing a generic interface in a raw fashion, i.e. without substituting that interface's type variables. The result will be true only in those two scenarios.

    • getNested

      public ResolvableType getNested​(int nestingLevel)
      Return a ResolvableType for the specified nesting level. See getNested(int, Map) for details.
      Parameters:
      nestingLevel - the nesting level
      Returns:
      the ResolvableType type, or #NONE

    • getNested

      public ResolvableType getNested​(int nestingLevel, Map<Integer,​Integer> typeIndexesPerLevel)
      Return a ResolvableType for the specified nesting level. The nesting level refers to the specific generic parameter that should be returned. A nesting level of 1 indicates this type; 2 indicates the first nested generic; 3 the second; and so on. For example, given List<Set<Integer>> level 1 refers to the List, level 2 the Set, and level 3 the Integer.

      The typeIndexesPerLevel map can be used to reference a specific generic for the given level. For example, an index of 0 would refer to a Map key; whereas, 1 would refer to the value. If the map does not contain a value for a specific level the last generic will be used (e.g. a Map value).

      Nesting levels may also apply to array types; for example given String[], a nesting level of 2 refers to String.

      If a type does not contain generics the supertype hierarchy will be considered.

      Parameters:
      nestingLevel - the required nesting level, indexed from 1 for the current type, 2 for the first nested generic, 3 for the second and so on
      typeIndexesPerLevel - a map containing the generic index for a given nesting level (may be null)
      Returns:
      a ResolvableType for the nested level or NONE

    • getGeneric

      public ResolvableType getGeneric​(int... indexes)
      Return a ResolvableType representing the generic parameter for the given indexes. Indexes are zero based; for example given the type Map<Integer, List<String>>, getGeneric(0) will access the Integer. Nested generics can be accessed by specifying multiple indexes; for example getGeneric(1, 0) will access the String from the nested List. For convenience, if no indexes are specified the first generic is returned.

      If no generic is available at the specified indexes NONE is returned.

      Parameters:
      indexes - the indexes that refer to the generic parameter (may be omitted to return the first generic)
      Returns:
      a ResolvableType for the specified generic or NONE
      See Also:
      hasGenerics(), getGenerics(), resolveGeneric(int...), resolveGenerics()

    • getGenerics

      public ResolvableType[] getGenerics()
      Return an array of ResolvableTypes representing the generic parameters of this type. If no generics are available an empty array is returned. If you need to access a specific generic consider using the getGeneric(int...) method as it allows access to nested generics and protects against IndexOutOfBoundsExceptions.
      Returns:
      an array of ResolvableTypes representing the generic parameters (never null)
      See Also:
      hasGenerics(), getGeneric(int...), resolveGeneric(int...), resolveGenerics()

    • resolveGenerics

      public Class<?>[] resolveGenerics()
      Convenience method that will get and resolve generic parameters.
      Returns:
      an array of resolved generic parameters (the resulting array will never be null, but it may contain null elements})
      See Also:
      getGenerics(), resolve()

    • resolveGenerics

      public Class<?>[] resolveGenerics​(Class<?> fallback)
      Convenience method that will get and resolve generic parameters, using the specified fallback if any type cannot be resolved.
      Parameters:
      fallback - the fallback class to use if resolution fails (may be null)
      Returns:
      an array of resolved generic parameters (the resulting array will never be null, but it may contain null elements})
      See Also:
      getGenerics(), resolve()

    • resolveGeneric

      public Class<?> resolveGeneric​(int... indexes)
      Convenience method that will get and resolve a specific generic parameters.
      Parameters:
      indexes - the indexes that refer to the generic parameter (may be omitted to return the first generic)
      Returns:
      a resolved Class or null
      See Also:
      getGeneric(int...), resolve()

    • resolve

      public Class<?> resolve()
      Resolve this type to a Class, returning null if the type cannot be resolved. This method will consider bounds of TypeVariables and WildcardTypes if direct resolution fails; however, bounds of Object.class will be ignored.
      Returns:
      the resolved Class, or null if not resolvable
      See Also:
      resolve(Class), resolveGeneric(int...), resolveGenerics()

    • resolve

      public Class<?> resolve​(Class<?> fallback)
      Resolve this type to a Class, returning the specified fallback if the type cannot be resolved. This method will consider bounds of TypeVariables and WildcardTypes if direct resolution fails; however, bounds of Object.class will be ignored.
      Parameters:
      fallback - the fallback class to use if resolution fails (may be null)
      Returns:
      the resolved Class or the fallback
      See Also:
      resolve(), resolveGeneric(int...), resolveGenerics()

    • resolveType

      public ResolvableType resolveType()
      Resolve this type by a single level, returning the resolved value or NONE.

      Note: The returned ResolvableType should only be used as an intermediary as it cannot be serialized.

    • equals

      public boolean equals​(Object other)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Return a String representation of this type in its fully resolved form (including any generic parameters).
      Overrides:
      toString in class Object

    • forClass

      public static ResolvableType forClass​(Class<?> sourceClass)
      Return a ResolvableType for the specified Class, using the full generic type information for assignability checks. For example: ResolvableType.forClass(MyArrayList.class).
      Parameters:
      sourceClass - the source class (null is semantically equivalent to Object.class for typical use cases here}
      Returns:
      a ResolvableType for the specified class
      See Also:
      forClass(Class, Class), forClassWithGenerics(Class, Class...)

    • forRawClass

      public static ResolvableType forRawClass​(Class<?> sourceClass)
      Return a ResolvableType for the specified Class, doing assignability checks against the raw class only (analogous to Class.isAssignableFrom(java.lang.Class<?>), which this serves as a wrapper for. For example: ResolvableType.forClass(MyArrayList.class).
      Parameters:
      sourceClass - the source class (null is semantically equivalent to Object.class for typical use cases here}
      Returns:
      a ResolvableType for the specified class
      See Also:
      forClass(Class), getRawClass()

    • forClass

      public static ResolvableType forClass​(Class<?> sourceClass, Class<?> implementationClass)
      Return a ResolvableType for the specified Class with a given implementation. For example: ResolvableType.forClass(List.class, MyArrayList.class).
      Parameters:
      sourceClass - the source class (must not be null
      implementationClass - the implementation class
      Returns:
      a ResolvableType for the specified class backed by the given implementation class
      See Also:
      forClass(Class), forClassWithGenerics(Class, Class...)

    • forClassWithGenerics

      public static ResolvableType forClassWithGenerics​(Class<?> sourceClass, Class<?>... generics)
      Return a ResolvableType for the specified Class with pre-declared generics.
      Parameters:
      sourceClass - the source class
      generics - the generics of the class
      Returns:
      a ResolvableType for the specific class and generics
      See Also:
      forClassWithGenerics(Class, ResolvableType...)

    • forClassWithGenerics

      public static ResolvableType forClassWithGenerics​(Class<?> sourceClass, ResolvableType... generics)
      Return a ResolvableType for the specified Class with pre-declared generics.
      Parameters:
      sourceClass - the source class
      generics - the generics of the class
      Returns:
      a ResolvableType for the specific class and generics
      See Also:
      forClassWithGenerics(Class, Class...)

    • forMethodReturnType

      public static ResolvableType forMethodReturnType​(Method method)
      Return a ResolvableType for the specified Method return type.
      Parameters:
      method - the source for the method return type
      Returns:
      a ResolvableType for the specified method return
      See Also:
      forMethodReturnType(Method, Class)

    • forMethodReturnType

      public static ResolvableType forMethodReturnType​(Method method, Class<?> implementationClass)
      Return a ResolvableType for the specified Method return type. Use this variant when the class that declares the method includes generic parameter variables that are satisfied by the implementation class.
      Parameters:
      method - the source for the method return type
      implementationClass - the implementation class
      Returns:
      a ResolvableType for the specified method return
      See Also:
      forMethodReturnType(Method)

    • forMethodParameter

      public static ResolvableType forMethodParameter​(Method method, int parameterIndex)
      Return a ResolvableType for the specified Method parameter.
      Parameters:
      method - the source method (must not be null)
      parameterIndex - the parameter index
      Returns:
      a ResolvableType for the specified method parameter
      See Also:
      forMethodParameter(Method, int, Class), forMethodParameter(MethodParameter)

    • forMethodParameter

      public static ResolvableType forMethodParameter​(Method method, int parameterIndex, Class<?> implementationClass)
      Return a ResolvableType for the specified Method parameter with a given implementation. Use this variant when the class that declares the method includes generic parameter variables that are satisfied by the implementation class.
      Parameters:
      method - the source method (must not be null)
      parameterIndex - the parameter index
      implementationClass - the implementation class
      Returns:
      a ResolvableType for the specified method parameter
      See Also:
      forMethodParameter(Method, int, Class), forMethodParameter(MethodParameter)

    • forMethodParameter

      public static ResolvableType forMethodParameter​(MethodParameter methodParameter)
      Return a ResolvableType for the specified MethodParameter.
      Parameters:
      methodParameter - the source method parameter (must not be null)
      Returns:
      a ResolvableType for the specified method parameter
      See Also:
      forMethodParameter(Method, int)

    • forMethodParameter

      public static ResolvableType forMethodParameter​(MethodParameter methodParameter, ResolvableType implementationType)
      Return a ResolvableType for the specified MethodParameter with a given implementation type. Use this variant when the class that declares the method includes generic parameter variables that are satisfied by the implementation type.
      Parameters:
      methodParameter - the source method parameter (must not be null)
      implementationType - the implementation type
      Returns:
      a ResolvableType for the specified method parameter
      See Also:
      forMethodParameter(MethodParameter)

    • forMethodParameter

      public static ResolvableType forMethodParameter​(MethodParameter methodParameter, Type targetType)
      Return a ResolvableType for the specified MethodParameter, overriding the target type to resolve with a specific given type.
      Parameters:
      methodParameter - the source method parameter (must not be null)
      targetType - the type to resolve (a part of the method parameter's type)
      Returns:
      a ResolvableType for the specified method parameter
      See Also:
      forMethodParameter(Method, int)

    • forArrayComponent

      public static ResolvableType forArrayComponent​(ResolvableType componentType)
      Return a ResolvableType as a array of the specified componentType.
      Parameters:
      componentType - the component type
      Returns:
      a ResolvableType as an array of the specified component type

    • forType

      public static ResolvableType forType​(Type type)
      Return a ResolvableType for the specified Type. Note: The resulting ResolvableType may not be Serializable.
      Parameters:
      type - the source type or null
      Returns:
      a ResolvableType for the specified Type
      See Also:
      forType(Type, ResolvableType)

    • forType

      public static ResolvableType forType​(Type type, ResolvableType owner)
      Return a ResolvableType for the specified Type backed by the given owner type. Note: The resulting ResolvableType may not be Serializable.
      Parameters:
      type - the source type or null
      owner - the owner type used to resolve variables
      Returns:
      a ResolvableType for the specified Type and owner
      See Also:
      forType(Type)

    • forType

      public static ResolvableType forType​(Type type, ResolvableType.VariableResolver variableResolver)
      Return a ResolvableType for the specified Type backed by a given ResolvableType.VariableResolver.
      Parameters:
      type - the source type or null
      variableResolver - the variable resolver or null
      Returns:
      a ResolvableType for the specified Type and ResolvableType.VariableResolver