Package: org.codehaus.groovy.ast.tools

## [Java] Class GenericsUtils

- org.codehaus.groovy.ast.tools.GenericsUtils

- Utility methods to deal with generic types.

- - ### Field Summary

    Fields
    Modifiers | Name | Description
    --- | --- | ---
    `static GenericsType[]` | `EMPTY_GENERICS_ARRAY` |
    `static String` | `JAVA_LANG_OBJECT` |

  - ### Methods Summary

    Methods
    Type Params | Return Type | Name and description
    --- | --- | ---
    `` | `void` | `addError(String msg, ASTNode expr)`
    `` | `static Map<String, ClassNode>` | `addMethodGenerics(MethodNode current, Map<String, ClassNode> oldSpec)`
    `` | `static GenericsType[]` | `alignGenericTypes(GenericsType[] redirectGenericTypes, GenericsType[] parameterizedTypes, GenericsType[] alignmentTarget)` Given a parameterized type and a generic type information, aligns actual type parameters.
    `` | `static GenericsType[]` | `applyGenericsContextToPlaceHolders(Map<String, ClassNode> genericsSpec, GenericsType[] oldPlaceHolders)` Transforms generics types from an old context to a new context using the given spec.
    `` | `static GenericsType` | `buildWildcardType(ClassNode types)` Generates a wildcard generic type in order to be used for checks against class nodes.
    `` | `static void` | `clearParameterizedTypeCache()` Clear the parameterized type cache It is useful to IDE as the type being compiled are continuously being edited/altered, see GROOVY-8675
    `` | `static MethodNode` | `correctToGenericsSpec(Map<String, ClassNode> genericsSpec, MethodNode mn)`
    `` | `static ClassNode` | `correctToGenericsSpec(Map<String, ClassNode> genericsSpec, GenericsType type)`
    `` | `static ClassNode` | `correctToGenericsSpec(Map<String, ClassNode> genericsSpec, ClassNode type)`
    `` | `static ClassNode` | `correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode type)`
    `` | `static ClassNode[]` | `correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode[] types)` Since: 2.4.1
    `` | `static ClassNode` | `correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode type, List<String> exclusions)`
    `` | `static Map<String, ClassNode>` | `createGenericsSpec(ClassNode current)`
    `` | `static Map<String, ClassNode>` | `createGenericsSpec(ClassNode current, Map<String, ClassNode> oldSpec)`
    `` | `static Map<GenericsType.GenericsTypeName, GenericsType>` | `extractPlaceholders(ClassNode cn)`
    `` | `static void` | `extractPlaceholders(ClassNode node, Map<GenericsType.GenericsTypeName, GenericsType> map)` For a given classnode, fills in the supplied map with the parameterized types it defines.
    `` | `static void` | `extractSuperClassGenerics(ClassNode type, ClassNode target, Map<String, ClassNode> spec)`
    `` | `static ClassNode` | `findActualTypeByGenericsPlaceholderName(String placeholderName, Map<GenericsType, GenericsType> genericsPlaceholderAndTypeMap)` Gets the actual type according to the placeholder name.
    `` | `static ClassNode` | `findParameterizedType(ClassNode genericsClass, ClassNode actualType, boolean tryToFindExactType)` Get the parameterized type by search the whole class hierarchy according to generics class and actual receiver.
    `` | `static ClassNode` | `findParameterizedTypeFromCache(ClassNode genericsClass, ClassNode actualType, boolean tryToFindExactType)` Try to get the parameterized type from the cache.
    `` | `static ClassNode` | `getSuperClass(ClassNode type, ClassNode target)`
    `` | `static boolean` | `hasNonPlaceHolders(ClassNode parameterizedType)` Check whether the ClassNode has non generics placeholders, aka not placeholder
    `` | `static boolean` | `hasPlaceHolders(ClassNode parameterizedType)` Check whether the ClassNode has generics placeholders
    `` | `static ClassNode` | `makeClassSafe(Class klass)`
    `` | `static ClassNode` | `makeClassSafe0(ClassNode type, GenericsType genericTypes)`
    `` | `static ClassNode` | `makeClassSafeWithGenerics(Class klass, ClassNode genericsType)`
    `` | `static ClassNode` | `makeClassSafeWithGenerics(ClassNode type, GenericsType genericTypes)`
    `` | `static Map<GenericsType, GenericsType>` | `makeDeclaringAndActualGenericsTypeMap(ClassNode declaringClass, ClassNode actualReceiver)` map declaring generics type to actual generics type, e.g.
    `` | `static Map<GenericsType, GenericsType>` | `makeDeclaringAndActualGenericsTypeMapOfExactType(ClassNode declaringClass, ClassNode actualReceiver)` The method is similar with GenericsUtils.makeDeclaringAndActualGenericsTypeMap, The main difference is that the method will try to map all placeholders found to the relevant exact types, but the other will not try even if the parameterized type has placeholders
    `` | `static ClassNode` | `newClass(ClassNode type)`
    `` | `static ClassNode` | `nonGeneric(ClassNode type)`
    `` | `static ClassNode` | `parameterizeInterfaceGenerics(ClassNode hint, ClassNode target)` Interface class nodes retrieved from ClassNode.getInterfaces or ClassNode.getAllInterfaces are returned with generic type arguments.
    `` | `static Tuple2<ClassNode, ClassNode>` | `parameterizeSAM(ClassNode samType)` Gets the parameter and return types of the abstract method of SAM.
    `` | `static ClassNode` | `parameterizeType(ClassNode hint, ClassNode target)` Interface class nodes retrieved from ClassNode.getInterfaces or ClassNode.getAllInterfaces are returned with generic type arguments.
    `` | `static ClassNode[]` | `parseClassNodesFromString(String option, SourceUnit sourceUnit, CompilationUnit compilationUnit, MethodNode mn, ASTNode usage)`
    `` | `static String` | `toGenericTypesString(GenericsType[] genericsTypes)`

  - ### Inherited Methods Summary

    Inherited Methods
    Methods inherited from class | Name
    --- | ---
    `class Object` | `wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll`

- - ### Field Detail

    - #### public static final GenericsType[] EMPTY_GENERICS_ARRAY

    - #### public static final String JAVA_LANG_OBJECT

  - ### Method Detail

    - #### @com.github.javaparser.ast.expr.MarkerAnnotationExprOverride public void addError(String msg, ASTNode expr)

    - #### public static Map<String, ClassNode> addMethodGenerics(MethodNode current, Map<String, ClassNode> oldSpec)

    - #### @com.github.javaparser.ast.expr.MarkerAnnotationExprDeprecated public static GenericsType[] alignGenericTypes(GenericsType[] redirectGenericTypes, GenericsType[] parameterizedTypes, GenericsType[] alignmentTarget)

      Given a parameterized type and a generic type information, aligns actual type parameters. For example, if a class uses generic type

          <T,U,V>

      (redirectGenericTypes), is used with actual type parameters

          <java.lang.String, U,V>

      , then a class or interface using generic types

          <T,V>

      will be aligned to

          <java.lang.String,V>

      deprecated:
        You shouldn't call this method because it is inherently unreliable
      Parameters:
        `redirectGenericTypes` - the type arguments or the redirect class node
        `parameterizedTypes` - the actual type arguments used on this class node
        `alignmentTarget` - the generic type arguments to which we want to align to
      Returns:
        aligned type arguments

    - #### public static GenericsType[] applyGenericsContextToPlaceHolders(Map<String, ClassNode> genericsSpec, GenericsType[] oldPlaceHolders)

      Transforms generics types from an old context to a new context using the given spec. This method assumes all generics types will be placeholders. WARNING: The resulting generics types may or may not be placeholders after the transformation.

      Parameters:
        `genericsSpec` - the generics context information spec
        `oldPlaceHolders` - the old placeholders
      Returns:
        the new generics types

    - #### public static GenericsType buildWildcardType(ClassNode types)

      Generates a wildcard generic type in order to be used for checks against class nodes. See GenericsType#isCompatibleWith(org.codehaus.groovy.ast.ClassNode).

      Parameters:
        `types` - the type to be used as the wildcard upper bound
      Returns:
        a wildcard generics type

    - #### public static void clearParameterizedTypeCache()

      Clear the parameterized type cache It is useful to IDE as the type being compiled are continuously being edited/altered, see GROOVY-8675

    - #### public static MethodNode correctToGenericsSpec(Map<String, ClassNode> genericsSpec, MethodNode mn)

    - #### public static ClassNode correctToGenericsSpec(Map<String, ClassNode> genericsSpec, GenericsType type)

    - #### public static ClassNode correctToGenericsSpec(Map<String, ClassNode> genericsSpec, ClassNode type)

    - #### public static ClassNode correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode type)

    - #### public static ClassNode[] correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode[] types)

      Since:
        2.4.1

    - #### public static ClassNode correctToGenericsSpecRecurse(Map<String, ClassNode> genericsSpec, ClassNode type, List<String> exclusions)

    - #### public static Map<String, ClassNode> createGenericsSpec(ClassNode current)

    - #### public static Map<String, ClassNode> createGenericsSpec(ClassNode current, Map<String, ClassNode> oldSpec)

    - #### public static Map<GenericsType.GenericsTypeName, GenericsType> extractPlaceholders(ClassNode cn)

    - #### public static void extractPlaceholders(ClassNode node, Map<GenericsType.GenericsTypeName, GenericsType> map)

      For a given classnode, fills in the supplied map with the parameterized types it defines.

      Parameters:
        `node` - the class node to check
        `map` - the generics type information collector

    - #### public static void extractSuperClassGenerics(ClassNode type, ClassNode target, Map<String, ClassNode> spec)

    - #### public static ClassNode findActualTypeByGenericsPlaceholderName(String placeholderName, Map<GenericsType, GenericsType> genericsPlaceholderAndTypeMap)

      Gets the actual type according to the placeholder name.

      Parameters:
        `placeholderName` - the placeholder name (i.e. "T", "E", etc.)
        `genericsPlaceholderAndTypeMap` - the result of makeDeclaringAndActualGenericsTypeMap(ClassNode, ClassNode)

    - #### public static ClassNode findParameterizedType(ClassNode genericsClass, ClassNode actualType, boolean tryToFindExactType)

      Get the parameterized type by search the whole class hierarchy according to generics class and actual receiver. findParameterizedTypeFromCache(ClassNode, ClassNode, boolean) is strongly recommended for better performance.

      Parameters:
        `genericsClass` - the generics class
        `actualType` - the actual type
        `tryToFindExactType` - whether to try to find exact type
      Returns:
        the parameterized type

    - #### public static ClassNode findParameterizedTypeFromCache(ClassNode genericsClass, ClassNode actualType, boolean tryToFindExactType)

      Try to get the parameterized type from the cache. If no cached item found, cache and return the result of findParameterizedType(ClassNode, ClassNode, boolean)

    - #### public static ClassNode getSuperClass(ClassNode type, ClassNode target)

    - #### public static boolean hasNonPlaceHolders(ClassNode parameterizedType)

      Check whether the ClassNode has non generics placeholders, aka not placeholder

      Parameters:
        `parameterizedType` - the class node
      Returns:
        the result
      Since:
        3.0.0

    - #### public static boolean hasPlaceHolders(ClassNode parameterizedType)

      Check whether the ClassNode has generics placeholders

      Parameters:
        `parameterizedType` - the class node
      Returns:
        the result
      Since:
        3.0.0

    - #### public static ClassNode makeClassSafe(Class klass)

    - #### public static ClassNode makeClassSafe0(ClassNode type, GenericsType genericTypes)

    - #### public static ClassNode makeClassSafeWithGenerics(Class klass, ClassNode genericsType)

    - #### public static ClassNode makeClassSafeWithGenerics(ClassNode type, GenericsType genericTypes)

    - #### public static Map<GenericsType, GenericsType> makeDeclaringAndActualGenericsTypeMap(ClassNode declaringClass, ClassNode actualReceiver)

      map declaring generics type to actual generics type, e.g. GROOVY-7204: declaring generics types: T, S extends Serializable actual generics types : String, Long the result map is [ T: String, S: Long ] The resolved types can not help us to choose methods correctly if the argument is a string: T: Object, S: Serializable so we need actual types: T: String, S: Long

    - #### public static Map<GenericsType, GenericsType> makeDeclaringAndActualGenericsTypeMapOfExactType(ClassNode declaringClass, ClassNode actualReceiver)

      The method is similar with GenericsUtils.makeDeclaringAndActualGenericsTypeMap, The main difference is that the method will try to map all placeholders found to the relevant exact types, but the other will not try even if the parameterized type has placeholders

      Parameters:
        `declaringClass` - the generics class node declaring the generics types
        `actualReceiver` - the sub-class class node
      Returns:
        the placeholder-to-actualtype mapping
      Since:
        3.0.0

    - #### public static ClassNode newClass(ClassNode type)

    - #### public static ClassNode nonGeneric(ClassNode type)

    - #### @com.github.javaparser.ast.expr.MarkerAnnotationExprDeprecated public static ClassNode parameterizeInterfaceGenerics(ClassNode hint, ClassNode target)

      Interface class nodes retrieved from ClassNode.getInterfaces or ClassNode.getAllInterfaces are returned with generic type arguments. This method allows returning a parameterized interface given the parameterized class node which implements this interface.

      deprecated:
        Use #parameterizeType instead
      Parameters:
        `hint` - the class node where generics types are parameterized
        `target` - the interface we want to parameterize generics types
      Returns:
        a parameterized interface class node

    - #### public static Tuple2<ClassNode, ClassNode> parameterizeSAM(ClassNode samType)

      Gets the parameter and return types of the abstract method of SAM. If the abstract method is not parameterized, we will get generics placeholders, e.g. T, U For example, the abstract method of Function is

                R apply(T t);

      We parameterize the above interface as `Function<String, Integer>`, then the abstract method will be

                Integer apply(String t);

      When we call `parameterizeSAM` on the ClassNode `Function<String, Integer>`, we can get parameter types and return type of the above abstract method, i.e. ClassNode `ClassHelper.STRING_TYPE` and `ClassHelper.Integer_TYPE`
      Parameters:
        `samType` - the class node which contains only one abstract method
      Since:
        3.0.0

    - #### public static ClassNode parameterizeType(ClassNode hint, ClassNode target)

      Interface class nodes retrieved from ClassNode.getInterfaces or ClassNode.getAllInterfaces are returned with generic type arguments. This method allows returning a parameterized interface given the parameterized class node which implements this interface.

      Parameters:
        `hint` - the class node where generics types are parameterized
        `target` - the interface we want to parameterize generics types
      Returns:
        a parameterized interface class node

    - #### public static ClassNode[] parseClassNodesFromString(String option, SourceUnit sourceUnit, CompilationUnit compilationUnit, MethodNode mn, ASTNode usage)

    - #### public static String toGenericTypesString(GenericsType[] genericsTypes)