Top Description Fields Constructors Methods
javax.ws.rs.core

public Class GenericType<T>

extends Object
Class Inheritance
Type Parameters
<T>
the generic type parameter.
Imports
java.lang.reflect.Array, .GenericArrayType, .ParameterizedType, .Type, .TypeVariable, java.util.Arrays, .Stack
Represents a generic message entity type T. Supports in-line instantiation of objects that represent generic types with actual type parameters. An object that represents any parameterized type may be obtained by sub-classing GenericType. Alternatively, an object representing a concrete parameterized type can be created using a GenericType(java.lang.reflect.Type) and manually specifying the actual (parameterized) type.

For example: 

 GenericType<List<String>> stringListType = new GenericType<List<String>>() {};

Or: 

 public class MyGenericType extends GenericType<List<String>> { ... }

 ...

 MyGenericType stringListType = new MyGenericType();

Note that due to the Java type erasure limitations the parameterized type information must be specified on a subclass, not just during the instance creation. For example, the following case would throw an IllegalArgumentException: 

 public class MyGenericType<T> extends GenericType<T> { ... }

 ...

 // The type is only specified on instance, not in a sub-class
 MyGenericType<List<String>> stringListType =
         new MyGenericType<List<String>>();
Authors
Marek Potociar, Paul Sandoz, Martin Matula
Since
2.0

Field Summary

Modifier and TypeField and Description
private final Class<?>
rawType

The actual raw parameter type.

private final Type
type

Type represented by the generic type instance.

Constructor Summary

AccessConstructor and Description
protected
GenericType()

Constructs a new generic type, deriving the generic type and class from type parameter.

public
GenericType(Type
the generic type.
genericType)

Constructs a new generic type, supplying the generic type information and deriving the class.

Method Summary

Modifier and TypeMethod and Description
public boolean
equals(Object
the reference object with which to compare.
obj)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.
public static GenericType<T>

Returns:

GenericType describing the Java instance.
forInstance(final Object
Java instance for which the GenericType description should be created.
instance)

Create a generic type from a Java instance.

private static Class<T>

Returns:

the array class.
getArrayClass(Class<T>
the component class of the array
c)

Get Array class of component class.

private static Class<T>

Returns:

the class or interface that declared the supplied type.
getClass(Type
Type to inspect.
type)

Returns the object representing the class or interface that declared the supplied type.

public final Class<?>

Returns:

the class or interface that declared the type represented by this generic type instance.
getRawType()

Returns the object representing the class or interface that declared the type represented by this generic type instance.

public final Type

Returns:

the actual type represented by this generic type instance.
getType()

Retrieve the type represented by the generic type instance.

pack-priv static Type

Returns:

the parameterized type of GenericType<T> (aka T)
getTypeArgument(Class<?>
subClass of baseClass to analyze.
clazz, Class<?>
base class having the type parameter the value of which we need to retrieve
baseClass)

Return the value of the type parameter of GenericType<T>.

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for the object.
public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.
Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

rawTypeback to summary
private final Class<?> rawType

The actual raw parameter type.

typeback to summary
private final Type type

Type represented by the generic type instance.

Constructor Detail

GenericTypeback to summary
protected GenericType()

Constructs a new generic type, deriving the generic type and class from type parameter. Note that this constructor is protected, users should create a (usually anonymous) subclass as shown above.

Exceptions
IllegalArgumentException:
in case the generic type parameter value is not provided by any of the subclasses.
GenericTypeback to summary
public GenericType(Type genericType)

Constructs a new generic type, supplying the generic type information and deriving the class.

Parameters
genericType:Type

the generic type.

Exceptions
IllegalArgumentException:
if genericType is null or not an instance of Class or ParameterizedType whose raw type is an instance of Class.

Method Detail

equalsback to summary
public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
obj:Object

the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations
@Override
forInstanceback to summary
public static GenericType<T> forInstance(final Object instance)

Create a generic type from a Java instance.

If the supplied instance is a javax.ws.rs.core.GenericEntity, the generic type will be computed using the javax.ws.rs.core.GenericEntity#getType(). Otherwise instance.getClass() will be used.

Parameters
instance:Object

Java instance for which the GenericType description should be created.

Returns:GenericType<T>

GenericType describing the Java instance.

Since
2.1
getArrayClassback to summary
private static Class<T> getArrayClass(Class<T> c)

Get Array class of component class.

Parameters
c:Class<T>

the component class of the array

Returns:Class<T>

the array class.

getClassback to summary
private static Class<T> getClass(Type type)

Returns the object representing the class or interface that declared the supplied type.

Parameters
type:Type

Type to inspect.

Returns:Class<T>

the class or interface that declared the supplied type.

getRawTypeback to summary
public final Class<?> getRawType()

Returns the object representing the class or interface that declared the type represented by this generic type instance.

Returns:Class<?>

the class or interface that declared the type represented by this generic type instance.

getTypeback to summary
public final Type getType()

Retrieve the type represented by the generic type instance.

Returns:Type

the actual type represented by this generic type instance.

getTypeArgumentback to summary
pack-priv static Type getTypeArgument(Class<?> clazz, Class<?> baseClass)

Return the value of the type parameter of GenericType<T>.

Parameters
clazz:Class<?>

subClass of baseClass to analyze.

baseClass:Class<?>

base class having the type parameter the value of which we need to retrieve

Returns:Type

the parameterized type of GenericType<T> (aka T)

hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object.

Annotations
@Override
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations
@Override