org.jeesy.classinfo

Class TypeInfo<T>

java.lang.Object

org.jeesy.classinfo.TypeInfo<T>

public class TypeInfo<T>
extends Object

Represents a generic type T. Java doesn't yet provide a way to represent generic types, so this class does. Forces clients to create a subclass of this class which enables retrieval the type information even at runtime.

For example, to create a type literal for List<String>, you can create an empty anonymous inner class:

TypeInfo<List<String>> list = new TypeInfo<List<String>>() {};

Along with modeling generic types, this class can resolve type parameters. For example, to figure out what type keySet() returns on a Map<Integer, String>, use this code:

   TypeInfo<Map<Integer, String>> mapType
       = new TypeInfo<Map<Integer, String>>() {};
   TypeInfo<?> keySetType
       = mapType.getReturnType(Map.class.getMethod("keySet"));
   System.out.println(keySetType); // prints "Set<Integer>"

Author:

crazybob@google.com (Bob Lee), jessewilson@google.com (Jesse Wilson) //size: header + 4*4 = 24b

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TypeInfo() Constructs a new type literal.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o)
static <T> TypeInfo<T>	forClass(Class<T> type) Create new type info for given Type
static <T> TypeInfo<T>	forClass(Class<T> type, AnnotatedNode annotatedNode) Create new type info for given Type
static TypeInfo<?>	forType(Type type) Create new type info for given Type
static TypeInfo<?>	forType(Type type, AnnotatedNode annotatedNode) Create new type info for given Type
AnnotatedNode	getAnnotatedNode()
TypeInfo<?>	getComponentType()
List<TypeInfo<?>>	getExceptionTypes(Member methodOrConstructor) Returns the resolved generic exception types thrown by constructor.
TypeInfo<?>	getFieldType(Field field) Returns the resolved generic type of field.
TypeInfo[]	getInterfaces()
List<TypeInfo<?>>	getParameterTypes(Member methodOrConstructor) Returns the resolved generic parameter types of methodOrConstructor.
Class<T>	getRawType() Returns the raw (non-generic) type for this type.
TypeInfo<?>	getReturnType(Method method) Returns the resolved generic return type of method.
TypeInfo<?>	getSuperType()
TypeInfo<?>	getSupertype(Class<?> supertype) Returns the generic form of supertype.
Type	getType() Gets underlying Type instance.
int	hashCode()
boolean	hasParameters()
boolean	isArray()
protected TypeInfo	resolveForClass(Class _type)
TypeInfo	resolveParameter(int index)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TypeInfo

protected TypeInfo()

Constructs a new type literal. Derives represented class from type parameter.

Clients create an empty anonymous subclass. Doing so embeds the type parameter in the anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.

Method Detail

getAnnotatedNode

public AnnotatedNode getAnnotatedNode()

getRawType

public final Class<T> getRawType()

Returns the raw (non-generic) type for this type.

Since:

2.0

getType

public final Type getType()

Gets underlying Type instance.

hashCode

public final int hashCode()

Overrides:

hashCode in class Object

equals

public final boolean equals(Object o)

Overrides:

equals in class Object

toString

public final String toString()

Overrides:

toString in class Object

getComponentType

public TypeInfo<?> getComponentType()

isArray

public boolean isArray()

getSuperType

public TypeInfo<?> getSuperType()

getInterfaces

public TypeInfo[] getInterfaces()

hasParameters

public boolean hasParameters()

resolveParameter

public TypeInfo resolveParameter(int index)

resolveForClass

protected TypeInfo resolveForClass(Class _type)

forType

public static TypeInfo<?> forType(Type type)

Create new type info for given Type

forType

public static TypeInfo<?> forType(Type type,
                  AnnotatedNode annotatedNode)

Create new type info for given Type

forClass

public static <T> TypeInfo<T> forClass(Class<T> type)

Create new type info for given Type

forClass

public static <T> TypeInfo<T> forClass(Class<T> type,
                       AnnotatedNode annotatedNode)

Create new type info for given Type

getSupertype

public TypeInfo<?> getSupertype(Class<?> supertype)

Returns the generic form of supertype. For example, if this is ArrayList<String>, this returns Iterable<String> given the input Iterable.class.

Parameters:

supertype - a superclass of, or interface implemented by, this.

Since:

2.0

getFieldType

public TypeInfo<?> getFieldType(Field field)

Returns the resolved generic type of field.

Parameters:

field - a field defined by this or any superclass.

Since:

2.0

getParameterTypes

public List<TypeInfo<?>> getParameterTypes(Member methodOrConstructor)

Returns the resolved generic parameter types of methodOrConstructor.

Parameters:

methodOrConstructor - a method or constructor defined by this or any supertype.

Since:

2.0

getExceptionTypes

public List<TypeInfo<?>> getExceptionTypes(Member methodOrConstructor)

Returns the resolved generic exception types thrown by constructor.

Parameters:

methodOrConstructor - a method or constructor defined by this or any supertype.

Since:

2.0

getReturnType

public TypeInfo<?> getReturnType(Method method)

Returns the resolved generic return type of method.

Parameters:

method - a method defined by this or any supertype.

Since:

2.0