/**
* Copyright (C) 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.inject.util;
import com.google.inject.Provider;
import com.google.inject.internal.MoreTypes;
import com.google.inject.internal.MoreTypes.GenericArrayTypeImpl;
import com.google.inject.internal.MoreTypes.ParameterizedTypeImpl;
import com.google.inject.internal.MoreTypes.WildcardTypeImpl;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Static methods for working with types.
*
* @author crazybob@google.com (Bob Lee)
* @since 2.0
*/
public final class Types {
private Types() {}
/**
* Returns a new parameterized type, applying {@code typeArguments} to
* {@code rawType}. The returned type does not have an owner type.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType newParameterizedType(Type rawType, Type... typeArguments) {
return newParameterizedTypeWithOwner(null, rawType, typeArguments);
}
/**
* Returns a new parameterized type, applying {@code typeArguments} to
* {@code rawType} and enclosed by {@code ownerType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType newParameterizedTypeWithOwner(
Type ownerType, Type rawType, Type... typeArguments) {
return new ParameterizedTypeImpl(ownerType, rawType, typeArguments);
}
/**
* Returns an array type whose elements are all instances of
* {@code componentType}.
*
* @return a {@link java.io.Serializable serializable} generic array type.
*/
public static GenericArrayType arrayOf(Type componentType) {
return new GenericArrayTypeImpl(componentType);
}
/**
* Returns a type that represents an unknown type that extends {@code bound}.
*/
public static WildcardType subtypeOf(Type bound) {
return new WildcardTypeImpl(new Type[] { bound }, MoreTypes.EMPTY_TYPE_ARRAY);
}
/**
* Returns a type that represents an unknown supertype of {@code bound}.
*/
public static WildcardType supertypeOf(Type bound) {
return new WildcardTypeImpl(new Type[] { Object.class }, new Type[] { bound });
}
/**
* Returns a type modelling a {@link List} whose elements are of type
* {@code elementType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType listOf(Type elementType) {
return newParameterizedType(List.class, elementType);
}
/**
* Returns a type modelling a {@link Set} whose elements are of type
* {@code elementType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType setOf(Type elementType) {
return newParameterizedType(Set.class, elementType);
}
/**
* Returns a type modelling a {@link Map} whose keys are of type
* {@code keyType} and whose values are of type {@code valueType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType mapOf(Type keyType, Type valueType) {
return newParameterizedType(Map.class, keyType, valueType);
}
// for other custom collections types, use newParameterizedType()
/**
* Returns a type modelling a {@link Provider} that provides elements of type
* {@code elementType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType providerOf(Type providedType) {
return newParameterizedType(Provider.class, providedType);
}
}