| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.tamaya; |
| |
| import java.io.Serializable; |
| import java.lang.reflect.GenericArrayType; |
| import java.lang.reflect.ParameterizedType; |
| import java.lang.reflect.Type; |
| import java.util.Objects; |
| |
| |
| /** |
| * <p>Class for instantiation of objects that represent parameterized types |
| * with current parameters.</p> |
| * |
| * <p>An createObject that represents a parameterized type may be obtained by |
| * subclassing {@link TypeLiteral}.</p> |
| * |
| * <pre> |
| * TypeLiteral<List<Integer>> stringListType = new TypeLiteral<List<Integer>>() {}; |
| * </pre> |
| * |
| * @param <T> the type, including all type parameters |
| */ |
| public class TypeLiteral<T> implements Serializable { |
| |
| private static final long serialVersionUID = 1L; |
| private static final Type[] EMPTY_TYPE_ARRAY = new Type[0]; |
| /** The current defined type. */ |
| private final Type definedType; |
| |
| /** |
| * Constructor. |
| * @param definedType the defined type. |
| */ |
| public TypeLiteral(Type definedType) { |
| Objects.requireNonNull(definedType, "Type must be given"); |
| |
| this.definedType = definedType; |
| } |
| |
| /** |
| * Constructor only for directly implementing a TypeLiteral hereby dynamically implementing a generic interface. |
| */ |
| public TypeLiteral() { |
| this.definedType = getDefinedType(this.getClass()); |
| } |
| |
| /** |
| * Creates a new TypeLiteral based on a given type. |
| * |
| * @param type the type, not {@code null}. |
| * @param <R> the literal generic type. |
| * @return the corresponding TypeLiteral, never {@code null}. |
| */ |
| public static <R> TypeLiteral<R> of(Type type) { |
| Objects.requireNonNull(type, "Type must be given."); |
| |
| return new TypeLiteral<>(type); |
| } |
| |
| /** |
| * Checks the current implemented generic interfaces and evaluates the given single type parameter. |
| * |
| * @param clazz the class to check, not {@code null}. |
| * @param interfaceType the interface type to be checked, not {@code null}. |
| * @return the generic type parameters, or an empty array, if it cannot be evaluated. |
| */ |
| public static Type[] getGenericInterfaceTypeParameters(Class<?> clazz, Class<?> interfaceType) { |
| Objects.requireNonNull(clazz, "Class parameter must be given."); |
| Objects.requireNonNull(interfaceType, "Interface parameter must be given."); |
| |
| for (Type type : clazz.getGenericInterfaces()) { |
| if (type instanceof ParameterizedType) { |
| ParameterizedType parameterizedType = (ParameterizedType) type; |
| if(parameterizedType.getRawType().equals(interfaceType)){ |
| return parameterizedType.getActualTypeArguments(); |
| } |
| } |
| } |
| return EMPTY_TYPE_ARRAY; |
| } |
| |
| /** |
| * Method that checks the class's type for a generic interface implementation type. |
| * |
| * @param type the type, not {@code null}. |
| * @return the generic type parameter of the given single type generic interfaceType, or an empty array. |
| */ |
| public static Type[] getTypeParameters(Type type) { |
| Objects.requireNonNull(type, "Type must be given."); |
| |
| if (type instanceof ParameterizedType) { |
| ParameterizedType parameterizedType = (ParameterizedType) type; |
| return parameterizedType.getActualTypeArguments(); |
| } |
| return EMPTY_TYPE_ARRAY; |
| } |
| |
| public final Type getType() { |
| return definedType; |
| } |
| |
| /** |
| * Returns basic raw Java type. |
| * |
| * @return the actual type represented by this createObject |
| */ |
| @SuppressWarnings("unchecked") |
| public final Class<T> getRawType() { |
| Class<T> rawType; |
| |
| if (this.definedType instanceof ParameterizedType) { |
| ParameterizedType pt = (ParameterizedType) this.definedType; |
| rawType = (Class<T>) pt.getRawType(); |
| } else if (this.definedType instanceof GenericArrayType) { |
| rawType = (Class<T>) Object[].class; |
| } else if (this.definedType instanceof Class) { |
| rawType = (Class<T>) this.definedType; |
| } else { |
| throw new RuntimeException("Illegal type for the Type Literal Class"); |
| } |
| |
| return rawType; |
| } |
| |
| |
| protected Type getDefinedType(Class<?> clazz) { |
| Type type; |
| |
| if (clazz == null) { |
| throw new RuntimeException("Class parameter clazz can not be null"); |
| } |
| |
| Type superClazz = clazz.getGenericSuperclass(); |
| |
| if (superClazz instanceof ParameterizedType) { |
| ParameterizedType pt = (ParameterizedType) superClazz; |
| Type[] actualArgs = pt.getActualTypeArguments(); |
| |
| if (actualArgs.length == 1) { |
| type = actualArgs[0]; |
| |
| } else { |
| throw new RuntimeException("More than one parametric type"); |
| } |
| |
| } else if (superClazz.equals(Object.class)) { |
| throw new RuntimeException("Super class must be parametrized type"); |
| } else { |
| type = getDefinedType((Class<?>) superClazz); |
| } |
| |
| return type; |
| } |
| |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = 1; |
| result = prime * result + ((definedType == null) ? 0 : definedType.hashCode()); |
| return result; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (obj == null) { |
| return false; |
| } |
| if (getClass() != obj.getClass()) { |
| return false; |
| } |
| TypeLiteral<?> other = (TypeLiteral<?>) obj; |
| if (definedType == null) { |
| if (other.definedType != null) { |
| return false; |
| } |
| } else if (!definedType.equals(other.definedType)) { |
| return false; |
| } |
| return true; |
| } |
| |
| |
| @Override |
| public String toString() { |
| return "TypeLiteral{" + |
| "type=" + definedType + |
| '}'; |
| } |
| |
| } |