| /* |
| * Copyright (c) OSGi Alliance (2008, 2009). All Rights Reserved. |
| * |
| * 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 org.apache.felix.gogo.commands.converter; |
| |
| /** |
| * Provides access to a concrete type and its optional generic type arguments. |
| * |
| * Java 5 and later support generic types. These types consist of a raw class |
| * with type arguments. This class models such a <code>Type</code> class but |
| * ensures that the type is <em>reified</em>. Reification means that the Type |
| * graph associated with a Java 5 <code>Type</code> instance is traversed |
| * until the type becomes a concrete class. In Java 1.4 a class has no |
| * arguments. This concrete class implements the Reified Type for Java 1.4. |
| * |
| * In Java 1.4, this class works with non-generic types. In that cases, a |
| * Reified Type provides access to the class and has zero type arguments, though |
| * a subclass that provide type arguments should be respected. Blueprint |
| * extender implementations can subclass this class and provide access to the |
| * generics type graph if used in a conversion. Such a subclass must |
| * <em>reify<em> the different Java 5 <code>Type</code> instances into the |
| * reified form. That is, a form where the raw Class is available with its optional type arguments as Reified Types. |
| * |
| * @Immutable |
| */ |
| public class ReifiedType { |
| final static ReifiedType ALL = new ReifiedType(Object.class); |
| |
| private final Class clazz; |
| |
| /** |
| * Create a Reified Type for a raw Java class without any generic arguments. |
| * Subclasses can provide the optional generic argument information. Without |
| * subclassing, this instance has no type arguments. |
| * |
| * @param clazz |
| * The raw class of the Reified Type. |
| */ |
| public ReifiedType(Class clazz) { |
| this.clazz = clazz; |
| } |
| |
| /** |
| * Access to the raw class. |
| * |
| * The raw class represents the concrete class that is associated with a |
| * type declaration. This class could have been deduced from the generics |
| * type graph of the declaration. For example, in the following example: |
| * |
| * <pre> |
| * Map<String, Object> map; |
| * </pre> |
| * |
| * The raw class is the Map class. |
| * |
| * @return the collapsed raw class that represents this type. |
| */ |
| public Class getRawClass() { |
| return clazz; |
| } |
| |
| /** |
| * Access to a type argument. |
| * |
| * The type argument refers to a argument in a generic type declaration |
| * given by index <code>i</code>. This method returns a Reified Type that |
| * has Object as class when no generic type information is available. Any |
| * object is assignable to Object and therefore no conversion is then |
| * necessary, this is compatible with older Javas than 5. For this reason, |
| * the implementation in this class always returns the |
| * <code>Object<code> class, regardless of the given index. |
| * |
| * This method should be overridden by a subclass that provides access to |
| * the generic information. |
| * |
| * For example, in the following example: |
| * |
| * <pre> |
| * Map<String, Object> map; |
| * </pre> |
| * |
| * The type argument 0 is <code>String</code>, and type argument 1 is |
| * <code>Object</code>. |
| * |
| * @param i |
| * The index of the type argument |
| * @return <code>ReifiedType(Object.class)<code>, subclasses must override this and return the generic argument at index <code>i</code> |
| */ |
| public ReifiedType getActualTypeArgument(int i) { |
| return ALL; |
| } |
| |
| /** |
| * Return the number of type arguments. |
| * |
| * This method should be overridden by a subclass to support Java 5 types. |
| * |
| * @return 0, subclasses must override this and return the number of generic |
| * arguments |
| */ |
| public int size() { |
| return 0; |
| } |
| } |