1 /* 2 * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.reflect.generics.repository; 27 28 import java.lang.reflect.TypeVariable; 29 import sun.reflect.generics.factory.GenericsFactory; 30 import sun.reflect.generics.tree.FormalTypeParameter; 31 import sun.reflect.generics.tree.Signature; 32 import sun.reflect.generics.visitor.Reifier; 33 34 35 36 /** 37 * This class represents the generic type information for a generic 38 * declaration. 39 * The code is not dependent on a particular reflective implementation. 40 * It is designed to be used unchanged by at least core reflection and JDI. 41 */ 42 public abstract class GenericDeclRepository<S extends Signature> 43 extends AbstractRepository<S> { 44 45 /** The formal type parameters. Lazily initialized. */ 46 private volatile TypeVariable<?>[] typeParameters; 47 48 protected GenericDeclRepository(String rawSig, GenericsFactory f) { 49 super(rawSig, f); 50 } 51 52 /* 53 * When queried for a particular piece of type information, the 54 * general pattern is to consult the corresponding cached value. 55 * If the corresponding field is non-null, it is returned. 56 * If not, it is created lazily. This is done by selecting the appropriate 57 * part of the tree and transforming it into a reflective object 58 * using a visitor, which is created by feeding it the factory 59 * with which the repository was created. 60 */ 61 62 /** 63 * Returns the formal type parameters of this generic declaration. 64 * @return the formal type parameters of this generic declaration 65 */ 66 public TypeVariable<?>[] getTypeParameters() { 67 TypeVariable<?>[] value = typeParameters; 68 if (value == null) { 69 value = computeTypeParameters(); 70 typeParameters = value; 71 } 72 return value.clone(); 73 } 74 75 private TypeVariable<?>[] computeTypeParameters() { 76 // first, extract type parameter subtree(s) from AST 77 FormalTypeParameter[] ftps = getTree().getFormalTypeParameters(); 78 // create array to store reified subtree(s) 79 int length = ftps.length; 80 TypeVariable<?>[] typeParameters = new TypeVariable<?>[length]; 81 // reify all subtrees 82 for (int i = 0; i < length; i++) { 83 Reifier r = getReifier(); // obtain visitor 84 ftps[i].accept(r); // reify subtree 85 // extract result from visitor and store it 86 typeParameters[i] = (TypeVariable<?>) r.getResult(); 87 } 88 return typeParameters; 89 } 90 }