1 /* 2 * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.codegen; 27 28 import java.util.HashMap; 29 30 /** 31 * A name space hierarchy, where each level holds a name directory with 32 * names that may be unique for each level. 33 */ 34 35 public class Namespace { 36 /** Parent namespace. */ 37 private final Namespace parent; 38 39 /** Name directory - version count for each name */ 40 private final HashMap<String, Integer> directory; 41 42 /** 43 * Constructor 44 */ 45 public Namespace() { 46 this(null); 47 } 48 49 /** 50 * Constructor 51 * 52 * @param parent parent name space 53 */ 54 public Namespace(final Namespace parent) { 55 this.parent = parent; 56 this.directory = new HashMap<>(); 57 } 58 59 /** 60 * Return the parent Namespace of this space. 61 * 62 * @return parent name space 63 */ 64 public Namespace getParent() { 65 return parent; 66 } 67 68 /** 69 * Create a uniqueName name in the namespace in the form base$n where n varies 70 * . 71 * @param base Base of name. Base will be returned if uniqueName. 72 * 73 * @return Generated uniqueName name. 74 */ 75 public String uniqueName(final String base) { 76 for (Namespace namespace = this; namespace != null; namespace = namespace.getParent()) { 77 final HashMap<String, Integer> namespaceDirectory = namespace.directory; 78 final Integer counter = namespaceDirectory.get(base); 79 80 if (counter != null) { 81 final int count = counter + 1; 82 namespaceDirectory.put(base, count); 83 return base + '-' + count; 84 } 85 } 86 87 directory.put(base, 0); 88 89 return base; 90 } 91 92 @Override 93 public String toString() { 94 return directory.toString(); 95 } 96 }