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 }
--- EOF ---