modules/cldc-compact/src/main/java/cc/squirreljme/runtime/cldc/util/MapKeySetView.java

   1 // -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
   2 // ---------------------------------------------------------------------------
   3 // SquirrelJME
   4 //     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
   5 // ---------------------------------------------------------------------------
   6 // SquirrelJME is under the GNU General Public License v3+, or later.
   7 // See license.mkd for licensing and copyright information.
   8 // ---------------------------------------------------------------------------
   9
  10 package cc.squirreljme.runtime.cldc.util;
  11
  12 import java.util.AbstractSet;
  13 import java.util.Iterator;
  14 import java.util.Map;
  15
  16 /**
  17  * This is the key set for an abstract map.
  18  *
  19  * @param <K> The key type.
  20  * @param <V> The value stored.
  21  * @since 2018/10/10
  22  */
  23 public final class MapKeySetView<K, V>
  24         extends AbstractSet<K>
  25 {
  26         /** The backing map. */
  27         protected final Map<K, V> map;
  28
  29         /** Is adding allowed? */
  30         protected final boolean allowAdd;
  31
  32         /**
  33          * Initializes the set.
  34          *
  35          * @param __map The backing map
  36          * @param __allowAdd Is adding allowed in the map?
  37          * @throws NullPointerException On null arguments.
  38          * @since 2018/11/01
  39          */
  40         public MapKeySetView(Map<K, V> __map, boolean __allowAdd)
  41                 throws NullPointerException
  42         {
  43                 if (__map == null)
  44                         throw new NullPointerException("NARG");
  45
  46                 this.map = __map;
  47                 this.allowAdd = __allowAdd;
  48         }
  49
  50         /**
  51          * {@inheritDoc}
  52          * @since 2021/11/28
  53          */
  54         @Override
  55         public boolean add(K __k)
  56         {
  57                 if (!this.allowAdd)
  58                         throw new UnsupportedOperationException("RORO");
  59
  60                 // Store a null value here
  61                 Map<K, V> map = this.map;
  62                 boolean contained = map.containsKey(__k);
  63                 map.put(__k, null);
  64
  65                 // Only if it is actually contained here
  66                 return !contained;
  67         }
  68
  69         /**
  70          * {@inheritDoc}
  71          * @since 2018/11/01
  72          */
  73         @SuppressWarnings("SuspiciousMethodCalls")
  74         @Override
  75         public final boolean contains(Object __o)
  76         {
  77                 return this.map.containsKey(__o);
  78         }
  79
  80         /**
  81          * {@inheritDoc}
  82          * @since 2018/10/10
  83          */
  84         @Override
  85         public final Iterator<K> iterator()
  86         {
  87                 return new __MapKeySetIterator__<K, V>(this.map.entrySet().iterator());
  88         }
  89
  90         /**
  91          * {@inheritDoc}
  92          * @since 2021/11/28
  93          */
  94         @SuppressWarnings("SuspiciousMethodCalls")
  95         @Override
  96         public boolean remove(Object __o)
  97         {
  98                 // Remove the item from the map, but check to ensure it has it before
  99                 // that is actually done
 100                 Map<K, V> map = this.map;
 101                 boolean hasKey = map.containsKey(__o);
 102                 map.remove(__o);
 103
 104                 return hasKey;
 105         }
 106
 107         /**
 108          * {@inheritDoc}
 109          * @since 2018/10/10
 110          */
 111         @Override
 112         public final int size()
 113         {
 114                 return this.map.size();
 115         }
 116 }
 117