New BiLong2ObjectMap implementation

agrona/src/main/java/org/agrona/collections/BiLong2NullableObjectMap.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2014-2023 Real Logic Limited.
+ *
+ * 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
+ *
+ * https://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.agrona.collections;
+
+/**
+ * Variation of {@link BiLong2ObjectMap} that allows {@code null} values.
+ *
+ * @param <V> type of values stored in the {@link java.util.Map}
+ */
+public class BiLong2NullableObjectMap<V> extends BiLong2ObjectMap<V>
+{
+    /**
+     * Constructs map with default settings.
+     */
+    public BiLong2NullableObjectMap()
+    {
+        super();
+    }
+
+    /**
+     * Constructs map with given initial capacity and load factory and enables caching of iterators.
+     *
+     * @param initialCapacity for the backing array.
+     * @param loadFactor      limit for resizing on puts.
+     */
+    public BiLong2NullableObjectMap(final int initialCapacity, final float loadFactor)
+    {
+        super(initialCapacity, loadFactor);
+    }
+
+    protected Object mapNullValue(final Object value)
+    {
+        return null == value ? NullReference.INSTANCE : value;
+    }
+
+    @SuppressWarnings("unchecked")
+    protected V unmapNullValue(final Object value)
+    {
+        return NullReference.INSTANCE == value ? null : (V)value;
+    }
+}