Initial checkin

qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/CountingHash.java

@@ -0,0 +1,126 @@
+/*
+ * QQQ - Low-code Application Framework for Engineers.
+ * Copyright (C) 2021-2024.  Kingsrook, LLC
+ * 651 N Broad St Ste 205 # 6917 | Middletown DE 19709 | United States
+ * contact@kingsrook.com
+ * https://github.com/Kingsrook/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.kingsrook.qqq.backend.core.utils;
+
+
+import java.io.Serializable;
+import java.util.AbstractMap;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import com.kingsrook.qqq.backend.core.utils.collections.MutableMap;
+
+
+/*******************************************************************************
+ ** Hash that provides "counting" capability -- keys map to Integers that
+ ** are automatically/easily summed to
+ **
+ *******************************************************************************/
+public class CountingHash<K extends Serializable> extends AbstractMap<K, Integer> implements Serializable
+{
+   private Map<K, Integer> map = null;
+
+
+
+   /*******************************************************************************
+    ** Default constructor
+    **
+    *******************************************************************************/
+   public CountingHash()
+   {
+      this.map = new HashMap<>();
+   }
+
+
+
+   /*******************************************************************************
+    ** Constructor where you can supply a source map (e.g., if you want a specific
+    ** Map type (like LinkedHashMap), or with pre-values.
+    **
+    ** Note - the input map will be wrapped in a MutableMap - so - it'll be mutable.
+    **
+    *******************************************************************************/
+   public CountingHash(Map<K, Integer> sourceMap)
+   {
+      this.map = new MutableMap<>(sourceMap);
+   }
+
+
+
+   /*******************************************************************************
+    ** Increment the value for the specified key by 1.
+    **
+    *******************************************************************************/
+   public Integer add(K key)
+   {
+      Integer value = getOrCreateListForKey(key);
+      Integer sum   = value + 1;
+      map.put(key, sum);
+      return (sum);
+   }
+
+
+
+   /*******************************************************************************
+    ** Increment the value for the specified key by the supplied addend
+    **
+    *******************************************************************************/
+   public Integer add(K key, Integer addend)
+   {
+      Integer value = getOrCreateListForKey(key);
+      Integer sum   = value + addend;
+      map.put(key, sum);
+      return (sum);
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   private Integer getOrCreateListForKey(K key)
+   {
+      Integer value;
+
+      if(!this.map.containsKey(key))
+      {
+         this.map.put(key, 0);
+         value = 0;
+      }
+      else
+      {
+         value = this.map.get(key);
+      }
+      return value;
+   }
+
+
+
+   /***************************************************************************
+    *
+    ***************************************************************************/
+   public Set<Entry<K, Integer>> entrySet()
+   {
+      return this.map.entrySet();
+   }
+
+}