Merge branch 'develop' into features/JAL-518_justify_seqs_in_region

[jalview.git] / src / jalview / util / MapUtils.java

diff --git a/src/jalview/util/MapUtils.java b/src/jalview/util/MapUtils.java
new file mode 100644 (file)
index 0000000..3cc1244
--- /dev/null
+++ b/src/jalview/util/MapUtils.java
@@ -0,0 +1,77 @@
+/*
+ * Jalview - A Sequence Alignment Editor and Viewer ($$Version-Rel$$)
+ * Copyright (C) $$Year-Rel$$ The Jalview Authors
+ * 
+ * This file is part of Jalview.
+ * 
+ * Jalview is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License 
+ * as published by the Free Software Foundation, either version 3
+ * of the License, or (at your option) any later version.
+ *  
+ * Jalview 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
+ * The Jalview Authors are detailed in the 'AUTHORS' file.
+ */
+package jalview.util;
+
+import java.util.Map;
+
+public class MapUtils
+{
+  /**
+   * Return the value of the first key that exists in the map and has a non-null
+   * value
+   */
+  public static <K, V> V getFirst(Map<K, V> map, K... keys)
+  {
+    return getFirst(false, map, keys);
+  }
+
+  /**
+   * Return the value of the first key that exists in the map - optionally
+   * limiting to only returning non-null values for first extant key encountered
+   */
+  public static <K, V> V getFirst(boolean nonNull, Map<K, V> map, K... keys)
+  {
+    for (K key : keys)
+    {
+      if (map.containsKey(key))
+      {
+        if (!(nonNull && (map.get(key) == null)))
+        {
+          return map.get(key);
+        }
+        else if (!nonNull)
+        {
+          return map.get(key);
+        }
+      }
+    }
+    return null;
+  }
+
+  /**
+   * peeks in to the map and returns true if one of a bunch of keys is contained
+   * in it
+   * 
+   * @param <K>
+   * @param map
+   * @param keys
+   * @return
+   */
+  public static <K> boolean containsAKey(Map<K, ?> map, K... keys)
+  {
+    for (K key : keys)
+    {
+      if (map.containsKey(key))
+        return true;
+    }
+    return false;
+  }
+}