JAL-3878 Add action and task for annotation services

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

diff --git a/src/jalview/util/Pair.java b/src/jalview/util/Pair.java
new file mode 100644 (file)
index 0000000..63cf7e9
--- /dev/null
+++ b/src/jalview/util/Pair.java
@@ -0,0 +1,88 @@
+package jalview.util;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * A generic immutable pair of values.
+ * 
+ * @author mmwarowny
+ *
+ * @param <T>
+ *          first value type
+ * @param <U>
+ *          second value type
+ */
+public class Pair<T, U> implements Iterable<Object>
+{
+  final T val0;
+
+  final U val1;
+
+  public Pair(T val0, U val1)
+  {
+    this.val0 = val0;
+    this.val1 = val1;
+  }
+  
+  /**
+   * Return value at the specified index cast to type R
+   * @param <R> return type
+   * @param index item index
+   * @return value at given index
+   * @throws ClassCastException value cannot be cast to R
+   * @throws IndexOutOfBoundsException index outside tuple size
+   */
+  @SuppressWarnings("unchecked")
+  public <R> R get(int index) throws ClassCastException, IndexOutOfBoundsException
+  {
+    if (index == 0)
+      return (R) val0;
+    if (index == 1)
+      return (R) val1;
+    throw new IndexOutOfBoundsException(index);
+  }
+
+  /**
+   * @return 0th value of the pair
+   */
+  public T get0()
+  {
+    return val0;
+  }
+
+  /**
+   * @return 1st value of the pair
+   */
+  public U get1()
+  {
+    return val1;
+  }
+  
+  /**
+   * @return tuple size
+   */
+  public int size()
+  {
+    return 2;
+  }
+
+  @Override
+  public boolean equals(Object obj)
+  {
+    if (obj instanceof Pair)
+    {
+      Pair<?, ?> other = (Pair<?, ?>) obj;
+      return Objects.equals(val0, other.val0) &&
+          Objects.equals(val1, other.val1);
+    }
+    return false;
+  }
+
+  @Override
+  public Iterator<Object> iterator()
+  {
+    return List.of(val0, val1).iterator();
+  }
+}