Ref: cleanup, organise packages

src/main/java/com/sheepit/client/utils/Pair.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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 com.sheepit.client.utils;
+
+import java.util.Objects;
+
+/**
+ * Container to ease passing around a pair of two objects. This object provides a sensible
+ * implementation of equals(), returning true if equals() is true on each of the contained
+ * objects.
+ */
+public class Pair<F, S> {
+	public final F first;
+	public final S second;
+	
+	/**
+	 * Constructor for a Pair.
+	 *
+	 * @param first  the first object in the Pair
+	 * @param second the second object in the pair
+	 */
+	public Pair(F first, S second) {
+		this.first = first;
+		this.second = second;
+	}
+	
+	/**
+	 * Checks the two objects for equality by delegating to their respective
+	 * {@link Object#equals(Object)} methods.
+	 *
+	 * @param o the {@link Pair} to which this one is to be checked for equality
+	 * @return true if the underlying objects of the Pair are both considered
+	 * equal
+	 */
+	@Override public boolean equals(Object o) {
+		if (!(o instanceof Pair)) {
+			return false;
+		}
+		Pair<?, ?> p = (Pair<?, ?>) o;
+		return Objects.equals(p.first, first) && Objects.equals(p.second, second);
+	}
+	
+	/**
+	 * Compute a hash code using the hash codes of the underlying objects
+	 *
+	 * @return a hashcode of the Pair
+	 */
+	@Override public int hashCode() {
+		return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
+	}
+	
+	/**
+	 * Convenience method for creating an appropriately typed pair.
+	 *
+	 * @param a the first object in the Pair
+	 * @param b the second object in the pair
+	 * @return a Pair that is templatized with the types of a and b
+	 */
+	public static <A, B> Pair<A, B> create(A a, B b) {
+		return new Pair<A, B>(a, b);
+	}
+}