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+/*
+ * 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 android.util;
+
+/**
+ * Container to ease passing around a tuple 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. If either are null then equals() and hashCode() will throw
+ * a NullPointerException.
+ * @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 equals() methods.
+ * @param o the Pair to which this one is to be checked for equality
+ * @return true if the underlying objects of the Pair are both considered equals()
+ */
+ public boolean equals(Object o) {
+ if (o == this) return true;
+ if (!(o instanceof Pair)) return false;
+ final Pair<F, S> other;
+ try {
+ other = (Pair<F, S>) o;
+ } catch (ClassCastException e) {
+ return false;
+ }
+ return first.equals(other.first) && second.equals(other.second);
+ }
+
+ /**
+ * Compute a hash code using the hash codes of the underlying objects
+ * @return a hashcode of the Pair
+ */
+ public int hashCode() {
+ int result = 17;
+ result = 31 * result + first.hashCode();
+ result = 31 * result + second.hashCode();
+ return result;
+ }
+
+ /**
+ * 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);
+ }
+}