1 files changed, 104 insertions, 0 deletions
diff --git a/upstream/odl-aaa-moon/aaa/aaa-authn/src/main/java/org/opendaylight/aaa/HashCodeUtil.java b/upstream/odl-aaa-moon/aaa/aaa-authn/src/main/java/org/opendaylight/aaa/HashCodeUtil.java
new file mode 100644
index 00000000..c295b3ed
--- /dev/null
+++ b/upstream/odl-aaa-moon/aaa/aaa-authn/src/main/java/org/opendaylight/aaa/HashCodeUtil.java
@@ -0,0 +1,104 @@
+/*****************************************************************************
+ * Copyright (c) 2014 Hewlett-Packard Development Company, L.P. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ *****************************************************************************/
+
+package org.opendaylight.aaa;
+
+import java.lang.reflect.Array;
+
+/**
+ * Collected methods which allow easy implementation of <tt>hashCode</tt>.
+ *
+ * Example use case:
+ *
+ * <pre>
+ * public int hashCode() {
+ *     int result = HashCodeUtil.SEED;
+ *     // collect the contributions of various fields
+ *     result = HashCodeUtil.hash(result, fPrimitive);
+ *     result = HashCodeUtil.hash(result, fObject);
+ *     result = HashCodeUtil.hash(result, fArray);
+ *     return result;
+ * }
+ * </pre>
+ */
+public final class HashCodeUtil {
+
+    /**
+     * An initial value for a <tt>hashCode</tt>, to which is added contributions
+     * from fields. Using a non-zero value decreases collisions of
+     * <tt>hashCode</tt> values.
+     */
+    public static final int SEED = 23;
+
+    /** booleans. */
+    public static int hash(int aSeed, boolean aBoolean) {
+        return firstTerm(aSeed) + (aBoolean ? 1 : 0);
+    }
+
+    /*** chars. */
+    public static int hash(int aSeed, char aChar) {
+        return firstTerm(aSeed) + aChar;
+    }
+
+    /** ints. */
+    public static int hash(int aSeed, int aInt) {
+        return firstTerm(aSeed) + aInt;
+    }
+
+    /** longs. */
+    public static int hash(int aSeed, long aLong) {
+        return firstTerm(aSeed) + (int) (aLong ^ (aLong >>> 32));
+    }
+
+    /** floats. */
+    public static int hash(int aSeed, float aFloat) {
+        return hash(aSeed, Float.floatToIntBits(aFloat));
+    }
+
+    /** doubles. */
+    public static int hash(int aSeed, double aDouble) {
+        return hash(aSeed, Double.doubleToLongBits(aDouble));
+    }
+
+    /**
+     * <tt>aObject</tt> is a possibly-null object field, and possibly an array.
+     *
+     * If <tt>aObject</tt> is an array, then each element may be a primitive or
+     * a possibly-null object.
+     */
+    public static int hash(int aSeed, Object aObject) {
+        int result = aSeed;
+        if (aObject == null) {
+            result = hash(result, 0);
+        } else if (!isArray(aObject)) {
+            result = hash(result, aObject.hashCode());
+        } else {
+            int length = Array.getLength(aObject);
+            for (int idx = 0; idx < length; ++idx) {
+                Object item = Array.get(aObject, idx);
+                // if an item in the array references the array itself, prevent
+                // infinite looping
+                if (!(item == aObject)) {
+                    result = hash(result, item);
+                }
+            }
+        }
+        return result;
+    }
+
+    // PRIVATE
+    private static final int fODD_PRIME_NUMBER = 37;
+
+    private static int firstTerm(int aSeed) {
+        return fODD_PRIME_NUMBER * aSeed;
+    }
+
+    private static boolean isArray(Object aObject) {
+        return aObject.getClass().isArray();
+    }
+}
+\ No newline at end of file