From cd8caf797faf6b08e18f85afa5a4b6cce8bc7692 Mon Sep 17 00:00:00 2001 From: Sven Gothel Date: Fri, 1 Apr 2011 07:06:55 +0200 Subject: Folded turtle2d into jogl folders --- .../classes/org/apache/harmony/misc/HashCode.java | 203 +++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 src/jogl/classes/org/apache/harmony/misc/HashCode.java (limited to 'src/jogl/classes/org/apache') diff --git a/src/jogl/classes/org/apache/harmony/misc/HashCode.java b/src/jogl/classes/org/apache/harmony/misc/HashCode.java new file mode 100644 index 000000000..e8ce8f620 --- /dev/null +++ b/src/jogl/classes/org/apache/harmony/misc/HashCode.java @@ -0,0 +1,203 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.harmony.misc; + +/** + * This class is a convenience method to sequentially calculate hash code of the + * object based on the field values. The result depends on the order of elements + * appended. The exact formula is the same as for + * java.util.List.hashCode. + * + * If you need order independent hash code just summate, multiply or XOR all + * elements. + * + *

+ * Suppose we have class: + * + * 


+ * class Thing {
+ *     long id;
+ *     String name;
+ *     float weight;
+ * }
+ *
+ * + * The hash code calculation can be expressed in 2 forms. + * + *

+ * For maximum performance: + * + * 


+ * public int hashCode() {
+ *     int hashCode = HashCode.EMPTY_HASH_CODE;
+ *     hashCode = HashCode.combine(hashCode, id);
+ *     hashCode = HashCode.combine(hashCode, name);
+ *     hashCode = HashCode.combine(hashCode, weight);
+ *     return hashCode;
+ * }
+ *
+ * + *

+ * For convenience: 

+ * public int hashCode() {
+ *     return new HashCode().append(id).append(name).append(weight).hashCode();
+ * }
+ *
+ * + * @see java.util.List#hashCode() + */ +public final class HashCode { + /** + * The hashCode value before any data is appended, equals to 1. + * @see java.util.List#hashCode() + */ + public static final int EMPTY_HASH_CODE = 1; + + private int hashCode = EMPTY_HASH_CODE; + + /** + * Returns accumulated hashCode + */ + public final int hashCode() { + return hashCode; + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, boolean value) { + int v = value ? 1231 : 1237; + return combine(hashCode, v); + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, long value) { + int v = (int) (value ^ (value >>> 32)); + return combine(hashCode, v); + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, float value) { + int v = Float.floatToIntBits(value); + return combine(hashCode, v); + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, double value) { + long v = Double.doubleToLongBits(value); + return combine(hashCode, v); + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, Object value) { + return combine(hashCode, value.hashCode()); + } + + /** + * Combines hashCode of previous elements sequence and value's hashCode. + * @param hashCode previous hashCode value + * @param value new element + * @return combined hashCode + */ + public static int combine(int hashCode, int value) { + return 31 * hashCode + value; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(int value) { + hashCode = combine(hashCode, value); + return this; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(long value) { + hashCode = combine(hashCode, value); + return this; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(float value) { + hashCode = combine(hashCode, value); + return this; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(double value) { + hashCode = combine(hashCode, value); + return this; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(boolean value) { + hashCode = combine(hashCode, value); + return this; + } + + /** + * Appends value's hashCode to the current hashCode. + * @param value new element + * @return this + */ + public final HashCode append(Object value) { + hashCode = combine(hashCode, value); + return this; + } +} -- cgit v1.2.3