HashCode.java
- /**
- *
- * Copyright 2019 Florian Schmaus.
- *
- * 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 org.jivesoftware.smack.util;
- public class HashCode {
- private static final int MULTIPLIER_VALUE = 37;
- public static class Cache {
- private boolean calculated;
- private int hashcode;
- public int getHashCode(Calculator hashCodeCalculator) {
- if (calculated) {
- return hashcode;
- }
- HashCode.Builder hashCodeBuilder = new HashCode.Builder();
- hashCodeCalculator.calculateHash(hashCodeBuilder);
- calculated = true;
- hashcode = hashCodeBuilder.hashcode;
- return hashcode;
- }
- }
- @FunctionalInterface
- public interface Calculator {
- void calculateHash(HashCode.Builder hashCodeBuilder);
- }
- public static Builder builder() {
- return new Builder();
- }
- public static class Builder {
- private int hashcode = 17;
- private void applyHash() {
- applyHash(0);
- }
- private void applyHash(int hash) {
- hashcode = MULTIPLIER_VALUE * hashcode + hash;
- }
- public Builder append(Object object) {
- if (object == null) {
- applyHash();
- return this;
- }
- if (object.getClass().isArray()) {
- if (object instanceof int[]) {
- append((int[]) object);
- } else if (object instanceof long[]) {
- append((long[]) object);
- } else if (object instanceof boolean[]) {
- append((boolean[]) object);
- } else if (object instanceof double[]) {
- append((double[]) object);
- } else if (object instanceof float[]) {
- append((float[]) object);
- } else if (object instanceof short[]) {
- append((short[]) object);
- } else if (object instanceof char[]) {
- append((char[]) object);
- } else if (object instanceof byte[]) {
- append((byte[]) object);
- } else {
- append((Object[]) object);
- }
- }
- applyHash(object.hashCode());
- return this;
- }
- public Builder append(boolean value) {
- applyHash(value ? 0 : 1);
- return this;
- }
- public Builder append(boolean[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (boolean bool : array) {
- append(bool);
- }
- return this;
- }
- public Builder append(byte value) {
- applyHash(value);
- return this;
- }
- public Builder append(byte[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (byte b : array) {
- append(b);
- }
- return this;
- }
- public Builder append(char value) {
- applyHash(value);
- return this;
- }
- public Builder append(char[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (char c : array) {
- append(c);
- }
- return this;
- }
- public Builder append(double value) {
- return append(Double.doubleToLongBits(value));
- }
- public Builder append(double[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (double d : array) {
- append(d);
- }
- return this;
- }
- public Builder append(float value) {
- return append(Float.floatToIntBits(value));
- }
- public Builder append(float[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (float f : array) {
- append(f);
- }
- return this;
- }
- public Builder append(long value) {
- applyHash((int) (value ^ (value >>> 32)));
- return this;
- }
- public Builder append(long[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (long l : array) {
- append(l);
- }
- return this;
- }
- public Builder append(Object[] array) {
- if (array == null) {
- applyHash();
- return this;
- }
- for (Object element : array) {
- append(element);
- }
- return this;
- }
- public int build() {
- return hashcode;
- }
- }
- }