Here you can find the source of hash(int hash, boolean item)
public static int hash(int hash, boolean item)
//package com.java2s; //License from project: GNU General Public License public class Main { /** Odd prime number. */ private static int prime = 31; /** Seed. *///from w w w. j a va2 s . co m private static int seed = 17; /** Add a boolean value to a given hash. */ public static int hash(int hash, boolean item) { return hash * prime + (item ? 1 : 0); } /** Add a char value to a given hash. */ public static int hash(int hash, char item) { return hash * prime + item; } /** Add an int value to a given hash. */ public static int hash(int hash, int item) { return hash * prime + item; } /** Add a long value to a given hash. */ public static int hash(int hash, long item) { return hash * prime + (int) (item ^ (item >>> 32)); } /** Add a float value to a given hash. */ public static int hash(int hash, float item) { return hash * prime + Float.floatToIntBits(item); } /** Add a double value to a given hash. */ public static int hash(int hash, double item) { long l = Double.doubleToLongBits(item); return seed * prime + (int) (l ^ (l >>> 32)); } /** Add an object to a given hash. */ public static int hash(int hash, Object item) { if (item == null) { return hash * prime; } return hash * prime + item.hashCode(); } /** Hash a boolean value. */ public static int hash(boolean item) { return (item ? 1 : 0); } /** Hash a char value. */ public static int hash(char item) { return item; } /** Hash an int value. */ public static int hash(int item) { return item; } /** Hash a long value. */ public static int hash(long item) { return (int) (item ^ (item >>> 32)); } /** Hash a float value. */ public static int hash(float item) { return Float.floatToIntBits(item); } /** Hash a double value. */ public static int hash(double item) { long l = Double.doubleToLongBits(item); return (int) (l ^ (l >>> 32)); } /** Hash an object. */ public static int hash(Object item) { if (item == null) { return 0; } return item.hashCode(); } /** Hash multiple objects. */ public static int hash(Object... items) { int result = seed; for (Object item : items) { result = result * prime + (item == null ? 0 : item.hashCode()); } return result; } }