org.biojava.utils.ObjectUtil Maven / Gradle / Ivy
/*
* BioJava development code
*
* This code may be freely distributed and modified under the
* terms of the GNU Lesser General Public Licence. This should
* be distributed with the code. If you do not have a copy,
* see:
*
* http://www.gnu.org/copyleft/lesser.html
*
* Copyright for this code is held jointly by the individual
* authors. These should be listed in @author doc comments.
*
* For more information on the BioJava project and its aims,
* or to join the biojava-l mailing list, visit the home page
* at:
*
* http://www.biojava.org/
*
*/
package org.biojava.utils;
/**
* utility methods for implementing the equals() and hashCode() methods of Objects.
* All credit for this class goes to Mark Davis (Java Report 5(1), 46; Java Report 5(4), 60).
*
* All equals() methods in this class take the two fields to compare for equality as arguments and return whether they
* are equal. Consequently, the equals() method of class AClass should be implemented (taking advantage of the equals()
* methods in this class) as follows:
*
* public boolean equals(Object o) {
* if (o == this) return true;
* // if this class AClass is a direct sub-class of Object:
* if (o == null) return false;
* if (!o.getClass().equals(this.getClass())) return false;
* // else if this class AClass extends another class than Object:
* //if (!super.equals(o)) return false;
*
* AClass that = (AClass) o;
*
* // only compare fields of this class AClass (not of super-classes):
* //if (!ObjectUtil.equals(this.field, that.field)) return false;
*
* // this and that are identical if we made it 'til here
* return true;
* }
*
*
* All hashCode() methods in this class take the current hashCode value as the first argument and the field to take into
* account as the second argument and return the newly calculated hashCode value (which now includes the influence of
* the given field). Consequently, the hashCode() method of class AClass should be implemented (taking advantage of the
* hashCode() methods in this class) as follows:
*
* public int hashCode() {
* // if this class AClass is a direct sub-class of Object:
* int hc = 0;
* // else if this class AClass extends another class than Object:
* //int hc = super.hashCode();
*
* // only take into account fields of this class AClass (not of super-class):
* //hc = ObjectUtil.hashCode(hc, field);
*
* return hc;
* }
*
*
* @author Gerald Loeffler
*/
public final class ObjectUtil {
/**
* the current hashCode is always first multiplied with this prime before the hashCode value for a particular field is
* added.
*/
public static final int PRIME = 1000003;
public static boolean equals(boolean b1, boolean b2) {
return b1 == b2;
}
public static boolean equals(int i1, int i2) {
return i1 == i2;
}
public static boolean equals(long l1, long l2) {
return l1 == l2;
}
public static boolean equals(float f1, float f2) {
return ((Float.isNaN(f1) && Float.isNaN(f2)) || (f1 == f2));
}
public static boolean equals(double d1, double d2) {
return ((Double.isNaN(d1) && Double.isNaN(d2)) || (d1 == d2));
}
public static boolean equals(boolean[] a1, boolean[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(int[] a1, int[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(long[] a1, long[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(float[] a1, float[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(double[] a1, double[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(Object[] a1, Object[] a2) {
if (a1 == null && a2 == null) return true;
if (!(a1 != null && a2 != null)) return false;
final int l = a1.length;
if (l != a2.length) return false;
for (int i = 0; i < l; i++) {
if (!equals(a1[i], a2[i])) return false;
}
return true;
}
public static boolean equals(Object o1, Object o2) {
return ((o1 == null && o2 == null) || (o1 != null && o1.equals(o2)) || (o2 != null && o2.equals(o1)));
}
public static int hashCode(int currentHashCodeValue, boolean b) {
return PRIME*currentHashCodeValue + (b ? 1 : 0);
}
public static int hashCode(int currentHashCodeValue, int i) {
return PRIME*currentHashCodeValue + i;
}
public static int hashCode(int currentHashCodeValue, long l) {
return PRIME*(PRIME*currentHashCodeValue + ((int) (l>>>32))) + ((int) (l&0xFFFFFFFF));
}
public static int hashCode(int currentHashCodeValue, float f) {
return hashCode(currentHashCodeValue, f == 0.0F ? 0 : Float.floatToIntBits(f));
}
public static int hashCode(int currentHashCodeValue, double d) {
return hashCode(currentHashCodeValue, d == 0.0 ? 0L : Double.doubleToLongBits(d));
}
public static int hashCode(int currentHashCodeValue, boolean[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, int[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, long[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, float[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, double[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, Object[] a) {
if (a == null) return PRIME*currentHashCodeValue;
final int l = a.length;
for (int i = 0; i < l; i++) {
currentHashCodeValue = hashCode(currentHashCodeValue, a[i]);
}
return currentHashCodeValue;
}
public static int hashCode(int currentHashCodeValue, Object o) {
return PRIME*currentHashCodeValue + (o == null ? 0 : o.hashCode());
}
}
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