net.gdface.utils.Pair Maven / Gradle / Ivy
package net.gdface.utils;
import java.io.Serializable;
/**
* A convenience class to represent name-value pairs.
* copy from javafx.util.Pair,and refer to org.apache.commons.lang3.tuple.Pair
*/
public class Pair implements Serializable{
private static final long serialVersionUID = -4496481498313465718L;
/** Left object */
public final L left;
/** Right object */
public final R right;
//-----------------------------------------------------------------------
/**
* Gets the left element from this pair.
*
* When treated as a left-value pair, this is the left.
*
* @return the left element, may be null
*/
public L getLeft(){ return left; }
/**
* Gets the right element from this pair.
*
* When treated as a left-value pair, this is the value.
*
* @return the right element, may be null
*/
public R getRight(){ return right; }
/**
* Gets the left for this pair.
* @return left for this pair
*/
public L getKey() { return getLeft(); }
/**
* Gets the value for this pair.
* @return value for this pair
*/
public R getValue() { return getRight(); }
/**
* Creates a new pair
* @param key The left for this pair
* @param value The value to use for this pair
*/
public Pair(L key, R value) {
this.left = key;
this.right = value;
}
/**
* String representation of this
* Pair.
*
* The default name/value delimiter '=' is always used.
*
* @return String representation of this Pair
*/
@Override
public String toString() {
return left + "=" + right;
}
/**
* Generate a hash code for this Pair.
*
* The hash code is calculated using both the name and
* the value of the Pair.
*
* @return hash code for this Pair
*/
@Override
public int hashCode() {
// name's hashCode is multiplied by an arbitrary prime number (13)
// in order to make sure there is a difference in the hashCode between
// these two parameters:
// name: a value: aa
// name: aa value: a
return left.hashCode() * 13 + (right == null ? 0 : right.hashCode());
}
/**
* Test this Pair for equality with another
* Object.
*
* If the Object to be tested is not a
* Pair or is null, then this method
* returns false.
*
* Two Pairs are considered equal if and only if
* both the names and values are equal.
*
* @param o the Object to test for
* equality with this Pair
* @return true if the given Object is
* equal to this Pair else false
*/
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o instanceof Pair) {
@SuppressWarnings("rawtypes")
Pair pair = (Pair) o;
if (left != null ? !left.equals(pair.left) : pair.left != null) return false;
if (right != null ? !right.equals(pair.right) : pair.right != null) return false;
return true;
}
return false;
}
/**
* Obtains an pair of from two objects inferring the generic types.
*
* This factory allows the pair to be created using inference to
* obtain the generic types.
*
* @param the left element type
* @param the right element type
* @param left the left element, may be null
* @param right the right element, may be null
* @return a pair formed from the two parameters, not null
*/
public static Pair of(L left, R right) {
return new Pair(left, right);
}
}