Package org.apache.commons.math4.util

Class Pair<K,​V>

java.lang.Object
org.apache.commons.math4.util.Pair<K,​V>
Type Parameters:
K - Key type.
V - Value type.
public class Pair<K,​V>
extends java.lang.Object
Generic pair.
Although the instances of this class are immutable, it is impossible to ensure that the references passed to the constructor will not be modified by the caller.
Since:
3.0

  • Constructor Summary

    Constructors 
    Constructor Description
    Pair​(K k, V v)
    Create an entry representing a mapping from the specified key to the specified value.
    Pair​(Pair<? extends K,​? extends V> entry)
    Create an entry representing the same mapping as the specified entry.

  • Method Summary

    Modifier and Type Method Description
    static <K,​ V> Pair<K,​V> create​(K k, V v)
    Convenience factory method that calls the constructor.
    boolean equals​(java.lang.Object o)
    Compare the specified object with this entry for equality.
    K getFirst()
    Get the first element of the pair.
    K getKey()
    Get the key.
    V getSecond()
    Get the second element of the pair.
    V getValue()
    Get the value.
    int hashCode()
    Compute a hash code.
    java.lang.String toString()

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • Pair

      public Pair​(K k, V v)
      Create an entry representing a mapping from the specified key to the specified value.
      Parameters:
      k - Key (first element of the pair).
      v - Value (second element of the pair).

    • Pair

      public Pair​(Pair<? extends K,​? extends V> entry)
      Create an entry representing the same mapping as the specified entry.
      Parameters:
      entry - Entry to copy.

  • Method Details

    • getKey

      public K getKey()
      Get the key.
      Returns:
      the key (first element of the pair).

    • getValue

      public V getValue()
      Get the value.
      Returns:
      the value (second element of the pair).

    • getFirst

      public K getFirst()
      Get the first element of the pair.
      Returns:
      the first element of the pair.
      Since:
      3.1

    • getSecond

      public V getSecond()
      Get the second element of the pair.
      Returns:
      the second element of the pair.
      Since:
      3.1

    • equals

      public boolean equals​(java.lang.Object o)
      Compare the specified object with this entry for equality.
      Overrides:
      equals in class java.lang.Object
      Parameters:
      o - Object.
      Returns:
      true if the given object is also a map entry and the two entries represent the same mapping.

    • hashCode

      public int hashCode()
      Compute a hash code.
      Overrides:
      hashCode in class java.lang.Object
      Returns:
      the hash code value.

    • toString

      public java.lang.String toString()
      Overrides:
      toString in class java.lang.Object

    • create

      public static <K,​ V> Pair<K,​V> create​(K k, V v)
      Convenience factory method that calls the constructor.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      k - First element of the pair.
      v - Second element of the pair.
      Returns:
      a new Pair containing k and v.
      Since:
      3.3