# Class Triple<L,M,R>

java.lang.Object
org.apache.commons.lang3.tuple.Triple<L,M,R>

Type Parameters:
  `L` - the left element type.
  `M` - the middle element type.
  `R` - the right element type.

All Implemented Interfaces:
  `Serializable, Comparable<Triple<L,M,R>>`

Direct Known Subclasses:
  `ImmutableTriple, MutableTriple`

public abstract class Triple<L,M,R> extends Object implements Comparable<Triple<L,M,R>>, Serializable
A triple consisting of three elements.

This class is an abstract implementation defining the basic API. It refers to the elements as 'left', 'middle' and 'right'.

Subclass implementations may be mutable or immutable. However, there is no restriction on the type of the stored objects that may be stored. If mutable objects are stored in the triple, then the triple itself effectively becomes mutable.

Since:
  3.2
See Also:
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final Triple<?,?,?>[]`
  `EMPTY_ARRAY`
  An empty array.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Triple()`
  Constructs a new instance.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `compareTo(Triple<L,M,R> other)`
  Compares the triple based on the left element, followed by the middle element, finally the right element.
  `static <L,M,R> Triple<L,M,R>[]`
  `emptyArray()`
  Returns the empty array singleton that can be assigned without compiler warning.
  `boolean`
  `equals(Object obj)`
  Compares this triple to another based on the three elements.
  `abstract L`
  `getLeft()`
  Gets the left element from this triple.
  `abstract M`
  `getMiddle()`
  Gets the middle element from this triple.
  `abstract R`
  `getRight()`
  Gets the right element from this triple.
  `int`
  `hashCode()`
  Returns a suitable hash code.
  `static <L,M,R> Triple<L,M,R>`
  `of(L left, M middle, R right)`
  Obtains an immutable triple of three objects inferring the generic types.
  `static <L,M,R> Triple<L,M,R>`
  `ofNonNull(L left, M middle, R right)`
  Obtains an immutable triple of three non-null objects inferring the generic types.
  `String`
  `toString()`
  Returns a String representation of this triple using the format `(left,middle,right)`.
  `String`
  `toString(String format)`
  Formats the receiver using the given format.

  ### Methods inherited from class Object

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

- ## Field Details

  - ### EMPTY_ARRAY

    public static final Triple<?,?,?>[] EMPTY_ARRAY
    An empty array.

    Consider using `emptyArray()` to avoid generics warnings.

    Since:
      3.10

- ## Constructor Details

  - ### Triple

    public Triple()
    Constructs a new instance.

- ## Method Details

  - ### emptyArray

    public static <L,M,R> Triple<L,M,R>[] emptyArray()
    Returns the empty array singleton that can be assigned without compiler warning.
    Type Parameters:
      `L` - the left element type.
      `M` - the middle element type.
      `R` - the right element type.
    Returns:
      the empty array singleton that can be assigned without compiler warning.
    Since:
      3.10

  - ### of

    public static <L,M,R> Triple<L,M,R> of(L left, M middle, R right)
    Obtains an immutable triple of three objects inferring the generic types.
    Type Parameters:
      `L` - the left element type.
      `M` - the middle element type.
      `R` - the right element type.
    Parameters:
      `left` - the left element, may be null.
      `middle` - the middle element, may be null.
      `right` - the right element, may be null.
    Returns:
      an immutable triple formed from the three parameters, not null.

  - ### ofNonNull

    public static <L,M,R> Triple<L,M,R> ofNonNull(L left, M middle, R right)
    Obtains an immutable triple of three non-null objects inferring the generic types.
    Type Parameters:
      `L` - the left element type.
      `M` - the middle element type.
      `R` - the right element type.
    Parameters:
      `left` - the left element, may not be null.
      `middle` - the middle element, may not be null.
      `right` - the right element, may not be null.
    Returns:
      an immutable triple formed from the three parameters, not null.
    Throws:
      `NullPointerException` - if any input is null.
    Since:
      3.13.0

  - ### compareTo

    public int compareTo(Triple<L,M,R> other)
    Compares the triple based on the left element, followed by the middle element, finally the right element. The types must be `Comparable`.
    Specified by:
      `compareTo` in interface `Comparable<L>`
    Parameters:
      `other` - the other triple, not null.
    Returns:
      negative if this is less, zero if equal, positive if greater.

  - ### equals

    public boolean equals(Object obj)
    Compares this triple to another based on the three elements.
    Overrides:
      `equals` in class `Object`
    Parameters:
      `obj` - the object to compare to, null returns false.
    Returns:
      true if the elements of the triple are equal.

  - ### getLeft

    public abstract L getLeft()
    Gets the left element from this triple.
    Returns:
      the left element, may be null.

  - ### getMiddle

    public abstract M getMiddle()
    Gets the middle element from this triple.
    Returns:
      the middle element, may be null.

  - ### getRight

    public abstract R getRight()
    Gets the right element from this triple.
    Returns:
      the right element, may be null.

  - ### hashCode

    public int hashCode()
    Returns a suitable hash code.

    The hash code is adapted from the definition in `Map.Entry`.

    Overrides:
      `hashCode` in class `Object`
    Returns:
      the hash code.

  - ### toString

    public String toString()
    Returns a String representation of this triple using the format `(left,middle,right)`.
    Overrides:
      `toString` in class `Object`
    Returns:
      a string describing this object, not null.

  - ### toString

    public String toString(String format)
    Formats the receiver using the given format.

    This uses `Formattable` to perform the formatting. Three variables may be used to embed the left and right elements. Use `%1$s` for the left element, `%2$s` for the middle and `%3$s` for the right element. The default format used by `toString()` is `(%1$s,%2$s,%3$s)`.

    Parameters:
      `format` - the format string, optionally containing `%1$s`, `%2$s` and `%3$s`, not null.
    Returns:
      the formatted string, not null.