Package it.tidalwave.util

Class Pair<A,B>

java.lang.Object

it.tidalwave.util.Pair<A,B>

@Immutable
public class Pair<A,B>
extends Object

A value object that contains a pair of values. Some factory methods allow creating pairs out of existing collections or arrays associating an index.

Since:

3.2-ALPHA-6

Author:

Fabrizio Giudici

Status: draft API

Field Summary

Fields

Modifier and Type	Field	Description
final A	a
final B	b
static final IntUnaryOperator	BASE_0	A base 0 index rebaser.
static final IntUnaryOperator	BASE_1	A base 1 index rebaser.

Constructor Summary

Constructors

Constructor	Description
Pair()

Method Summary

Modifier and Type	Method	Description
static <T> Stream<Pair<Integer,T>>	indexedPairStream(int from, int to, IntFunction<? extends T> valueSupplier)	Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(int from, int to, IntFunction<? extends T> valueSupplier, IntUnaryOperator rebaser)	Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value).
static <T, I> Stream<Pair<I,T>>	indexedPairStream(int from, int to, IntFunction<? extends T> valueSupplier, IntUnaryOperator rebaser, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(Iterable<? extends T> iterable)	Returns a Stream out of the elements in a given Iterable made of Pairs (index, value).
static <I, T> Stream<Pair<I,T>>	indexedPairStream(Iterable<? extends T> iterable, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements in a given Iterable made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(Iterable<? extends T> iterable, IntUnaryOperator rebaser)	Returns a Stream out of the elements in a given Iterable made of Pairs (index, value).
static <I, T> Stream<Pair<I,T>>	indexedPairStream(Iterable<? extends T> iterable, IntUnaryOperator rebaser, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements returned by an iterable, made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(Stream<? extends T> stream)	Returns a Stream out of the elements in a given Stream made of Pairs (index, value).
static <I, T> Stream<Pair<I,T>>	indexedPairStream(Stream<? extends T> stream, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements in a given Stream made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(Stream<? extends T> stream, IntUnaryOperator rebaser)	Returns a Stream out of the elements in a given Stream made of Pairs (index, value).
static <I, T> Stream<Pair<I,T>>	indexedPairStream(Stream<? extends T> stream, IntUnaryOperator rebaser, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements returned by a Stream, made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(T[] array)	Returns a Stream out of the elements in a given array made of Pairs (index, value).
static <I, T> Stream<Pair<I,T>>	indexedPairStream(T[] array, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements in a given array made of Pairs (index, value).
static <T> Stream<Pair<Integer,T>>	indexedPairStream(T[] array, IntUnaryOperator rebaser)	Returns a Stream out of the elements in the array, made of Pairs (index, value).
static <T, I> Stream<Pair<I,T>>	indexedPairStream(T[] array, IntUnaryOperator rebaser, IntFunction<? extends I> indexTransformer)	Returns a Stream out of the elements in the array, made of Pairs (index, value).
static <T> Stream<Pair<T,Integer>>	pairRange(T value, int from, int to)	Creates a Stream of Pairs composed of a given fixed value and an integer in the given range.
static <T> Stream<Pair<T,Integer>>	pairRangeClosed(T value, int from, int to)	Creates a Stream of Pairs composed of a given fixed value and an integer in the given range.
static <A, B> Collector<Pair<A,B>,?,Map<A,B>>	pairsToMap()	A Collector that produces a Map whose key is field a and value field b.
static <T, U> Stream<Pair<T,U>>	pairStream(T value, Stream<? extends U> stream)	Creates a Stream of Pairs composed of a given fixed value and another element taken from another Stream.
static <A, B> Stream<Pair<A,B>>	zip(Stream<? extends A> streamA, Stream<? extends B> streamB)	Zips two streams into a stream of Pairs.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

BASE_0

public static final IntUnaryOperator BASE_0

A base 0 index rebaser.

BASE_1

public static final IntUnaryOperator BASE_1

A base 1 index rebaser.

a

@Nonnull
public final A a

b

@Nonnull
public final B b

Constructor Details

Pair

public Pair()

Method Details

pairStream

@Nonnull
public static <T,
U> Stream<Pair<T,U>> pairStream(@Nonnull
 T value,
 @Nonnull
 Stream<? extends U> stream)

Creates a Stream of Pairs composed of a given fixed value and another element taken from another Stream.

Type Parameters:

T - the type of the value

U - the type of the Stream

Parameters:

value - the value

stream - the Stream

Returns:

the Stream of Pairs

Since:

3.2-ALPHA-12

pairRange

@Nonnull
public static <T> Stream<Pair<T,Integer>> pairRange(@Nonnull
 T value,
 @Nonnegative
 int from,
 @Nonnegative
 int to)

Creates a Stream of Pairs composed of a given fixed value and an integer in the given range.

Type Parameters:

T - the type of the value

Parameters:

value - the value

from - the first value of the integer Stream (included)

to - the last value of the integer Stream (excluded)

Returns:

the Stream of Pairs

Since:

3.2-ALPHA-12

pairRangeClosed

@Nonnull
public static <T> Stream<Pair<T,Integer>> pairRangeClosed(@Nonnull
 T value,
 @Nonnegative
 int from,
 @Nonnegative
 int to)

Creates a Stream of Pairs composed of a given fixed value and an integer in the given range.

Type Parameters:

T - the type of the value

Parameters:

value - the value

from - the first value of the integer Stream (included)

to - the last value of the integer Stream (included)

Returns:

the Stream of Pairs

Since:

3.2-ALPHA-12

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 T[] array)

Returns a Stream out of the elements in a given array made of Pairs (index, value).

Type Parameters:

T - the type of the elements

Parameters:

array - the array

Returns:

the stream

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 T[] array,
 @Nonnull
 IntUnaryOperator rebaser)

Returns a Stream out of the elements in the array, made of Pairs (index, value). The index can be rebased.

Type Parameters:

T - the type of the elements

Parameters:

array - the array

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

Returns:

the stream

indexedPairStream

@Nonnull
public static <I,
T> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 T[] array,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements in a given array made of Pairs (index, value). The index is transformed with the given function.

Type Parameters:

I - the type of the transformed index

T - the type of the elements

Parameters:

array - the array

indexTransformer - the transformer of the index

Returns:

the stream

indexedPairStream

@Nonnull
public static <T,
I> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 T[] array,
 @Nonnull
 IntUnaryOperator rebaser,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements in the array, made of Pairs (index, value). The index can be rebased and transformed with specific functions.

Type Parameters:

T - the type of the elements

I - the type of the transformed index

Parameters:

array - the array

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

indexTransformer - the transformer of the index

Returns:

the stream

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 Iterable<? extends T> iterable)

Returns a Stream out of the elements in a given Iterable made of Pairs (index, value).

Type Parameters:

T - the type of the elements

Parameters:

iterable - the iterable

Returns:

the stream

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 Iterable<? extends T> iterable,
 @Nonnull
 IntUnaryOperator rebaser)

Returns a Stream out of the elements in a given Iterable made of Pairs (index, value). The index can be rebased.

Type Parameters:

T - the type of the elements

Parameters:

iterable - the iterable

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

Returns:

the stream

indexedPairStream

@Nonnull
public static <I,
T> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 Iterable<? extends T> iterable,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements in a given Iterable made of Pairs (index, value). The index is transformed with the given function.

Type Parameters:

I - the type of the transformed index

T - the type of the elements

Parameters:

iterable - the iterable

indexTransformer - the transformer of the index

Returns:

the stream

indexedPairStream

@Nonnull
public static <I,
T> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 Iterable<? extends T> iterable,
 @Nonnull
 IntUnaryOperator rebaser,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements returned by an iterable, made of Pairs (index, value). The index is rebased and transformed with specific functions.

Type Parameters:

I - the type of the transformed index

T - the type of the elements

Parameters:

iterable - the iterable

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

indexTransformer - the transformer of the index

Returns:

the stream

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 Stream<? extends T> stream)

Returns a Stream out of the elements in a given Stream made of Pairs (index, value).

Type Parameters:

T - the type of the elements

Parameters:

stream - the stream

Returns:

the stream

Since:

3.2-ALPHA-12

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnull
 Stream<? extends T> stream,
 @Nonnull
 IntUnaryOperator rebaser)

Returns a Stream out of the elements in a given Stream made of Pairs (index, value). The index can be rebased.

Type Parameters:

T - the type of the elements

Parameters:

stream - the stream

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

Returns:

the stream

Since:

3.2-ALPHA-12

indexedPairStream

@Nonnull
public static <I,
T> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 Stream<? extends T> stream,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements in a given Stream made of Pairs (index, value). The index is transformed with the given function.

Type Parameters:

I - the type of the transformed index

T - the type of the elements

Parameters:

stream - the stream

indexTransformer - the transformer of the index

Returns:

the stream

Since:

3.2-ALPHA-12

indexedPairStream

@Nonnull
public static <I,
T> Stream<Pair<I,T>> indexedPairStream(@Nonnull
 Stream<? extends T> stream,
 @Nonnull
 IntUnaryOperator rebaser,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements returned by a Stream, made of Pairs (index, value). The index is rebased and transformed with specific functions.

Type Parameters:

I - the type of the transformed index

T - the type of the elements

Parameters:

stream - the stream

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

indexTransformer - the transformer of the index

Returns:

the stream

Since:

3.2-ALPHA-12

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnegative
 int from,
 @Nonnegative
 int to,
 @Nonnull
 IntFunction<? extends T> valueSupplier)

Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value).

Type Parameters:

T - the type of the elements

Parameters:

from - the first index (included)

to - the last index (excluded)

valueSupplier - the supplier of values

Returns:

the stream

indexedPairStream

@Nonnull
public static <T> Stream<Pair<Integer,T>> indexedPairStream(@Nonnegative
 int from,
 @Nonnegative
 int to,
 @Nonnull
 IntFunction<? extends T> valueSupplier,
 @Nonnull
 IntUnaryOperator rebaser)

Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value).

Type Parameters:

T - the type of the elements

Parameters:

from - the first index (included)

to - the last index (excluded)

valueSupplier - the supplier of values

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

Returns:

the stream

indexedPairStream

@Nonnull
public static <T,
I> Stream<Pair<I,T>> indexedPairStream(@Nonnegative
 int from,
 @Nonnegative
 int to,
 @Nonnull
 IntFunction<? extends T> valueSupplier,
 @Nonnull
 IntUnaryOperator rebaser,
 @Nonnull
 IntFunction<? extends I> indexTransformer)

Returns a Stream out of the elements returned by a supplier, made of Pairs (index, value). The index can be rebased and transformed with specific functions.

Type Parameters:

T - the type of the elements

I - the type of the transformed index

Parameters:

from - the first index (included)

to - the last index (excluded)

valueSupplier - the supplier of values

rebaser - the rebaser of the index (BASE_0, BASE_1 or a similar function)

indexTransformer - the transformer of the index

Returns:

the stream

pairsToMap

@Nonnull
public static <A,
B>
Collector<Pair<A,B>,?,Map<A,B>> pairsToMap()

A Collector that produces a Map whose key is field a and value field b. Use with Stream.collect(Collector).

Type Parameters:

A - the type of the former element of the pair

B - the type of the latter element of the pair

Returns:

the Collector

zip

@Nonnull
public static <A,
B> Stream<Pair<A,B>> zip(@Nonnull
 Stream<? extends A> streamA,
 @Nonnull
 Stream<? extends B> streamB)

Zips two streams into a stream of Pairs.

Type Parameters:

A - the type of elements of the first Stream

B - the type of elements of the second Stream

Parameters:

streamA - the first Stream

streamB - the second Stream

Returns:

the zipped Stream

Since:

3.2-ALPHA-17 (since 3.2-ALPHA-12 was in StreamOperations