Package io.vavr.collection

Class Tree.Node<T>

java.lang.Object

io.vavr.collection.Tree.Node<T>

Type Parameters:

T - value type

All Implemented Interfaces:

Foldable<T>, Traversable<T>, Tree<T>, Value<T>, java.io.Serializable, java.lang.Iterable<T>

Enclosing interface:

Tree<T>

public static final class Tree.Node<T>
extends java.lang.Object
implements Tree<T>, java.io.Serializable

Represents a tree node.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	Tree.Node.SerializationProxy<T>	A serialization proxy which, in this context, is used to deserialize immutable nodes with final instance fields.

Nested classes/interfaces inherited from interface io.vavr.collection.Tree

Tree.Empty<T>, Tree.Node<T>, Tree.Order

Field Summary

Fields

Modifier and Type	Field	Description
private List<Tree.Node<T>>	children
private static long	serialVersionUID
private int	size
private T	value

Constructor Summary

Constructors

Constructor	Description
Node(T value, List<Tree.Node<T>> children)	Constructs a rose tree branch.

Method Summary

Modifier and Type	Method	Description
java.lang.String	draw()	Creates a neat 2-dimensional drawing of a tree.
private void	drawAux(java.lang.String indent, java.lang.StringBuilder builder)
boolean	equals(java.lang.Object o)	Determines whether this collection is equal to the given object.
List<Tree.Node<T>>	getChildren()	Returns the children of this tree.
T	getValue()	Gets the value of this tree.
int	hashCode()	Returns the hash code of this collection.
boolean	isEmpty()	Checks if this Traversable contains no elements.
boolean	isLeaf()	Checks if this Tree is a leaf.
T	last()	Returns the last element of this Traversable.
int	length()	Returns the number of elements in this Traversable.
private void	readObject(java.io.ObjectInputStream stream)	readObject method for the serialization proxy pattern.
java.lang.String	toLispString()	Creates a Lisp-like representation of this Tree.
private static java.lang.String	toLispString(Tree<?> tree)
java.lang.String	toString()	Clarifies that values have a proper toString() method implemented.
private java.lang.Object	writeReplace()	writeReplace method for the serialization proxy pattern.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.vavr.collection.Foldable

fold, reduce, reduceOption

Methods inherited from interface io.vavr.collection.Traversable

arrangeBy, average, containsAll, count, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, headOption, isOrdered, isSingleValued, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sum

Methods inherited from interface io.vavr.collection.Tree

branchCount, collect, distinct, distinctBy, distinctBy, drop, dropRight, dropUntil, dropWhile, filter, flatMap, foldRight, groupBy, grouped, hasDefiniteSize, head, init, initOption, isAsync, isBranch, isDistinct, isLazy, isSequential, isTraversableAgain, iterator, iterator, leafCount, map, mapTo, mapToVoid, nodeCount, orElse, orElse, partition, peek, reject, replace, replaceAll, retainAll, scan, scanLeft, scanRight, slideBy, sliding, sliding, span, stringPrefix, tail, tailOption, take, takeRight, takeUntil, takeWhile, transform, traverse, traverse, unzip, unzip3, values, values, zip, zipAll, zipWith, zipWithIndex, zipWithIndex

Methods inherited from interface io.vavr.Value

collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, out, out, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

value

private final T value

children

private final List<Tree.Node<T>> children

size

private final int size

Constructor Detail

Node

public Node(T value,
            List<Tree.Node<T>> children)

Constructs a rose tree branch.

Parameters:

value - A value.

children - A non-empty list of children.

Throws:

java.lang.NullPointerException - if children is null

java.lang.IllegalArgumentException - if children is empty

Method Detail

getChildren

public List<Tree.Node<T>> getChildren()

Description copied from interface: Tree

Returns the children of this tree.

Specified by:

getChildren in interface Tree<T>

Returns:

the tree's children

getValue

public T getValue()

Description copied from interface: Tree

Gets the value of this tree.

Specified by:

getValue in interface Tree<T>

Returns:

The value of this tree.

isEmpty

public boolean isEmpty()

Description copied from interface: Traversable

Checks if this Traversable contains no elements.

Specified by:

isEmpty in interface Traversable<T>

Specified by:

isEmpty in interface Value<T>

Returns:

true if empty, false otherwise

length

public int length()

Description copied from interface: Traversable

Returns the number of elements in this Traversable.

Equivalent to Traversable.size().

Specified by:

length in interface Traversable<T>

Returns:

the number of elements

isLeaf

public boolean isLeaf()

Description copied from interface: Tree

Checks if this Tree is a leaf. A tree is a leaf if it is a Node with no children. Because the empty tree is no Node, it is not a leaf by definition.

Specified by:

isLeaf in interface Tree<T>

Returns:

true if this tree is a leaf, false otherwise.

last

public T last()

Description copied from interface: Traversable

Returns the last element of this Traversable.

Specified by:

last in interface Traversable<T>

Returns:

the last element

equals

public boolean equals(java.lang.Object o)

Description copied from interface: Traversable

Determines whether this collection is equal to the given object.

In Vavr, there are four basic collection types:

• Seq – sequential elements
• Set – distinct elements
• Map – key-value pairs
• Multimap – keys mapped to multiple values

Two collections are considered equal if and only if:

• They are of the same collection type (Seq, Set, Map, Multimap)
• They contain the same elements
• For Seq, the element order is the same

For Map and Multimap, two entries (key1, value1) and (key2, value2) are equal if both their keys and values are equal.

Additional notes:

• No collection equals null (e.g., Queue(1) != null)
• Null elements are allowed and treated as expected (e.g., List(null, 1) == Stream(null, 1), HashMap((null,1)) == LinkedHashMap((null,1)))
• Element order matters only for Seq
• Other collection classes are equal if their types and elements (in iteration order) are equal
• Iterators are compared by reference only

Specified by:

equals in interface Traversable<T>

Specified by:

equals in interface Tree<T>

Specified by:

equals in interface Value<T>

Overrides:

equals in class java.lang.Object

Parameters:

o - the object to compare with, may be null

Returns:

true if the collections are equal according to the rules above, false otherwise

hashCode

public int hashCode()

Description copied from interface: Traversable

Returns the hash code of this collection.

Vavr distinguishes between collections with predictable iteration order (like Seq) and collections with arbitrary iteration order (like Set, Map, and Multimap). In all cases, the hash of an empty collection is defined as 1.

For collections with predictable iteration order, the hash is computed as:

 int hash = 1;
 for (T t : this) {
     hash = hash * 31 + Objects.hashCode(t);
 }
 

For collections with arbitrary iteration order, the hash is computed to be independent of element order:

 int hash = 1;
 for (T t : this) {
     hash += Objects.hashCode(t);
 }
 

Note that these algorithms may change in future Vavr versions. Hash codes are generally not cached, unlike size/length, because caching would increase memory usage due to persistent tree-based structures. Computing the hash code is linear in time, O(n). For frequently re-used collections (e.g., as HashMap keys), caching can be done externally using a wrapper, for example:

{@code
 public final class Hashed {
     private final K key;
     private final Lazy hashCode;

     public Hashed(K key) {
         this.key = key;
         this.hashCode = Lazy.of(() -> Objects.hashCode(key));
     }

     public K key() { return key; }

Specified by:

hashCode in interface Traversable<T>

Specified by:

hashCode in interface Tree<T>

Specified by:

hashCode in interface Value<T>

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code of this collection

toString

public java.lang.String toString()

Description copied from interface: Value

Clarifies that values have a proper toString() method implemented.

See Object.toString().

Specified by:

toString in interface Tree<T>

Specified by:

toString in interface Value<T>

Overrides:

toString in class java.lang.Object

Returns:

A String representation of this object

toLispString

public java.lang.String toLispString()

Description copied from interface: Tree

Creates a Lisp-like representation of this Tree.

Specified by:

toLispString in interface Tree<T>

Returns:

This Tree as Lisp-string, i.e. represented as list of lists.

draw

public java.lang.String draw()

Description copied from interface: Tree

Creates a neat 2-dimensional drawing of a tree. Unicode characters are used to draw node junctions.

Specified by:

draw in interface Tree<T>

Returns:

A nice string representation of the tree.

drawAux

private void drawAux(java.lang.String indent,
                     java.lang.StringBuilder builder)

toLispString

private static java.lang.String toLispString(Tree<?> tree)

writeReplace

@GwtIncompatible("The Java serialization protocol is explicitly not supported")
private java.lang.Object writeReplace()

writeReplace method for the serialization proxy pattern.

The presence of this method causes the serialization system to emit a SerializationProxy instance instead of an instance of the enclosing class.

Returns:

A SerializationProxy for this enclosing class.

readObject

@GwtIncompatible("The Java serialization protocol is explicitly not supported")
private void readObject(java.io.ObjectInputStream stream)
                 throws java.io.InvalidObjectException

readObject method for the serialization proxy pattern.

Guarantees that the serialization system will never generate a serialized instance of the enclosing class.

Parameters:

stream - An object serialization stream.

Throws:

java.io.InvalidObjectException - This method will throw with the message "Proxy required".