uk.ac.starlink.vo

Class Tree<T>

java.lang.Object

uk.ac.starlink.vo.Tree<T>

Direct Known Subclasses:

Tree.Branch, Tree.Leaf

public abstract class Tree<T>
extends Object

Hierarchical data structure suitable for general use. All instances of this class are either of class Tree.Leaf or Tree.Branch.

Node might be a better name than Tree, but since it's used with DOM parsing I want to avoid a name clash with org.w3c.dom.Node.

Since:

19 Jan 2023

Author:

Mark Taylor

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Tree.Branch<T> Tree instance that contains a list of children and no referenced item.
static class	Tree.Leaf<T> Tree instance that contains a referenced item and no children.

Method Summary

Modifier and Type	Method and Description
abstract Tree.Branch<T>	asBranch() Returns this instance as a Branch if it's a branch, or null if it's a leaf.
abstract Tree.Leaf<T>	asLeaf() Returns this instance as a Leaf if it's a leaf, or null if it's a branch.
abstract boolean	isLeaf() Returns true if this instance is a Leaf, false if it's a Branch.
abstract <R> Tree<R>	map(java.util.function.Function<T,R> mapping) Recursively converts this Tree to one with the same structure, but with the leaf items mapped from their existing values to new values determined by a supplied mapping function.

Methods inherited from class java.lang.Object

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

Method Detail

isLeaf

public abstract boolean isLeaf()

Returns true if this instance is a Leaf, false if it's a Branch.

Returns:

true iff this is a leaf

asLeaf

public abstract Tree.Leaf<T> asLeaf()

Returns this instance as a Leaf if it's a leaf, or null if it's a branch.

Returns:

this cast to Leaf, or null

asBranch

public abstract Tree.Branch<T> asBranch()

Returns this instance as a Branch if it's a branch, or null if it's a leaf.

Returns:

this cast to Branch, or null

map

public abstract <R> Tree<R> map(java.util.function.Function<T,R> mapping)

Recursively converts this Tree to one with the same structure, but with the leaf items mapped from their existing values to new values determined by a supplied mapping function.

Parameters:

mapping - mapping function

Returns:

tree with mapped values