Tree

This is a fork of nicmart/tree php tree structure. It is used for personal projects.

In Tree you can find a basic but flexible tree data structure for php together with and an handful Builder class, that enables you to build tree in a fluent way.

This package adds a Tree container which encapsulates the Nodes.

The tree data structure

The Tree\Node\NodeInterface interface abstracts the concept of a tree node. In Tree a Node has essentially two things: a set of children (that implements the same NodeInterface interface) and a value.

On the other hand, the Tree\Node\Node gives a straight implementation for that interface.

Creating a node

useTree\Node\Node;
$node = newNode('foo');

Getting and setting the value of a node

Each node has a value property, that can be any php value.

$node->setValue('my value');
echo$node->getValue(); //Prints 'my value'

Adding one or more children

$child1 = newNode('child1');
$child2 = newNode('child2');
$node
->addChild($child1)
->addChild($child2);

Removing a child

$node->removeChild($child1);

Getting the array of all children

$children = $node->getChildren();

Overwriting the children set

$node->setChildren([newNode('foo'), newNode('bar')]);

Removing all children

$node->removeAllChildren();

Getting if the node is a leaf or not

A leaf is a node with no children.

$node->isLeaf();

Getting if the node is a child or not

A child is a node that has a parent.

$node->isChild();

Getting the parent of a node

Reference to the parent node is automatically managed by child-modifiers methods

$root->addChild($node = newNode('child'));
$node->getParent(); // Returns $root

Getting the ancestors of a node

$root = (newNode('root'))
->addChild($child = newNode('child'))
->addChild($grandChild = newNode('grandchild'))
;
$grandchild->getAncestors(); // Returns [$root, $child]

Related Methods

• getAncestorsAndSelf retrieves ancestors of a node with the current node included.

Getting the root of a node

$root = $node->root();

Getting the neighbors of a node

$root = (newNode('root'))
->addChild($child1 = newNode('child1'))
->addChild($child2 = newNode('child2'))
->addChild($child3 = newNode('child3'))
;
$child2->getNeighbors(); // Returns [$child1, $child3]

Related Methods

• getNeighborsAndSelf retrieves neighbors of current node and the node itself.

Getting the depth of a node

$node->getDepth();

Getting the height of a node

$node->getHeight();

The Builder

The builder provides a convenient way to build trees. It is provided by the Builder class, but you can implement your own builder making an implementation of the BuilderInterfaceclass.

Example

Let's see how to build the following tree, where the nodes label are represents nodes values:

 A
/ \
B C
/|\
D E F
/|
G H 

And here is the code:

$builder = newTree\Builder\NodeBuilder;
$builder
->value('A')
->leaf('B')
->tree('C')
->tree('D')
->leaf('G')
->leaf('H')
->end()
->leaf('E')
->leaf('F')
->end()
;
$nodeA = $builder->getNode();

The example should be self-explanatory, but here you are a brief description of the methods used above.

Builder::value($value)

Set the value of the current node to $value

Builder::leaf($value)

Add to the current node a new child whose value is $value.

Builder::tree($value)

Add to the current node a new child whose value is $value, and set the new node as the builder current node.

Builder::end()

Returns to the context the builder was before the call to treemethod, i.e. make the builder go one level up.

Builder::getNode()

Returns the current node.

Yield of a tree

You can obtain the yield of a tree (i.e. the list of leaves in a preorder traversal) using the YieldVisitor. For example, if $node is the tree builded above, then

useTree\Visitor\YieldVisitor;
$visitor = newYieldVisitor;
$yield = $node->accept($visitor);
// $yield will contain nodes B, G, H, E, F

Tests

phpunit