Small library for a basic but very flexible tree data structure. You have the possibility to sort tree nodes and control the payload type within the tree nodes.

Overview

The interface TreeNodes\TreeNode is the most basic abstract concept of a tree node. A tree is seen as a set of TreeNode objects which may or may not have a set of children (which are objects implementing the interface TreeNodes\TreeNode) and a payload (can be a simple integer or boolean or a complex object).
We offer different kind of tree nodes. Choose one which fits your use-case the best.

Tree Node types

• TreeNode
• TypedPayloadTreeNode
• SortableTreeNode
• TypedPayloadSortableTreeNode

For each type a generic implementation class exists, e.g. TreeNodes\GenericTreeNode is a basic implementation of the interface TreeNodes\TreeNode.

Install

Best way to get started is to use Composer.

composer require dynamic-commerce/tree-nodes

Basic usage

In the following examples we use the following example tree structure:

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

Id Generator

Each tree node has a id property. To generate this id, you can specify your own IdGenerator using the interface TreeNodes\IdGenerator. If you want to use the default, just pass null as value to the constructor. Default case uses the TreeNodes\GenericIdGenerator to generate a v4 UUID.

Create a new TreeNode

use TreeNodes\GenericTreeNode;
$treeNode = new GenericTreeNode('Root');

The interface TreeNodes\TypedPayloadTreeNode offers a set of payload types as public constants you can use to restrict the type of the payload.

use TreeNodes\GenericTypedPayloadTreeNode;
use TreeNodes\TypedPayloadTreeNode;
$treeNode = new GenericTypedPayloadTreeNode('Root', TypedPayloadTreeNode::PAYLOAD_TYPE_STRING, null);

If you want to have a object as payload to just be a specific class you can simply provide the FQDN.

use TreeNodes\GenericTypedPayloadTreeNode;
use TreeNodes\TypedPayloadTreeNode;
$myObject = new MyObject();
$treeNode = new GenericTypedPayloadTreeNode($myObject, TypedPayloadTreeNode::PAYLOAD_TYPE_OBJECT_WITH_FQDN,MyObject::class);

Adding children

use TreeNodes\GenericTreeNode;
$rootTreeNode = new GenericTreeNode('Root');
$treeNodeA = new GenericTreeNode('A');
$rootTreeNode->addChild($treeNodeA);

TreeNodes with sorting

When you add a new sortable child the sorting will be calculated and set to the next highest sorting of the current children within the current parent node.

use TreeNodes\GenericSortableTreeNode;
$rootTreeNode = new GenericSortableTreeNode('Root');
$treeNodeA = new GenericSortableTreeNode('A');
$rootTreeNode->addChildWithSorting($treeNodeA);
echo $treeNodeA->getPerLevelSorting(); //Prints 1 (first child for current parent node)
$treeNodeB = new GenericSortableTreeNode('B');
$rootTreeNode->addChildWithSorting($treeNodeB);
echo $treeNodeB->getPerLevelSorting(); //Prints 2 (second child for current parent node)

When you want to change the sorting of a tree node you can simply request it. Use the static method processNewSortingRequest providing the node you want to move and the new sorting.

//assume we want to move `$treeNodeB` to sorting 1
GenericSortableTreeNode::processNewSortingRequest($treeNodeB, 1);
echo $treeNodeA->getPerLevelSorting(); //Prints 2 now (automatically changed within the sort request)
echo $treeNodeB->getPerLevelSorting(); //Prints 1 now

Not only can you change the sorting within a tree node children you can even move a node with all it’s children to a new position. To do that you can use the static method processMoveRequest providing the node you want to move, the new parent node e.g. Root and the new sorting it should have.

use TreeNodes\GenericSortableTreeNode;
$rootTreeNode = new GenericSortableTreeNode('Root');
$treeNodeA = new GenericSortableTreeNode('A');
$treeNodeB = new GenericSortableTreeNode('B');
$treeNodeC = new GenericSortableTreeNode('C');
$treeNodeD = new GenericSortableTreeNode('D');
$treeNodeE = new GenericSortableTreeNode('E');
$treeNodeF = new GenericSortableTreeNode('F');
$treeNodeG = new GenericSortableTreeNode('G');
$rootTreeNode->addChildWithSorting($treeNodeA);
$rootTreeNode->addChildWithSorting($treeNodeB);
$treeNodeA->addChildWithSorting($treeNodeC);
$treeNodeA->addChildWithSorting($treeNodeD);
$treeNodeC->addChildWithSorting($treeNodeE);
$treeNodeC->addChildWithSorting($treeNodeF);
$treeNodeC->addChildWithSorting($treeNodeG);
//assume we want to move C (with all children E,F,G) to new parent node Root and sorting 2.
GenericSortableTreeNode::processMoveRequest($treeNodeC,$rootTreeNode,2);
echo $treeNodeC->getParent()->getPayload(); //Prints Root
echo $treeNodeC->getLevel(); //Prints 1
echo $treeNodeC->getPerLevelSorting(); //Prints 2

You can implement your own classes for handling sort and move requests. Simple use the interface TreeNodes\TreeNodeSortRequestProcessor and the trait TreeNodes\canProcessTreeNodeSortRequests.

Remove a child

use TreeNodes\GenericTreeNode;
$rootTreeNode = new GenericTreeNode('Root');
$treeNodeA = new GenericTreeNode('A');
$rootTreeNode->addChild($treeNodeA);
echo $rootTreeNode->getNoOfChildren(); //Prints 1
$rootTreeNode->removeChild($treeNodeA);
echo $rootTreeNode->getNoOfChildren(); //Prints 0

Same as with adding children you can remove the children with different types by using separate functions

use TreeNodes\GenericSortableTreeNode;
$rootTreeNode = new GenericSortableTreeNode('Root');
$treeNodeA = new GenericSortableTreeNode('A');
$rootTreeNode->addChildWithSorting($treeNodeA);
echo $rootTreeNode->getNoOfChildrenWithSorting(); //Prints 1
$rootTreeNode->removeChildWithSorting($treeNodeA);
echo $rootTreeNode->getNoOfChildrenWithSorting(); //Prints 0

Testing

We use PHPUnit to automate testing and to detect issues. All unit tests are located in the /tests folder. If you want to run them use the pre configured phpunit.xml and run ./vendor/bin/phpunit -c phpunit.xml in your preferred CMD.