DataTree

A fully functional tree library which includes list, set and map trees, printers to print a tree as Text, HTML or CSV, iterators and much more

---

 

---

The project is separated in four packages:

• The base package datatree: These tree implementations are the main implementations to use. See the various tree implementations below.
• The sub-package datatree.core: The core package contains the basic structures on which the main implementations are built up on. The most important class here is CollectionTreeNodeInterface, because this is the base of every tree node implementation. Each tree implementation consists of an interface and an abstract implementation.
• The sub-package datatree.printer: The printer package offers a set of printers which can be used to print the tree structures of this project in various formats (currently HTML, CSV, text), but it also allows any tree-like structure to be printed.
• The sub-package datatree.onoff: Special implementations of the tree which support ignoring (no printing) and hiding (collapsing) of tree nodes.

Tree implementations:

• KeyListTreeNode: A tree in which the nodes can be accessed though a key or though their index. The nodes are stored in an ordered list.
• KeySetTreeNode: A tree in which the nodes can be accessed though a key. The nodes are unordered in a set.
• ListTreeNode: A tree in which the nodes are stored in an ordered list. The nodes can only be accessed through their index.
• SetTreeNode: A tree in which the nodes are unordered in a set. The nodes can only be accessed by using an iterator.

All tree implementations implement the Iterator interface. A call to iterator() returns an TreeIterator. All list tree implementations (list and keylist) also implement the ListIterator interface in addition to the Iterator interface. The method listIterator() returns a ListTreeIterator which supports more advanced iteration (forward, backwards, peek).

Tree examples

Tree printer implementations

• TreeNodePlainTextPrinter: Prints a tree in plain text (see example below)
• TreeNodeDebutPrinter: Prints a tree in plain text, formatted with additional node information to analyze and debug a tree (e.g. line number, child index, node depth, node key and value, ...)
• TreeNodeCSVPrinter: Prints a tree in the CSV format to be used in any spreadsheet program (e.g. Excel, LibreOffice/OpenOffice Calc, ...). The tree structure and the values are aligned in columns for spreadsheet usability.
• TreeNodeHTMLPrinter: Prints the tree as HTML table to be displayed in a web browser. Various formatting (color, size, ...) options are built in.

Here is an example of a tree (as used in the JUnit test cases). This tree is printed using the built in plain text tree printer.

Tree
├─ Child 1
│  ├─ Child 1.1
│  └─ Child 1.2
├─ Child 2
│  ├─ Child 2.1
│  ├─ Child 2.2
│  │  ├─ Child 2.2.1
│  │  └─ Child 2.2.2
│  │     └─ Child 2.2.2.1
│  ├─ Child 2.3
│  └─ Child 2.4
│     └─ Child 2.4.1
├─ Child 3
│  ├─ Child 3.1
│  └─ Child 3.2
└─ Child 4
   └─ Child 4.1
      └─ Child 4.2

Tree printer examples

---

OnOff tree

This is a special implementation of the tree, built on top of the regular data tree. It offers additional functionality to control the appearance of nodes in the tree. Features are:

• Hiding a node: A hidden node does not show up in the tree, which also means that all its child nodes are not visible in the tree
• Ignoring a node: An ignored node is skipped when traveling through the tree. This means that all its child nodes will appear as child nodes of its parent node.
• Hiding child nodes: Only the child nodes of a node do not appear in the tree. The node itself stays visible.
• Force visibility: Overwrites/ignores any state set with the previous three functions.

OnOff tree examples

---

This project can be built with Maven

Maven command:

$ mvn clean install

pom.xml entry in your project:

<dependency>
	<groupId>ch.thn</groupId>
	<artifactId>datatree</artifactId>
	<version>0.0.1-SNAPSHOT</version>
</dependency>

---