Tree (ANTLR 4 Runtime 4.13.1 API)

All Known Subinterfaces:

ErrorNode, ParseTree, RuleNode, SyntaxTree, TerminalNode

All Known Implementing Classes:

ErrorNodeImpl, InterpreterRuleContext, ParserRuleContext, RuleContext, RuleContextWithAltNum, TerminalNodeImpl
```
public interface Tree
```
The basic notion of a tree has a parent, a payload, and a list of children. It is the most abstract interface for all the trees used by ANTLR.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Tree`	`getChild(int i)`	If there are children, get the `i`th value indexed from 0.
`int`	`getChildCount()`	How many children are there? If there is none, then this node represents a leaf node.
`Tree`	`getParent()`	The parent of this node.
`Object`	`getPayload()`	This method returns whatever object represents the data at this node.
`String`	`toStringTree()`	Print out a whole tree, not just a node, in LISP format `(root child1 .. childN)`.

- Method Detail
  - getParent
```
Tree getParent()
```
    The parent of this node. If the return value is null, then this node is the root of the tree.
  - getPayload
```
Object getPayload()
```
    This method returns whatever object represents the data at this node. For example, for parse trees, the payload can be a Token representing a leaf node or a RuleContext object representing a rule invocation. For abstract syntax trees (ASTs), this is a Token object.
  - getChild
```
Tree getChild(int i)
```
    If there are children, get the ith value indexed from 0.
  - getChildCount
```
int getChildCount()
```
    How many children are there? If there is none, then this node represents a leaf node.
  - toStringTree
```
String toStringTree()
```
    Print out a whole tree, not just a node, in LISP format (root child1 .. childN). Print just a node if this is a leaf.