com.github.javaparser.ast

Class Node

java.lang.Object

com.github.javaparser.ast.Node

All Implemented Interfaces:

NodeWithRange<Node>, Observable, Visitable, HasParentNode<Node>, Cloneable

Direct Known Subclasses:

ArrayCreationLevel, BodyDeclaration, CatchClause, Comment, CompilationUnit, Expression, ImportDeclaration, MemberValuePair, ModuleDeclaration, ModuleStmt, Name, PackageDeclaration, Parameter, SimpleName, Statement, Type, VariableDeclarator

public abstract class Node
extends Object
implements Cloneable, HasParentNode<Node>, Visitable, NodeWithRange<Node>

Base class for all nodes of the abstract syntax tree.

Construction

The tree is built by instantiating the required nodes, then adding them to other nodes. If it is the parser who is building the tree, it will use the largest constructor, the one with "range" as the first parameter. If you want to manually instantiate nodes, we suggest to...

• use a convenience method, like "addStatement(...)", or if none are available...
• use a convenient constructor, like ClassOrInterfaceType(String name), or if none are available...
• use the default constructor.
• Alternatively, use one of the JavaParser.parse(snippet) methods.

... and use the various methods on the node to initialize it further, if needed.

Parent/child

The parent node field is managed automatically and can be seen as read only. Note that there is only one parent, and trying to use the same node in two places will lead to unexpected behaviour. It is advised to clone() a node before moving it around.

Comments

Each Node can have one associated comment which describes it and a number of "orphan comments" which it contains but are not specifically associated to any child.

Positions

When the parser creates nodes, it sets their source code position in the "range" field. When you manually instantiate nodes, their range is not set. The top left character is position 1, 1. Note that since this is an abstract syntax tree, it leaves out a lot of text from the original source file, like where braces or comma's are exactly. Therefore there is no position information on everything in the original source file.

Observers

It is possible to add observers to the the tree. Any change in the tree is sent as an event to any observers watching.

Visitors

The most comfortable way of working with an abstract syntax tree is using visitors. You can use one of the visitors in the visitor package, or extend one of them. A visitor can be "run" by calling accept on a node:

node.accept(visitor, argument);

where argument is an object of your choice (often simply null.)

Author:

Julio Vilmar Gesser

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Node.ObserverRegistrationMode Different registration mode for observers on nodes.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ABSOLUTE_BEGIN_LINE
static int	ABSOLUTE_END_LINE
static Comparator<NodeWithRange<?>>	NODE_BY_BEGIN_POSITION This can be used to sort nodes on position.
protected static PrettyPrinterConfiguration	prettyPrinterNoCommentsConfiguration

Constructor Summary

Constructors

Constructor and Description
Node(Range range)

Method Summary

Modifier and Type	Method and Description
void	addOrphanComment(Comment comment)
Node	clone()
protected void	customInitialization() Called in every constructor for node specific code.
boolean	equals(Object obj)
List<Comment>	getAllContainedComments() This is the list of Comment which are contained in the Node either because they are properly associated to one of its children or because they are floating around inside the Node
List<Node>	getChildNodes() Contains all nodes that have this node set as their parent.
<N extends Node> List<N>	getChildNodesByType(Class<N> clazz) Recursively finds all nodes of a certain type.
Optional<Comment>	getComment() This is a comment associated with this node.
<M> M	getData(DataKey<M> key) Gets data for this component using the given key.
NodeMetaModel	getMetaModel()
List<NodeList<?>>	getNodeLists() The list of NodeLists owned by this node.
<N extends Node> List<N>	getNodesByType(Class<N> clazz) Deprecated. use getChildNodesByType
List<Comment>	getOrphanComments() This is a list of Comment which are inside the node and are not associated with any meaningful AST Node.
Optional<Node>	getParentNode() Return the parent node or null, if no parent is set.
Node	getParentNodeForChildren() this for everything except NodeLists.
Optional<Range>	getRange()
boolean	hasComment() Deprecated. use getComment().isPresent()
int	hashCode()
boolean	isRegistered(AstObserver observer) Was this observer registered? Note that equals is used to determine if the given observer was registered.
<P> void	notifyPropertyChange(ObservableProperty property, P oldValue, P newValue)
void	register(AstObserver observer) Register an observer.
void	register(AstObserver observer, Node.ObserverRegistrationMode mode) Register a new observer for the given node.
void	registerForSubtree(AstObserver observer) Register the observer for the current node and all the contained node and nodelists, recursively.
boolean	remove() Try to remove this node from the parent
boolean	remove(Node node)
Node	removeComment()
void	removeForced() Forcibly removes this node from the AST.
boolean	removeOrphanComment(Comment comment)
protected void	setAsParentNodeOf(NodeList<? extends Node> list)
Node	setBlockComment(String comment) Use this to store additional information to this node.
Node	setComment(Comment comment) Use this to store additional information to this node.
<M> void	setData(DataKey<M> key, M object) Sets data for this component using the given key.
Node	setLineComment(String comment) Use this to store additional information to this node.
Node	setParentNode(Node parentNode) Assign a new parent to this node, removing it from the list of children of the previous parent, if any.
Node	setRange(Range range)
String	toString() Return the String representation of this node.
String	toString(PrettyPrinterConfiguration prettyPrinterConfiguration)
void	tryAddImportToParentCompilationUnit(Class<?> clazz)
void	unregister(AstObserver observer) Unregister an observer.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.github.javaparser.HasParentNode

getAncestorOfType, setAsParentNodeOf, setAsParentNodeOf

Methods inherited from interface com.github.javaparser.ast.visitor.Visitable

accept, accept

Methods inherited from interface com.github.javaparser.ast.nodeTypes.NodeWithRange

containsWithin, getBegin, getEnd, isPositionedAfter, isPositionedBefore

Field Detail

NODE_BY_BEGIN_POSITION

public static Comparator<NodeWithRange<?>> NODE_BY_BEGIN_POSITION

This can be used to sort nodes on position.

prettyPrinterNoCommentsConfiguration

protected static final PrettyPrinterConfiguration prettyPrinterNoCommentsConfiguration

ABSOLUTE_BEGIN_LINE

public static final int ABSOLUTE_BEGIN_LINE

See Also:

Constant Field Values

ABSOLUTE_END_LINE

public static final int ABSOLUTE_END_LINE

See Also:

Constant Field Values

Constructor Detail

Node

public Node(Range range)

Method Detail

customInitialization

protected void customInitialization()

Called in every constructor for node specific code. It can't be written in the constructor itself because it will be overwritten during code generation.

getComment

@Generated(value="com.github.javaparser.generator.core.node.PropertyGenerator")
public Optional<Comment> getComment()

This is a comment associated with this node.

Returns:

comment property

getRange

public Optional<Range> getRange()

Specified by:

getRange in interface NodeWithRange<Node>

Returns:

the range of characters in the source code that this node covers.

setRange

public Node setRange(Range range)

Specified by:

setRange in interface NodeWithRange<Node>

Parameters:

range - the range of characters in the source code that this node covers. null can be used to indicate that no range information is known, or that it is not of interest.

setComment

public final Node setComment(Comment comment)

Use this to store additional information to this node.

Parameters:

comment - to be set

setLineComment

public final Node setLineComment(String comment)

Use this to store additional information to this node.

Parameters:

comment - to be set

setBlockComment

public final Node setBlockComment(String comment)

Use this to store additional information to this node.

Parameters:

comment - to be set

toString

public final String toString()

Return the String representation of this node.

Overrides:

toString in class Object

Returns:

the String representation of this node

toString

public final String toString(PrettyPrinterConfiguration prettyPrinterConfiguration)

hashCode

public final int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

getParentNode

public Optional<Node> getParentNode()

Description copied from interface: HasParentNode

Return the parent node or null, if no parent is set.

Specified by:

getParentNode in interface HasParentNode<Node>

getChildNodes

public List<Node> getChildNodes()

Contains all nodes that have this node set as their parent. You can add nodes to it by setting a node's parent to this node. You can remove nodes from it by setting a child node's parent to something other than this node.

Returns:

all nodes that have this node as their parent.

addOrphanComment

public void addOrphanComment(Comment comment)

removeOrphanComment

public boolean removeOrphanComment(Comment comment)

getOrphanComments

public List<Comment> getOrphanComments()

This is a list of Comment which are inside the node and are not associated with any meaningful AST Node.

For example, comments at the end of methods (immediately before the parenthesis) or at the end of CompilationUnit are orphan comments.

When more than one comment preceeds a statement, the one immediately preceding it it is associated with the statements, while the others are orphans.

Changes to this list are not persisted.

Returns:

all comments that cannot be attributed to a concept

getAllContainedComments

public List<Comment> getAllContainedComments()

This is the list of Comment which are contained in the Node either because they are properly associated to one of its children or because they are floating around inside the Node

Returns:

all Comments within the node as a list

setParentNode

public Node setParentNode(Node parentNode)

Assign a new parent to this node, removing it from the list of children of the previous parent, if any.

Specified by:

setParentNode in interface HasParentNode<Node>

Parameters:

parentNode - node to be set as parent

Returns:

return this

hasComment

@Deprecated
public boolean hasComment()

Deprecated. use getComment().isPresent()

tryAddImportToParentCompilationUnit

public void tryAddImportToParentCompilationUnit(Class<?> clazz)

getChildNodesByType

public <N extends Node> List<N> getChildNodesByType(Class<N> clazz)

Recursively finds all nodes of a certain type.

Parameters:

clazz - the type of node to find.

getNodesByType

@Deprecated
public <N extends Node> List<N> getNodesByType(Class<N> clazz)

Deprecated. use getChildNodesByType

getData

public <M> M getData(DataKey<M> key)

Gets data for this component using the given key.

Type Parameters:

M - The type of the data.

Parameters:

key - The key for the data

Returns:

The data or null of no data was found for the given key

See Also:

DataKey

setData

public <M> void setData(DataKey<M> key,
                        M object)

Sets data for this component using the given key. For information on creating DataKey, see DataKey.

Type Parameters:

M - The type of data

Parameters:

key - The singleton key for the data

object - The data object

See Also:

DataKey

remove

public boolean remove()

Try to remove this node from the parent

Returns:

true if removed, false if it is a required property of the parent, or if the parent isn't set.

Throws:

RuntimeException - if it fails in an unexpected way

removeForced

public void removeForced()

Forcibly removes this node from the AST. If it cannot be removed from the parent with remove(), it will try to remove its parent instead, until it finds a node that can be removed, or no parent can be found. Since everything at CompilationUnit level is removable, this method will only (silently) fail when the node is in a detached AST fragment.

getParentNodeForChildren

public Node getParentNodeForChildren()

Description copied from interface: HasParentNode

this for everything except NodeLists. NodeLists use their parent as their children parent.

Specified by:

getParentNodeForChildren in interface HasParentNode<Node>

setAsParentNodeOf

protected void setAsParentNodeOf(NodeList<? extends Node> list)

notifyPropertyChange

public <P> void notifyPropertyChange(ObservableProperty property,
                                     P oldValue,
                                     P newValue)

unregister

public void unregister(AstObserver observer)

Description copied from interface: Observable

Unregister an observer. If the given observer was not registered there are no effects.

Specified by:

unregister in interface Observable

register

public void register(AstObserver observer)

Description copied from interface: Observable

Register an observer.

Specified by:

register in interface Observable

register

public void register(AstObserver observer,
                     Node.ObserverRegistrationMode mode)

Register a new observer for the given node. Depending on the mode specified also descendants, existing and new, could be observed. For more details see ObserverRegistrationMode.

registerForSubtree

public void registerForSubtree(AstObserver observer)

Register the observer for the current node and all the contained node and nodelists, recursively.

isRegistered

public boolean isRegistered(AstObserver observer)

Description copied from interface: Observable

Was this observer registered? Note that equals is used to determine if the given observer was registered.

Specified by:

isRegistered in interface Observable

getNodeLists

public List<NodeList<?>> getNodeLists()

The list of NodeLists owned by this node.

remove

@Generated(value="com.github.javaparser.generator.core.node.RemoveMethodGenerator")
public boolean remove(Node node)

removeComment

@Generated(value="com.github.javaparser.generator.core.node.RemoveMethodGenerator")
public Node removeComment()

clone

@Generated(value="com.github.javaparser.generator.core.node.CloneGenerator")
public Node clone()

Overrides:

clone in class Object

getMetaModel

@Generated(value="com.github.javaparser.generator.core.node.GetMetaModelGenerator")
public NodeMetaModel getMetaModel()