Package com.github.javaparser.ast

Class Node

java.lang.Object
com.github.javaparser.ast.Node
All Implemented Interfaces:
NodeWithRange<Node>, NodeWithTokenRange<Node>, Observable, Visitable, HasParentNode<Node>, Cloneable
Direct Known Subclasses:
ArrayCreationLevel, BodyDeclaration, CatchClause, Comment, CompilationUnit, Expression, ImportDeclaration, MemberValuePair, Modifier, ModuleDeclaration, ModuleDirective, Name, PackageDeclaration, Parameter, ReceiverParameter, SimpleName, Statement, SwitchEntry, Type, VariableDeclarator
public abstract class Node extends Object implements Cloneable, HasParentNode<Node>, Visitable, NodeWithRange<Node>, NodeWithTokenRange<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

  • Field Details

  • Constructor Details

  • Method Details

    • 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.

    • getPrinter

      protected Printer getPrinter()

    • getPrinter

      protected Printer getPrinter​(PrinterConfiguration configuration)

    • createDefaultPrinter

      protected Printer createDefaultPrinter()

    • createDefaultPrinter

      protected Printer createDefaultPrinter​(PrinterConfiguration configuration)

    • getDefaultPrinterConfiguration

      protected PrinterConfiguration getDefaultPrinterConfiguration()

    • getComment

      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.

    • getTokenRange

      public Optional<TokenRange> getTokenRange()
      Specified by:
      getTokenRange in interface NodeWithTokenRange<Node>
      Returns:
      the range of tokens that this node covers.

    • setTokenRange

      public Node setTokenRange​(TokenRange tokenRange)
      Specified by:
      setTokenRange in interface NodeWithTokenRange<Node>

    • 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 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()
      Overrides:
      toString in class Object
      Returns:
      pretty printed source code for this node and its children.

    • toString

      public final String toString​(PrinterConfiguration configuration)
      Returns:
      pretty printed source code for this node and its children. Formatting can be configured with parameter PrinterConfiguration.

    • 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
      Returns the parent node, or Optional.empty 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 and remove nodes from this list by adding or removing nodes from the fields of 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 newParentNode)
      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:
      newParentNode - node to be set as parent
      Returns:
      return this

    • setAsParentNodeOf

      protected void setAsParentNodeOf​(Node childNode)

    • tryAddImportToParentCompilationUnit

      public void tryAddImportToParentCompilationUnit​(Class<?> clazz)

    • getChildNodesByType

      @Deprecated public <N extends Node> List<N> getChildNodesByType​(Class<N> clazz)
      Deprecated.
      use findAll(Class) but be aware that findAll also considers the initial node.
      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 findAll(Class) but be aware that findAll also considers the initial node.

    • getData

      public <M> M getData​(DataKey<M> key)
      Gets data for this node using the given key.
      Type Parameters:
      M - The type of the data.
      Parameters:
      key - The key for the data
      Returns:
      The data.
      Throws:
      IllegalStateException - if the key was not set in this node.
      See Also:
      containsData(DataKey), DataKey

    • getDataKeys

      public Set<DataKey<?>> getDataKeys()
      This method was added to support the clone method.
      Returns:
      all known data keys.

    • setData

      public <M> void setData​(DataKey<M> key, M object)
      Sets data for this node 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

    • containsData

      public boolean containsData​(DataKey<?> key)
      Returns:
      does this node have data for this key?
      See Also:
      DataKey

    • removeData

      public void removeData​(DataKey<?> key)
      Remove data by key.
      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

    • replace

      public boolean replace​(Node node)
      Try to replace this node in the parent with the supplied node.
      Returns:
      true if removed, 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
      Returns the parent node from the perspective of the children of this node.

      That is, this method returns this for everything except NodeList. A NodeList returns its parent node instead. This is because a NodeList sets the parent of all its children to its own parent node (see NodeList for details).

      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

    • remove

      public boolean remove​(Node node)

    • removeComment

      public Node removeComment()

    • clone

      public Node clone()
      Overrides:
      clone in class Object

    • getMetaModel

      public NodeMetaModel getMetaModel()
      Returns:
      get JavaParser specific node introspection information.

    • getParsed

      public Node.Parsedness getParsed()
      Returns:
      whether this node was successfully parsed or not. If it was not, only the range and tokenRange fields will be valid.

    • setParsed

      public Node setParsed​(Node.Parsedness parsed)
      Used by the parser to flag unparsable nodes.

    • replace

      public boolean replace​(Node node, Node replacementNode)

    • findRootNode

      public Node findRootNode()
      Finds the root node of this AST by finding the topmost parent.

    • findCompilationUnit

      public Optional<CompilationUnit> findCompilationUnit()
      Returns:
      the containing CompilationUnit, or empty if this node is not inside a compilation unit.

    • getLineEndingStyleOrDefault

      public LineSeparator getLineEndingStyleOrDefault​(LineSeparator defaultLineSeparator)

    • getLineEndingStyle

      public LineSeparator getLineEndingStyle()

    • getSymbolResolver

      protected SymbolResolver getSymbolResolver()

    • stream

      public Stream<Node> stream​(Node.TreeTraversal traversal)
      Make a stream of nodes using traversal algorithm "traversal".

    • stream

      public Stream<Node> stream()
      Make a stream of nodes using pre-order traversal.

    • walk

      public void walk​(Node.TreeTraversal traversal, Consumer<Node> consumer)
      Walks the AST, calling the consumer for every node, with traversal algorithm "traversal".
      This is the most general walk method. All other walk and findAll methods are based on this.

    • walk

      public void walk​(Consumer<Node> consumer)
      Walks the AST, calling the consumer for every node with pre-order traversal.

    • walk

      public <T extends Node> void walk​(Class<T> nodeType, Consumer<T> consumer)
      Walks the AST with pre-order traversal, calling the consumer for every node of type "nodeType".

    • findAll

      public <T extends Node> List<T> findAll​(Class<T> nodeType)
      Walks the AST with pre-order traversal, returning all nodes of type "nodeType".

    • findAll

      public <T extends Node> List<T> findAll​(Class<T> nodeType, Node.TreeTraversal traversal)
      Walks the AST with specified traversal order, returning all nodes of type "nodeType".

    • findAll

      public <T extends Node> List<T> findAll​(Class<T> nodeType, Predicate<T> predicate)
      Walks the AST with pre-order traversal, returning all nodes of type "nodeType" that match the predicate.

    • findFirst

      public <T> Optional<T> findFirst​(Node.TreeTraversal traversal, Function<Node,​Optional<T>> consumer)
      Walks the AST, applying the function for every node, with traversal algorithm "traversal". If the function returns something else than null, the traversal is stopped and the function result is returned.
      This is the most general findFirst method. All other findFirst methods are based on this.

    • findFirst

      public <N extends Node> Optional<N> findFirst​(Class<N> nodeType)
      Walks the AST with pre-order traversal, returning the first node of type "nodeType" or empty() if none is found.

    • findFirst

      public <N extends Node> Optional<N> findFirst​(Class<N> nodeType, Predicate<N> predicate)
      Walks the AST with pre-order traversal, returning the first node of type "nodeType" that matches "predicate" or empty() if none is found.

    • isAncestorOf

      public boolean isAncestorOf​(Node descendant)
      Determines whether this node is an ancestor of the given node. A node is not an ancestor of itself.
      Parameters:
      descendant - the node for which to determine whether it has this node as an ancestor.
      Returns:
      true if this node is an ancestor of the given node, and false otherwise.
      See Also:
      HasParentNode.isDescendantOf(Node)

    • hasScope

      public boolean hasScope()

    • isPhantom

      public boolean isPhantom()