Package net.sourceforge.pmd.lang.ast

Interface Node

  • All Known Subinterfaces:
    DFAGraphMethod, QualifiableNode, RootNode, ScopedNode, SignedNode<N>
    All Known Implementing Classes:
    AbstractJjtreeNode, AbstractNode, PlainTextLanguage.PlainTextFile
    public interface Node
    Root interface for all AST nodes. This interface provides only the API shared by all AST implementations in PMD language modules. This includes for now: Additionally, the user data map is an extensibility mechanism with which any client can independently associate values to AST nodes.

    Every language implementation must publish a sub-interface of Node which serves as a supertype for all nodes of that language (e.g. pmd-java provides JavaNode, pmd-apex provides ApexNode, etc.). It is assumed in many places that the getChild(int) and getParent() method return an instance of this sub-interface. For example, no JSP node should have a Java node as its child. Embedding nodes from different languages will not be done via these methods, and conforming implementations should ensure that every node returned by these methods are indeed of the same type. Possibly, a type parameter will be added to the Node interface in 7.0.0 to enforce it at compile-time.

    A number of methods are deprecated and will be removed in 7.0.0. Most of them are implementation details that clutter this API and make implementation more difficult. Some methods prefixed with jjt have a more conventional counterpart (e.g. jjtGetParent() and getParent()) that should be preferred.

    • Method Detail

      • jjtOpen

        @Deprecated
void jjtOpen()
        Deprecated.
        This is JJTree-specific and will be removed from this interface
        This method is called after the node has been made the current node. It indicates that child nodes can now be added to it.

      • jjtClose

        @Deprecated
void jjtClose()
        Deprecated.
        This is JJTree-specific and will be removed from this interface
        This method is called after all the child nodes have been added.

      • jjtSetParent

        @Deprecated
void jjtSetParent​(Node parent)
        Deprecated.
        This is JJTree-specific and will be removed from this interface
        Sets the parent of this node.
        Parameters:
        parent - The parent

      • jjtGetParent

        @Deprecated
Node jjtGetParent()
        Deprecated.
        Use getParent()
        Returns the parent of this node.
        Returns:
        The parent of the node

      • jjtAddChild

        @Deprecated
void jjtAddChild​(Node child,
                 int index)
        Deprecated.
        This is JJTree-specific and will be removed from this interface
        This method tells the node to add its argument to the node's list of children.
        Parameters:
        child - The child to add
        index - The index to which the child will be added

      • jjtSetChildIndex

        @Deprecated
void jjtSetChildIndex​(int index)
        Deprecated.
        This is JJTree-specific and will be removed from this interface
        Sets the index of this node from the perspective of its parent. This means: this.getParent().getChild(index) == this.
        Parameters:
        index - the child index

      • jjtGetChildIndex

        @Deprecated
int jjtGetChildIndex()
        Deprecated.
        Use getIndexInParent()
        Gets the index of this node in the children of its parent.
        Returns:
        The index of the node

      • jjtGetChild

        @Deprecated
Node jjtGetChild​(int index)
        Deprecated.
        Use getChild(int)
        This method returns a child node. The children are numbered from zero, left to right.
        Parameters:
        index - the child index. Must be nonnegative and less than jjtGetNumChildren().

      • jjtGetId

        @Deprecated
int jjtGetId()
        Deprecated.
        This is JJTree-specific and will be removed from this interface.

      • getImage

        String getImage()
        Returns a string token, usually filled-in by the parser, which describes some textual characteristic of this node. This is usually an identifier, but you should check that using the Designer. On most nodes though, this method returns null.

      • setImage

        @InternalApi
@Deprecated
void setImage​(String image)
        Deprecated.
        This is internal API, the image should never be set by developers.

      • hasImageEqualTo

        boolean hasImageEqualTo​(String image)
        Returns true if this node's image is equal to the given string.
        Parameters:
        image - The image to check

      • getBeginLine

        int getBeginLine()

      • getBeginColumn

        int getBeginColumn()

      • getEndLine

        int getEndLine()

      • getEndColumn

        int getEndColumn()

      • getDataFlowNode

        @Deprecated
DataFlowNode getDataFlowNode()
        Deprecated.
        This is Java-specific and will be removed from this interface

      • setDataFlowNode

        @Deprecated
void setDataFlowNode​(DataFlowNode dataFlowNode)
        Deprecated.
        This is Java-specific and will be removed from this interface

      • isFindBoundary

        @DeprecatedAttribute
boolean isFindBoundary()
        Returns true if this node is considered a boundary by traversal methods. Traversal methods such as getFirstDescendantOfType(Class) don't look past such boundaries by default, which is usually the expected thing to do. For example, in Java, lambdas and nested classes are considered find boundaries.

        Note: This attribute is deprecated for XPath queries. It is not useful for XPath queries and will be removed with PMD 7.0.0.

      • getNthParent

        Node getNthParent​(int n)
        Returns the n-th parent or null if there are less than n ancestors.
        Parameters:
        n - how many ancestors to iterate over.
        Returns:
        the n-th parent or null.
        Throws:
        IllegalArgumentException - if n is negative or zero.

      • getFirstParentOfType

        <T> T getFirstParentOfType​(Class<T> parentType)
        Traverses up the tree to find the first parent instance of type parentType or one of its subclasses.
        Type Parameters:
        T - The type you want to find
        Parameters:
        parentType - Class literal of the type you want to find
        Returns:
        Node of type parentType. Returns null if none found.

      • getParentsOfType

        <T> List<T> getParentsOfType​(Class<T> parentType)
        Traverses up the tree to find all of the parent instances of type parentType or one of its subclasses. The nodes are ordered deepest-first.
        Type Parameters:
        T - The type you want to find
        Parameters:
        parentType - Class literal of the type you want to find
        Returns:
        List of parentType instances found.

      • getFirstParentOfAnyType

        @Deprecated
<T> T getFirstParentOfAnyType​(Class<? extends T>... parentTypes)
        Deprecated.
        This method causes an unchecked warning at call sites. PMD 7 will provide a way to do the same thing without the warning.
        Gets the first parent that's an instance of any of the given types.
        Type Parameters:
        T - Most specific common type of the parameters
        Parameters:
        parentTypes - Types to look for
        Returns:
        The first parent with a matching type. Returns null if there is no such parent

      • findChildrenOfType

        <T> List<T> findChildrenOfType​(Class<T> childType)
        Traverses the children to find all the instances of type childType or one of its subclasses.
        Parameters:
        childType - class which you want to find.
        Returns:
        List of all children of type childType. Returns an empty list if none found.
        See Also:
        if traversal of the entire tree is needed.

      • findDescendantsOfType

        <T> List<T> findDescendantsOfType​(Class<? extends T> targetType)
        Traverses down the tree to find all the descendant instances of type descendantType without crossing find boundaries.
        Parameters:
        targetType - class which you want to find.
        Returns:
        List of all children of type targetType. Returns an empty list if none found.

      • findDescendantsOfType

        @Deprecated
<T> void findDescendantsOfType​(Class<T> targetType,
                               List<T> results,
                               boolean crossFindBoundaries)
        Deprecated.
        Use findDescendantsOfType(Class, boolean) instead, which returns a result list.
        Traverses down the tree to find all the descendant instances of type descendantType.
        Parameters:
        targetType - class which you want to find.
        results - list to store the matching descendants
        crossFindBoundaries - if false, recursion stops for nodes for which isFindBoundary() is true

      • findDescendantsOfType

        <T> List<T> findDescendantsOfType​(Class<T> targetType,
                                  boolean crossFindBoundaries)
        Traverses down the tree to find all the descendant instances of type descendantType.
        Parameters:
        targetType - class which you want to find.
        crossFindBoundaries - if false, recursion stops for nodes for which isFindBoundary() is true
        Returns:
        List of all matching descendants

      • getFirstChildOfType

        <T> T getFirstChildOfType​(Class<T> childType)
        Traverses the children to find the first instance of type childType.
        Parameters:
        childType - class which you want to find.
        Returns:
        Node of type childType. Returns null if none found.
        See Also:
        if traversal of the entire tree is needed.

      • getFirstDescendantOfType

        <T> T getFirstDescendantOfType​(Class<T> descendantType)
        Traverses down the tree to find the first descendant instance of type descendantType without crossing find boundaries.
        Parameters:
        descendantType - class which you want to find.
        Returns:
        Node of type descendantType. Returns null if none found.

      • hasDescendantOfType

        <T> boolean hasDescendantOfType​(Class<T> type)
        Finds if this node contains a descendant of the given type without crossing find boundaries.
        Parameters:
        type - the node type to search
        Returns:
        true if there is at least one descendant of the given type

      • findChildNodesWithXPath

        @Deprecated
List<? extends Node> findChildNodesWithXPath​(String xpathString)
                                      throws org.jaxen.JaxenException
        Deprecated.
        This is very inefficient and should not be used in new code. PMD 7.0.0 will remove support for this method.
        Returns all the nodes matching the xpath expression.
        Parameters:
        xpathString - the expression to check
        Returns:
        List of all matching nodes. Returns an empty list if none found.
        Throws:
        org.jaxen.JaxenException - if the xpath is incorrect or fails altogether

      • hasDescendantMatchingXPath

        @Deprecated
boolean hasDescendantMatchingXPath​(String xpathString)
        Deprecated.
        This is very inefficient and should not be used in new code. PMD 7.0.0 will remove support for this method.
        Checks whether at least one descendant matches the xpath expression.
        Parameters:
        xpathString - the expression to check
        Returns:
        true if there is a match

      • getAsDocument

        @Deprecated
Document getAsDocument()
        Deprecated.
        Converting a tree to a DOM is not a standard use case. The implementation rethrows a ParserConfigurationException as a RuntimeException, but a caller should handle it if he really wants to do this. Another problem is that this is available on any node, yet only the root node of a tree corresponds really to a document. The conversion is easy to implement anyway, and does not have to be part of this API.
        Get a DOM Document which contains Elements and Attributes representative of this Node and it's children. Essentially a DOM tree representation of the Node AST, thereby allowing tools which can operate upon DOM to also indirectly operate on the AST.

      • setUserData

        @Deprecated
void setUserData​(Object userData)
        Deprecated.
        Use getUserMap()
        Set the user data associated with this node.

        PMD itself will never set user data onto a node. Nor should any Rule implementation, as the AST nodes are shared between concurrently executing Rules (i.e. it is not thread-safe).

        This API is most useful for external applications looking to leverage PMD's robust support for AST structures, in which case application specific annotations on the AST nodes can be quite useful.

        Parameters:
        userData - The data to set on this node.

      • remove

        @Deprecated
@InternalApi
void remove()
        Deprecated.
        This is internal API and will be removed from this interface with 7.0.0
        Remove the current node from its parent.

      • removeChildAtIndex

        @Deprecated
@InternalApi
void removeChildAtIndex​(int childIndex)
        Deprecated.
        This is internal API and will be removed from this interface with 7.0.0
        This method tells the node to remove the child node at the given index from the node's list of children, if any; if not, no changes are done.
        Parameters:
        childIndex - The index of the child to be removed

      • getParent

        Node getParent()
        Returns the parent of this node, or null if this is the root of the tree.

        This method should be preferred to jjtGetParent().

        Returns:
        The parent of this node

      • getNumChildren

        int getNumChildren()
        Returns the number of children of this node.

      • getIndexInParent

        int getIndexInParent()
        Returns the index of this node in its parent's children. If this node is a root node, returns -1.

        This method replaces jjtGetChildIndex(), whose name was JJTree-specific.

        Returns:
        The index of this node in its parent's children

      • getXPathNodeName

        String getXPathNodeName()
        Gets the name of the node that is used to match it with XPath queries.
        Returns:
        The XPath node name

      • getXPathAttributesIterator

        Iterator<Attribute> getXPathAttributesIterator()
        Returns an iterator enumerating all the attributes that are available from XPath for this node.
        Returns:
        An attribute iterator for this node

      • children

        Iterable<? extends Node> children()
        Returns an iterable enumerating the children of this node. Use it with a foreach loop: 
        
      for (Node child : node.children()) {
          // process child
      }

        This method's return type will be changed to NodeStream in PMD 7, which is a more powerful kind of iterable. The change will be source compatible.

        Returns:
        A new iterable for the children of this node