org.antlr.v4.runtime.tree.xpath

Class XPath

java.lang.Object

org.antlr.v4.runtime.tree.xpath.XPath

public class XPath
extends Object

Represent a subset of XPath XML path syntax for use in identifying nodes in parse trees.

Split path into words and separators / and // via ANTLR itself then walk path elements from left to right. At each separator-word pair, find set of nodes. Next stage uses those as work list.

The basic interface is ParseTree.findAll(tree, pathString, parser). But that is just shorthand for:

 XPath p = new XPath(parser, pathString);
 return p.evaluate(tree);
 

See org.antlr.v4.test.TestXPath for descriptions. In short, this allows operators:

/

root

//

anywhere

!

invert; this must appear directly after root or anywhere operator

and path elements:

ID

token name

'string'

any string literal token from the grammar

expr

rule name

*

wildcard matching any node

Whitespace is not allowed.

Field Summary

Fields

Modifier and Type	Field and Description
protected XPathElement[]	elements
static String	NOT
protected Parser	parser
protected String	path
static String	WILDCARD

Constructor Summary

Constructors

Constructor and Description
XPath(Parser parser, String path)

Method Summary

Methods

Modifier and Type	Method and Description
Collection<ParseTree>	evaluate(ParseTree t) Return a list of all nodes starting at t as root that satisfy the path.
static Collection<ParseTree>	findAll(ParseTree tree, String xpath, Parser parser)
protected XPathElement	getXPathElement(Token wordToken, boolean anywhere) Convert word like * or ID or expr to a path element.
XPathElement[]	split(String path)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

WILDCARD

public static final String WILDCARD

See Also:

Constant Field Values

NOT

public static final String NOT

See Also:

Constant Field Values

path

protected String path

elements

protected XPathElement[] elements

parser

protected Parser parser

Constructor Detail

XPath

public XPath(Parser parser,
     String path)

Method Detail

split

public XPathElement[] split(String path)

getXPathElement

protected XPathElement getXPathElement(Token wordToken,
                           boolean anywhere)

Convert word like * or ID or expr to a path element. anywhere is true if // precedes the word.

findAll

public static Collection<ParseTree> findAll(ParseTree tree,
                            String xpath,
                            Parser parser)

evaluate

public Collection<ParseTree> evaluate(ParseTree t)

Return a list of all nodes starting at t as root that satisfy the path. The root / is relative to the node passed to evaluate(org.antlr.v4.runtime.tree.ParseTree).