Package 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	Description
protected XPathElement[]	elements
static String	NOT
protected Parser	parser
protected String	path
static String	WILDCARD

Constructor Summary

Constructors

Constructor	Description
XPath(Parser parser, String path)

Method Summary

Modifier and Type	Method	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).