public Class XPath

Class Inheritance

extends Object

java.lang.Object
org.antlr.v4.runtime.tree.xpath.XPath

Imports

org.antlr.v4.runtime.ANTLRInputStream, .CommonTokenStream, .LexerNoViableAltException, .Parser, .ParserRuleContext, .Token, org.antlr.v4.runtime.tree.ParseTree, java.io.IOException, .StringReader, java.util.ArrayList, .Collection, .Collections, .LinkedHashSet, .List

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

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

Constructor Summary

Access	Constructor and Description
public	XPath(Parser parser, String path)

Method Summary

Modifier and Type	Method and Description
public Collection<ParseTree>	evaluate(final ParseTree t) Return a list of all nodes starting at `t` as root that satisfy the path.
public 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.
public XPathElement[]	split(String path)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

elements	back to summary
protected XPathElement[] elements

NOT	back to summary
public static final String NOT

parser	back to summary
protected Parser parser

path	back to summary
protected String path

WILDCARD	back to summary
public static final String WILDCARD

Constructor Detail

XPath	back to summary
public XPath(Parser parser, String path)

Method Detail

evaluate	back to summary
public Collection<ParseTree> evaluate(final 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`.

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

getXPathElement	back to summary
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.

split	back to summary
public XPathElement[] split(String path)