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/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.runtime.tree.pattern;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.xpath.XPath;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
/**
* A pattern like {@code = ;} converted to a {@link ParseTree} by
* {@link ParseTreePatternMatcher#compile(String, int)}.
*/
public class ParseTreePattern {
/**
* This is the backing field for {@link #getPatternRuleIndex()}.
*/
private final int patternRuleIndex;
/**
* This is the backing field for {@link #getPattern()}.
*/
private final String pattern;
/**
* This is the backing field for {@link #getPatternTree()}.
*/
private final ParseTree patternTree;
/**
* This is the backing field for {@link #getMatcher()}.
*/
private final ParseTreePatternMatcher matcher;
/**
* Construct a new instance of the {@link ParseTreePattern} class.
*
* @param matcher The {@link ParseTreePatternMatcher} which created this
* tree pattern.
* @param pattern The tree pattern in concrete syntax form.
* @param patternRuleIndex The parser rule which serves as the root of the
* tree pattern.
* @param patternTree The tree pattern in {@link ParseTree} form.
*/
public ParseTreePattern(ParseTreePatternMatcher matcher,
String pattern, int patternRuleIndex, ParseTree patternTree)
{
this.matcher = matcher;
this.patternRuleIndex = patternRuleIndex;
this.pattern = pattern;
this.patternTree = patternTree;
}
/**
* Match a specific parse tree against this tree pattern.
*
* @param tree The parse tree to match against this tree pattern.
* @return A {@link ParseTreeMatch} object describing the result of the
* match operation. The {@link ParseTreeMatch#succeeded()} method can be
* used to determine whether or not the match was successful.
*/
public ParseTreeMatch match(ParseTree tree) {
return matcher.match(tree, this);
}
/**
* Determine whether or not a parse tree matches this tree pattern.
*
* @param tree The parse tree to match against this tree pattern.
* @return {@code true} if {@code tree} is a match for the current tree
* pattern; otherwise, {@code false}.
*/
public boolean matches(ParseTree tree) {
return matcher.match(tree, this).succeeded();
}
/**
* Find all nodes using XPath and then try to match those subtrees against
* this tree pattern.
*
* @param tree The {@link ParseTree} to match against this pattern.
* @param xpath An expression matching the nodes
*
* @return A collection of {@link ParseTreeMatch} objects describing the
* successful matches. Unsuccessful matches are omitted from the result,
* regardless of the reason for the failure.
*/
public List findAll(ParseTree tree, String xpath) {
Collection subtrees = XPath.findAll(tree, xpath, matcher.getParser());
List matches = new ArrayList();
for (ParseTree t : subtrees) {
ParseTreeMatch match = match(t);
if ( match.succeeded() ) {
matches.add(match);
}
}
return matches;
}
/**
* Get the {@link ParseTreePatternMatcher} which created this tree pattern.
*
* @return The {@link ParseTreePatternMatcher} which created this tree
* pattern.
*/
public ParseTreePatternMatcher getMatcher() {
return matcher;
}
/**
* Get the tree pattern in concrete syntax form.
*
* @return The tree pattern in concrete syntax form.
*/
public String getPattern() {
return pattern;
}
/**
* Get the parser rule which serves as the outermost rule for the tree
* pattern.
*
* @return The parser rule which serves as the outermost rule for the tree
* pattern.
*/
public int getPatternRuleIndex() {
return patternRuleIndex;
}
/**
* Get the tree pattern as a {@link ParseTree}. The rule and token tags from
* the pattern are present in the parse tree as terminal nodes with a symbol
* of type {@link RuleTagToken} or {@link TokenTagToken}.
*
* @return The tree pattern as a {@link ParseTree}.
*/
public ParseTree getPatternTree() {
return patternTree;
}
}