net.sf.xmlform.expression.ExpressionParser Maven / Gradle / Ivy

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package net.sf.xmlform.expression;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import net.sf.xmlform.expression.impl.formExpressionLexer;
import net.sf.xmlform.expression.impl.formExpressionParser;

import org.antlr.v4.runtime.BaseErrorListener;
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CodePointCharStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.RecognitionException;
import org.antlr.v4.runtime.Recognizer;

/**
 * @author Liu Zhikun
 */

public class ExpressionParser {
	static public Factor parse(String expression) throws Exception{
		if(expression==null||expression.length()==0){
			Str str=new Str();
			str.setString("\"\"");
			return str;
		}
		StringBuilder errorSb=new StringBuilder();
		BaseErrorListener errorListener=new InnerErrorListener(errorSb);
		CodePointCharStream input = CharStreams.fromString(expression);
		formExpressionLexer lexer = new formExpressionLexer(input);
		lexer.removeErrorListeners();
		lexer.addErrorListener(errorListener);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        formExpressionParser parser = new formExpressionParser(tokens);
        parser.setBuildParseTree(false);
        parser.removeErrorListeners();
        parser.addErrorListener(errorListener);
        try {
        	Factor factor=parser.program().factor;
        	if(errorSb.length()>0) {
        		throw new ExpressionException("Expression ["+expression+"] "+errorSb.toString()+". ");
        	}
            return factor;
        } catch (RecognitionException e) {
            throw new ExpressionException(e.getLocalizedMessage(),e);
        }
	}
	static public Set getDependFields(Factor factor){
		Set box=new HashSet();
		getDepends(factor,box);
		return box;
	}
	static private void getDepends(Factor factor,Set box){
		if(factor instanceof Field)
			box.add(((Field)factor).getName());
		else if(factor instanceof Function)
			getDependsFromFun((Function)factor,box);
	}
	static private void getDependsFromFun(Function fun,Set box){
		List args=fun.getArguments();
		int size=args.size();
		for(int i=0;i recognizer, Object offendingSymbol, int line,
				int charPositionInLine, String msg, RecognitionException e) {
			if(errorSb.length()>0)
				errorSb.append("; ");
			errorSb.append("line: "+line+", pos: "+charPositionInLine+": "+msg);
		}
		
	};
}