EvalTermEmitterFactory.java

package org.araqne.logdb.query.parser;

import java.util.Stack;

import org.araqne.logdb.query.expr.BooleanConstant;
import org.araqne.logdb.query.expr.EvalField;
import org.araqne.logdb.query.expr.Expression;
import org.araqne.logdb.query.expr.NullConstant;
import org.araqne.logdb.query.expr.NumberConstant;
import org.araqne.logdb.query.expr.StringConstant;
import org.araqne.logdb.query.parser.ExpressionParser.TokenTerm;

public class EvalTermEmitterFactory implements TermEmitterFactory {
	@Override
	public void emit(Stack<Expression> exprStack, TokenTerm t) {
		if (!t.getText().equals("(") && !t.getText().equals(")")) {
			String token = ((TokenTerm) t).getText().trim();
			Expression expr = parseTokenExpr(exprStack, token);
			exprStack.add(expr);
		}
	}

	private Expression parseTokenExpr(Stack<Expression> exprStack, String token) {
		// is quoted?
		if (token.startsWith("\"") && token.endsWith("\""))
			return new StringConstant(token.substring(1, token.length() - 1));

		if (token.equals("true") || token.equals("false"))
			return new BooleanConstant(Boolean.parseBoolean(token));
		
		if (token.equals("null"))
			return new NullConstant();

		try {
			long v = Long.parseLong(token);
			if (Integer.MIN_VALUE <= v && v <= Integer.MAX_VALUE)
				return new NumberConstant((int) v);
			return new NumberConstant(v);
		} catch (NumberFormatException e1) {
			try {
				double v = Double.parseDouble(token);
				return new NumberConstant(v);
			} catch (NumberFormatException e2) {

				return new EvalField(token);
			}
		}
	}
}