eagle-core/eagle-query/eagle-antlr/src/main/java/org/apache/eagle/query/parser/EagleQueryParser.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.eagle.query.parser;

import org.apache.eagle.query.antlr.generated.EagleFilterLexer;
import org.apache.eagle.query.antlr.generated.EagleFilterParser;
import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class EagleQueryParser {
    private static final Logger LOG = LoggerFactory.getLogger(EagleQueryParser.class);
    private String query;

    public EagleQueryParser(String query) {
        this.query = query;
    }

    public ORExpression parse() throws EagleQueryParseException {
        try {
            EagleFilterLexer lexer = new EagleFilterLexer(new ANTLRInputStream(query));
            CommonTokenStream tokens = new CommonTokenStream(lexer);
            tokens.fill();
            EagleFilterParser p = new EagleFilterParser(tokens);
            p.setErrorHandler(new EagleANTLRErrorStrategy());
            p.setBuildParseTree(true);
            EagleQueryFilterListenerImpl listener = new EagleQueryFilterListenerImpl();
            p.addParseListener(listener);
            EagleFilterParser.FilterContext fc = p.filter();
            if (fc.exception != null) {
                LOG.error("Can not successfully parse the query:" + query, fc.exception);
                throw fc.exception;
            }
            return listener.result();
        } catch (Exception ex) {
            LOG.error("Can not successfully parse the query:", ex);
            throw new EagleQueryParseException("can not successfully parse the query:" + query);
        }
    }
}