eagle-core/eagle-query/eagle-query-base/src/main/java/org/apache/eagle/query/aggregate/SortFieldOrderType.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.aggregate;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public enum SortFieldOrderType {
    key("^(key)=(asc|desc)$"),
    count("^(count)=(asc|desc)$"),
    sum("^sum\\((.*)\\)=(asc|desc)$"),
    avg("^avg\\((.*)\\)(asc|desc)$"),
    max("^max\\((.*)\\)(asc|desc)$"),
    min("^min\\((.*)\\)(asc|desc)$");

    private Pattern pattern;
    private SortFieldOrderType(String patternString) {
        this.pattern = Pattern.compile(patternString);
    }

    /**
     * This method is thread safe
     * match and retrieve back the aggregated fields, for count, aggregateFields can be null
     * @param sortFieldOrder
     * @return
     */
    public SortFieldOrderTypeMatcher matcher(String sortFieldOrder) {
        Matcher m = pattern.matcher(sortFieldOrder);

        if (m.find()) {
            return new SortFieldOrderTypeMatcher(true, m.group(1), m.group(2));
        } else {
            return new SortFieldOrderTypeMatcher(false, null, null);
        }
    }

    public static AggregateParams.SortFieldOrder matchAll(String sortFieldOrder) {
        for (SortFieldOrderType type : SortFieldOrderType.values()) {
            SortFieldOrderTypeMatcher m = type.matcher(sortFieldOrder);
            if (m.isMatched()) {
                return m.sortFieldOrder();
            }
        }
        return null;
    }
}