metron-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From justinleet <...@git.apache.org>
Subject [GitHub] metron pull request #823: METRON-1286 Add MIN & MAX Stellar functions
Date Wed, 29 Nov 2017 21:25:32 GMT
Github user justinleet commented on a diff in the pull request:

    https://github.com/apache/metron/pull/823#discussion_r153919356
  
    --- Diff: metron-stellar/stellar-common/src/main/java/org/apache/metron/stellar/dsl/functions/OrdinalFunctions.java
---
    @@ -0,0 +1,93 @@
    +/**
    + * 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.metron.stellar.dsl.functions;
    +
    +import org.apache.metron.stellar.dsl.BaseStellarFunction;
    +import org.apache.metron.stellar.dsl.Stellar;
    +
    +import java.util.Collections;
    +import java.util.List;
    +import java.util.stream.Collectors;
    +
    +public class OrdinalFunctions {
    +
    +    /**
    +     * Stellar Function: MAX
    +     * <p>
    +     * Return the maximum value of a list of input values in a Stellar list
    +     */
    +    @Stellar(name = "MAX"
    +            , description = "Returns the maximum value of a list of input values"
    +            , params = {"list_of_values - Stellar list of values to evaluate. The list
may only contain 1 type of object (only strings or only numbers)" +
    +                        " and the objects must be comparable / ordinal"}
    +            , returns = "The highest value in the list, null if the list is empty or
the input values could not be ordered")
    +    public static class Max extends BaseStellarFunction {
    +
    +        @Override
    +        public Object apply(List<Object> args) {
    +            if (args.size() < 1 || args.get(0) == null) {
    +                throw new IllegalStateException("MAX function requires at least a Stellar
list of values");
    +            }
    +            List list = (List<Object>) args.get(0);
    +            return orderList(list, true);
    +        }
    +    }
    +
    +    /**
    +     * Stellar Function: MIN
    +     * <p>
    +     * Return the minimum value of a list of input values in a Stellar list
    +     */
    +    @Stellar(name = "MIN"
    +            , description = "Returns the minimum value of a list of input values"
    +            , params = {"list_of_values - Stellar list of values to evaluate. The list
may only contain 1 type of object (only strings or only numbers)" +
    +            " and the objects must be comparable / ordinal"}
    +            , returns = "The lowest value in the list, null if the list is empty or the
input values could not be ordered")
    +    public static class Min extends BaseStellarFunction {
    +        @Override
    +        public Object apply(List<Object> args) {
    +            if (args.size() < 1 || args.get(0) == null) {
    +                throw new IllegalStateException("MIN function requires at least a Stellar
list of values");
    +            }
    +            List list = (List<Object>) args.get(0);
    +            return orderList(list, false);
    +        }
    +    }
    +
    +    private static Object orderList(List<Object> list, Boolean max) {
    +        if (list.isEmpty()) {
    +            return null;
    +        }
    +        List filteredList = (List<Object>) list.stream().filter(index -> !(index
== null)).collect(Collectors.toList());
    +        if (filteredList.isEmpty()) {
    +            return null;
    +        }
    +        try {
    +            if (max) {
    +                Collections.sort(filteredList,Collections.reverseOrder());
    --- End diff --
    
    Well, that is disappointing, but makes sense.


---

Mime
View raw message