Stream vs iterator

gistfile1.txt

/*
 * Copyright 2017 LINE Corporation
 *
 * LINE Corporation 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 com.linecorp.armeria.server.http.dynamic;

import java.util.List;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.infra.Blackhole;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Streams;

public class StreamVsIteratorBenchmark {

    private static final List<String> REQUIRED = ImmutableList.of("foo", "bar", "cat", "dog");
    private static final List<String> ACTUAL = ImmutableList.of("foo", "bar", "cat", "dog");

    @Benchmark
    public void testIterator(Blackhole bh) {
        bh.consume(containsAllRequiredValues(REQUIRED, ACTUAL));
    }

    @Benchmark
    public void testStream(Blackhole bh) {
        bh.consume(containsAllRequiredValuesStream(REQUIRED, ACTUAL));
    }

    private static boolean containsAllRequiredValuesStream(
            Iterable<String> requiredValues, Iterable<String> actualValues) {
        return Streams.stream(requiredValues).allMatch(s -> containsRequiredValueStream(s, actualValues));
    }

    private static boolean containsRequiredValueStream(String requiredValue, Iterable<String> actualValues) {
        return Streams.stream(actualValues).anyMatch(requiredValue::equalsIgnoreCase);
    }

    private static boolean containsAllRequiredValues(Iterable<String> requiredValues,
                                                     Iterable<String> actualValues) {
        for (String requiredValue : requiredValues) {
            if (!containsRequiredValue(requiredValue, actualValues)) {
                return false;
            }
        }
        return true;
    }

    private static boolean containsRequiredValue(String requiredValue, Iterable<String> actualValues) {
        for (String actualValue : actualValues) {
            if (requiredValue.equalsIgnoreCase(actualValue)) {
                return true;
            }
        }
        return false;
    }
}