org.apache.james.queue.rabbitmq.view.cassandra.configuration.CassandraMailQueueViewConfiguration.java Source code

Introduction

Here is the source code for org.apache.james.queue.rabbitmq.view.cassandra.configuration.CassandraMailQueueViewConfiguration.java

Source

/****************************************************************
 * 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.james.queue.rabbitmq.view.cassandra.configuration;

import java.time.Duration;
import java.util.Objects;
import java.util.Optional;

import org.apache.commons.configuration.Configuration;
import org.apache.james.util.TimeConverter;

import com.google.common.base.MoreObjects;
import com.google.common.base.Preconditions;

public class CassandraMailQueueViewConfiguration {

    interface Builder {
        @FunctionalInterface
        interface RequireBucketCount {
            RequireUpdateBrowseStartPace bucketCount(int bucketCount);
        }

        @FunctionalInterface
        interface RequireUpdateBrowseStartPace {
            RequireSliceWindow updateBrowseStartPace(int updateBrowseStartPace);
        }

        @FunctionalInterface
        interface RequireSliceWindow {
            ReadyToBuild sliceWindow(Duration sliceWindow);
        }

        class ReadyToBuild {
            private final int bucketCount;
            private final int updateBrowseStartPace;
            private final Duration sliceWindow;

            private ReadyToBuild(int bucketCount, int updateBrowseStartPace, Duration sliceWindow) {
                this.bucketCount = bucketCount;
                this.updateBrowseStartPace = updateBrowseStartPace;
                this.sliceWindow = sliceWindow;
            }

            public CassandraMailQueueViewConfiguration build() {
                Preconditions.checkNotNull(sliceWindow, "'sliceWindow' is compulsory");
                Preconditions.checkState(bucketCount > 0, "'bucketCount' needs to be a strictly positive integer");
                Preconditions.checkState(updateBrowseStartPace > 0,
                        "'updateBrowseStartPace' needs to be a strictly positive integer");

                return new CassandraMailQueueViewConfiguration(bucketCount, updateBrowseStartPace, sliceWindow);
            }
        }
    }

    public static Builder.RequireBucketCount builder() {
        return bucketCount -> updateBrowseStartPace -> sliceWindow -> new Builder.ReadyToBuild(bucketCount,
                updateBrowseStartPace, sliceWindow);
    }

    private static final int DEFAULT_BUCKET_COUNT = 1;
    private static final Duration DEFAULT_SLICE_WINDOW = Duration.ofHours(1);
    private static final int DEFAULT_UPDATE_BROWSE_START_PACE = 1000;

    public static final CassandraMailQueueViewConfiguration DEFAULT = builder().bucketCount(DEFAULT_BUCKET_COUNT)
            .updateBrowseStartPace(DEFAULT_UPDATE_BROWSE_START_PACE).sliceWindow(DEFAULT_SLICE_WINDOW).build();

    public static final String BUCKET_COUNT_PROPERTY = "mailqueue.view.bucketCount";
    public static final String UPDATE_BROWSE_START_PACE_PROPERTY = "mailqueue.view.updateBrowseStartPace";
    public static final String SLICE_WINDOW_PROPERTY = "mailqueue.view.sliceWindow";

    public static CassandraMailQueueViewConfiguration from(Configuration configuration) {
        int bucketCount = configuration.getInteger(BUCKET_COUNT_PROPERTY, DEFAULT_BUCKET_COUNT);
        int updateBrowseStartPace = configuration.getInteger(UPDATE_BROWSE_START_PACE_PROPERTY,
                DEFAULT_UPDATE_BROWSE_START_PACE);
        Optional<String> sliceWindowAsString = Optional
                .ofNullable(configuration.getString(SLICE_WINDOW_PROPERTY, null));

        return builder().bucketCount(bucketCount).updateBrowseStartPace(updateBrowseStartPace)
                .sliceWindow(sliceWindowAsString.map(TimeConverter::getMilliSeconds).map(Duration::ofMillis)
                        .orElse(DEFAULT_SLICE_WINDOW))
                .build();
    }

    private final int bucketCount;
    private final int updateBrowseStartPace;
    private final Duration sliceWindow;

    private CassandraMailQueueViewConfiguration(int bucketCount, int updateBrowseStartPace, Duration sliceWindow) {
        this.bucketCount = bucketCount;
        this.updateBrowseStartPace = updateBrowseStartPace;
        this.sliceWindow = sliceWindow;
    }

    public int getUpdateBrowseStartPace() {
        return updateBrowseStartPace;
    }

    public int getBucketCount() {
        return bucketCount;
    }

    public Duration getSliceWindow() {
        return sliceWindow;
    }

    void validateConfigurationChange(CassandraMailQueueViewConfiguration configurationUpdate) {
        validateConfigurationChangeForSlice(configurationUpdate);
        validateConfigurationChangeForBuckets(configurationUpdate);
    }

    private void validateConfigurationChangeForSlice(CassandraMailQueueViewConfiguration configurationUpdate) {
        long updateSliceWindowInSecond = configurationUpdate.getSliceWindow().getSeconds();
        long currentSliceWindowInSecond = getSliceWindow().getSeconds();
        Preconditions.checkArgument(
                configurationUpdate.getSliceWindow().compareTo(getSliceWindow()) <= 0
                        && currentSliceWindowInSecond % updateSliceWindowInSecond == 0,
                "update 'sliceWindow'(" + configurationUpdate.getSliceWindow()
                        + ") have to be less than and divide the previous sliceWindow: " + getSliceWindow());
    }

    private void validateConfigurationChangeForBuckets(CassandraMailQueueViewConfiguration configurationUpdate) {
        Preconditions.checkArgument(configurationUpdate.getBucketCount() >= getBucketCount(),
                "can not set 'bucketCount'(" + configurationUpdate.getBucketCount()
                        + ") to be less than the current one: " + getBucketCount());
    }

    @Override
    public final boolean equals(Object o) {
        if (o instanceof CassandraMailQueueViewConfiguration) {
            CassandraMailQueueViewConfiguration that = (CassandraMailQueueViewConfiguration) o;

            return Objects.equals(this.bucketCount, that.bucketCount)
                    && Objects.equals(this.updateBrowseStartPace, that.updateBrowseStartPace)
                    && Objects.equals(this.sliceWindow, that.sliceWindow);
        }
        return false;
    }

    @Override
    public final int hashCode() {
        return Objects.hash(bucketCount, updateBrowseStartPace, sliceWindow);
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(this).add("bucketCount", bucketCount)
                .add("updateBrowseStartPace", updateBrowseStartPace).add("sliceWindow", sliceWindow).toString();
    }
}