/*
 * Copyright 2016-present Open Networking Laboratory
 *
 * Licensed 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.onosproject.store.service;

import com.google.common.base.MoreObjects;

/**
 * Statistics for a {@link WorkQueue}.
 */
public final class WorkQueueStats {

    private long totalPending;
    private long totalInProgress;
    private long totalCompleted;

    /**
     * Returns a {@code WorkQueueStats} builder.
     * @return builder
     */
    public static Builder builder() {
        return new Builder();
    }

    private WorkQueueStats() {
    }

    public static class Builder {

        WorkQueueStats workQueueStats = new WorkQueueStats();

        public Builder withTotalPending(long value) {
            workQueueStats.totalPending = value;
            return this;
        }

        public Builder withTotalInProgress(long value) {
            workQueueStats.totalInProgress = value;
            return this;
        }

        public Builder withTotalCompleted(long value) {
            workQueueStats.totalCompleted = value;
            return this;
        }

        public WorkQueueStats build() {
            return workQueueStats;
        }
    }

    /**
     * Returns the total pending tasks. These are the tasks that are added but not yet picked up.
     * @return total pending tasks.
     */
    public long totalPending() {
        return this.totalPending;
    }

    /**
     * Returns the total in progress tasks. These are the tasks that are currently being worked on.
     * @return total in progress tasks.
     */
    public long totalInProgress() {
        return this.totalInProgress;
    }

    /**
     * Returns the total completed tasks.
     * @return total completed tasks.
     */
    public long totalCompleted() {
        return this.totalCompleted;
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(getClass())
                .add("totalPending", totalPending)
                .add("totalInProgress", totalInProgress)
                .add("totalCompleted", totalCompleted)
                .toString();
    }
}