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Java library for cluster communications and computing.
There is a newer version: 4.1.3
/*
 * Copyright 2020 The Hekate Project
 *
 * The Hekate Project 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 io.hekate.partition;

import io.hekate.cluster.ClusterNode;
import io.hekate.cluster.ClusterNodeId;
import io.hekate.cluster.ClusterTopology;
import java.util.List;

/**
 * Data partition.
 *
 * 
 * This interface provides an information about a {@link #primaryNode() primary} node and its {@link #backupNodes() backup} nodes that were
 * selected by a {@link PartitionMapper partition mapper} based on its cluster topology view.
 * 
 *
 * 
 * Note that all instances of this interface must be immutable and must not change once obtained from a {@link PartitionMapper}.
 * 
 *
 * @see PartitionMapper#map(Object)
 */
public interface Partition extends Comparable {
    /**
     * Returns the partition identifier.
     *
     * @return Partition identifier.
     */
    int id();

    /**
     * Returns the primary node that is assigned to this partition.
     *
     * @return Primary node.
     */
    ClusterNode primaryNode();

    /**
     * Returns the backup node set of this partition.
     *
     * @return Set of backup nodes or an empty set if there are no backup nodes.
     */
    List backupNodes();

    /**
     * Returns the set of all nodes that are mapped to this partition (including {@link #primaryNode() primary} and {@link
     * #backupNodes() backup}).
     *
     * @return The set of all nodes that are mapped to this partition.
     */
    List nodes();

    /**
     * Returns the cluster topology that this partition is mapped to.
     *
     * @return Cluster topology that this partition is mapped to.
     */
    ClusterTopology topology();

    /**
     * Returns {@code true} if the specified node is primary for this partition (see {@link #primaryNode()}).
     *
     * @param node Node identifier.
     *
     * @return {@code true} if the specified node is primary for this partition (see {@link #primaryNode()}).
     */
    default boolean isPrimary(ClusterNodeId node) {
        ClusterNode primary = primaryNode();

        return primary != null && primary.id().equals(node);
    }

    /**
     * Returns {@code true} if the specified node is primary for this partition (see {@link #primaryNode()}).
     *
     * @param node Node.
     *
     * @return {@code true} if the specified node is primary for this partition (see {@link #primaryNode()}).
     */
    default boolean isPrimary(ClusterNode node) {
        ClusterNode primary = primaryNode();

        return primary != null && primary.equals(node);

    }

    /**
     * Returns {@code true} if this partition has {@link #backupNodes()}.
     *
     * @return {@code true} if this partition has {@link #backupNodes()}.
     */
    default boolean hasBackupNodes() {
        return !backupNodes().isEmpty();
    }

    /**
     * Compares this partition with the specified one based on {@link #id()}  value.
     *
     * @param o Other partition.
     *
     * @return Result of {@link #id()} values comparison.
     */
    @Override
    default int compareTo(Partition o) {
        return Integer.compare(id(), o.id());
    }
}