modules/core/src/main/java/org/apache/ignite/internal/GridClosureCallMode.java

/*
 * 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.ignite.internal;

import org.jetbrains.annotations.Nullable;

/**
 * Distribution modes for one or more closures executed via {@code Grid.call(...)} methods.
 * In other words, given a set of jobs (closures) and set of grid nodes this enumeration provides
 * three simple modes of how these jobs will be mapped to the nodes.
 * <p>
 * <b>Note</b> that if you need to provide custom distribution logic you need to
 * implement {@link org.apache.ignite.compute.ComputeTask} interface that allows you to customize every aspect of a
 * distributed Java code execution such as  mapping, load balancing, failover, collision
 * resolution, continuations, etc.
 */
public enum GridClosureCallMode {
    /**
     * In this mode all closures will be executed on each node.
     * This mode essentially allows to <tt>broadcast</tt> executions to all nodes.
     */
    BROADCAST,

    /**
     * In this mode closures will be executed on the nodes provided by the default
     * load balancer.
     * <p>
     * NOTE: this mode <b>must</b> be used for all cache affinity routing. Load balance
     * manager has specific logic to handle co-location between compute grid jobs and
     * in-memory data grid data. All other modes will not work for affinity-based co-location.
     */
    BALANCE;

    /** Enumerated values. */
    private static final GridClosureCallMode[] VALS = values();

    /**
     * Efficiently gets enumerated value from its ordinal.
     *
     * @param ord Ordinal value.
     * @return Enumerated value.
     */
    @Nullable public static GridClosureCallMode fromOrdinal(byte ord) {
        return ord >= 0 && ord < VALS.length ? VALS[ord] : null;
    }
}