CollisionJobContext.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.spi.collision;

import org.apache.ignite.compute.ComputeJob;
import org.apache.ignite.compute.ComputeJobContext;
import org.apache.ignite.compute.ComputeTaskSession;

/**
 * This interface defines set of operations that collision SPI implementation can perform on
 * jobs that are either waiting or executing.
 */
public interface CollisionJobContext {
    /**
     * Gets current task session associated with this job.
     *
     * @return Grid task session.
     */
    public ComputeTaskSession getTaskSession();

    /**
     * Gets job context. Use this context to set/get attributes that
     * should be visible only to this job and should not be distributed
     * to other jobs in the grid.
     * <p>
     * Job context travels with job whenever it gets failed-over to another
     * node, so attributes set on the context on one node will be visible
     * on other nodes this job may potentially end up on.
     *
     * @return Job context.
     */
    public ComputeJobContext getJobContext();

    /**
     * Job for this context.
     *
     * @return Job for this context.
     */
    public ComputeJob getJob();

    /**
     * Activates the job. If job is already active this is no-op. Collision resolution
     * is handled concurrently, so it may be possible that other threads already activated
     * or cancelled/rejected this job. This method will return {@code true} if it was
     * able to activate the job, and {@code false} otherwise.
     *
     * @return {@code True} if it was possible to activate the job, and
     *      {@code false} otherwise.
     */
    public boolean activate();

    /**
     * Cancels the job. If job was active (executing) method {@link org.apache.ignite.compute.ComputeJob#cancel()} will
     * be called on the job. If job was in wait state, then it will be {@code rejected}
     * prior to execution and {@link org.apache.ignite.compute.ComputeJob#cancel()} will not be called.
     * <p>
     * Collision resolution is handled concurrently, so it may be possible that other threads
     * already activated or cancelled/rejected this job. This method will return {@code true}
     * if it was able to cancel/reject the job and {@code false} otherwise.
     *
     * @return {@code True} if it was possible to cancel/reject this job, {@code false}
     *      otherwise.
     */
    public boolean cancel();
}