| /* |
| * 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.compute; |
| |
| import java.util.Collection; |
| import java.util.List; |
| import java.util.Map; |
| import org.apache.ignite.IgniteException; |
| import org.apache.ignite.cluster.ClusterNode; |
| import org.apache.ignite.internal.util.typedef.F; |
| import org.apache.ignite.internal.util.typedef.internal.U; |
| import org.apache.ignite.resources.LoadBalancerResource; |
| import org.jetbrains.annotations.NotNull; |
| |
| /** |
| * This class defines simplified adapter for {@link ComputeTask}. This adapter can be used |
| * when jobs can be randomly assigned to available grid nodes. This adapter is sufficient |
| * in most homogeneous environments where all nodes are equally suitable for executing grid |
| * job. See {@link #split(int, Object)} method for more details. |
| * <p> |
| * Below is a coding example of how you would use {@code ComputeTaskSplitAdapter}: |
| * <pre name="code" class="java"> |
| * public class MyFooBarTask extends ComputeTaskSplitAdapter<Object, String> { |
| * @Override |
| * protected Collection<? extends ComputeJob> split(int gridSize, Object arg) throws IgniteCheckedException { |
| * List<MyFooBarJob> jobs = new ArrayList<MyFooBarJob>(gridSize); |
| * |
| * for (int i = 0; i < gridSize; i++) { |
| * jobs.add(new MyFooBarJob(arg)); |
| * } |
| * |
| * // Node assignment via load balancer |
| * // happens automatically. |
| * return jobs; |
| * } |
| * |
| * // Aggregate results into one compound result. |
| * public String reduce(List<ComputeJobResult> results) throws IgniteCheckedException { |
| * // For the purpose of this example we simply |
| * // concatenate string representation of every |
| * // job result |
| * StringBuilder buf = new StringBuilder(); |
| * |
| * for (ComputeJobResult res : results) { |
| * // Append string representation of result |
| * // returned by every job. |
| * buf.append(res.getData().string()); |
| * } |
| * |
| * return buf.string(); |
| * } |
| * } |
| * </pre> |
| * @param <T> Type of the task execution argument. |
| * @param <R> Type of the task result returning from {@link ComputeTask#reduce(List)} method. |
| */ |
| public abstract class ComputeTaskSplitAdapter<T, R> extends ComputeTaskAdapter<T, R> { |
| /** */ |
| private static final long serialVersionUID = 0L; |
| |
| /** Load balancer. */ |
| @LoadBalancerResource |
| private ComputeLoadBalancer balancer; |
| |
| /** |
| * This is a simplified version of {@link ComputeTask#map(List, Object)} method. |
| * <p> |
| * This method basically takes given argument and splits it into a collection |
| * of {@link ComputeJob} using provided grid size as indication of how many node are |
| * available. These jobs will be randomly mapped to available grid nodes. Note that |
| * if number of jobs is greater than number of grid nodes (i.e, grid size), the grid |
| * nodes will be reused and some jobs will end up on the same grid nodes. |
| * |
| * @param gridSize Number of available grid nodes. Note that returned number of |
| * jobs can be less, equal or greater than this grid size. |
| * @param arg Task execution argument. Can be {@code null}. |
| * @return Collection of grid jobs. These jobs will be randomly mapped to |
| * available grid nodes. Note that if number of jobs is greater than number of |
| * grid nodes (i.e, grid size), the grid nodes will be reused and some jobs |
| * will end up on the same grid nodes. |
| * @throws IgniteException Thrown in case of any errors. |
| * |
| * @see ComputeTask#map(List, Object) |
| */ |
| protected abstract Collection<? extends ComputeJob> split(int gridSize, T arg) throws IgniteException; |
| |
| /** {@inheritDoc} */ |
| @NotNull @Override public final Map<? extends ComputeJob, ClusterNode> map(List<ClusterNode> subgrid, T arg) { |
| assert subgrid != null; |
| assert !subgrid.isEmpty(); |
| |
| Collection<? extends ComputeJob> jobs = split(subgrid.size(), arg); |
| |
| if (F.isEmpty(jobs)) |
| throw new IgniteException("Split returned no jobs."); |
| |
| Map<ComputeJob, ClusterNode> map = U.newHashMap(jobs.size()); |
| |
| for (ComputeJob job : jobs) { |
| ClusterNode old = map.put(job, balancer.getBalancedNode(job, null)); |
| |
| if (old != null) |
| throw new IgniteException("Failed to map task (same job instance is being mapped more than once) " + |
| "[job=" + job + ", task=" + this + ']'); |
| } |
| |
| return map; |
| } |
| } |