/
ComputeClosureExample.java
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/
ComputeClosureExample.java
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/*
* 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.examples.compute;
import org.apache.ignite.*;
import org.apache.ignite.examples.*;
import org.apache.ignite.lang.*;
import java.util.*;
/**
* Demonstrates a simple use of Ignite with reduce closure.
* <p>
* This example splits a phrase into collection of words, computes their length on different
* nodes and then computes total amount of non-whitespaces characters in the phrase.
* <p>
* Remote nodes should always be started with special configuration file which
* enables P2P class loading: {@code 'ignite.{sh|bat} examples/config/example-compute.xml'}.
* <p>
* Alternatively you can run {@link ComputeNodeStartup} in another JVM which will start node
* with {@code examples/config/example-compute.xml} configuration.
*/
public class ComputeClosureExample {
/**
* Executes example.
*
* @param args Command line arguments, none required.
* @throws Exception If example execution failed.
*/
public static void main(String[] args) throws Exception {
try (Ignite ignite = Ignition.start("examples/config/example-compute.xml")) {
System.out.println();
System.out.println(">>> Compute closure example started.");
// Execute closure on all cluster nodes.
Collection<Integer> res = ignite.compute().apply(
new IgniteClosure<String, Integer>() {
@Override public Integer apply(String word) {
System.out.println();
System.out.println(">>> Printing '" + word + "' on this node from ignite job.");
// Return number of letters in the word.
return word.length();
}
},
// Job parameters. Ignite will create as many jobs as there are parameters.
Arrays.asList("Count characters using closure".split(" "))
);
int sum = 0;
// Add up individual word lengths received from remote nodes
for (int len : res)
sum += len;
System.out.println();
System.out.println(">>> Total number of characters in the phrase is '" + sum + "'.");
System.out.println(">>> Check all nodes for output (this node is also part of the cluster).");
}
}
}