quickstart.DataPersistence Maven / Gradle / Ivy
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/*
* Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
*
* Licensed 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. See accompanying
* LICENSE file.
*/
package quickstart;
import java.io.File;
import com.gemstone.gemfire.cache.Cache;
import com.gemstone.gemfire.cache.CacheFactory;
import com.gemstone.gemfire.cache.DiskStore;
import com.gemstone.gemfire.cache.Region;
/**
* This example shows the persistence of cached data to disk. Persisted data
* provides a backup of the cached data and can be used to initialize a data
* region at creation time. Please refer to the quickstart guide for
* instructions on how to run this example.
*
*
* @author GemStone Systems, Inc.
* @since 4.1.1
*/
public class DataPersistence {
public static void main(String[] args) throws Exception {
System.out.println("This example shows persistence of region data to disk.");
// create the directory where data is going to be stored
File dir = new File("persistData1");
dir.mkdir();
System.out.println();
System.out.println("Connecting to the distributed system and creating the cache.");
// Create the cache which causes the cache-xml-file to be parsed
Cache cache = new CacheFactory()
.set("name", "DataPersistence")
.set("cache-xml-file", "xml/DataPersistence.xml")
.set("enable-network-partition-detection", "true")
.create();
// Get the exampleRegion
Region exampleRegion = cache.getRegion("exampleRegion");
System.out.println();
System.out.println("Example region \"" + exampleRegion.getFullPath() + "\" created in cache. ");
// Get persistDir from attributes of exampleRegion
String diskStoreName = exampleRegion.getAttributes().getDiskStoreName();
DiskStore ds1 = cache.findDiskStore(diskStoreName);
if (ds1 == null) {
return;
}
File[] persistDir = ds1.getDiskDirs();
String persistDirString = "";
for (int i = 0; i < persistDir.length; i++) {
if (i > 0) {
persistDirString += ", ";
}
persistDirString += persistDir[i];
}
System.out.println();
System.out.println("Look in " + persistDirString + " to see the files used for region ");
System.out.println("persistence.");
// Try to obtain the value for the "key"
String key = "key1";
System.out.println();
System.out.println("Getting value for " + key);
String value = exampleRegion.get(key);
if (value == null) {
System.out.println("No value found for key " + key + ". Get operation returned null.");
// Create initial value to put...
value = "value1";
}
else {
System.out.println("Get returned value: " + value);
// Increment value to update...
value = "value" + (Integer.parseInt(value.substring(5)) + 1);
}
System.out.println();
System.out.println("Putting entry: " + key + ", " + value);
exampleRegion.put(key, value);
// Close the cache and disconnect from GemFire distributed system
System.out.println();
System.out.println("Closing the cache and disconnecting.");
cache.close();
System.out.println();
System.out.println("Each time you run this program, if the disk files are available, they");
System.out.println("will be used to initialize the region.");
}
}