Java tutorial
/** * 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.falcon.extensions.mirroring.hdfs; import org.apache.commons.lang3.StringUtils; import org.apache.falcon.FalconException; import org.apache.falcon.entity.ClusterHelper; import org.apache.falcon.entity.v0.cluster.Cluster; import org.apache.falcon.extensions.AbstractExtension; import java.util.Properties; /** * Hdfs mirroring extension. */ public class HdfsMirroringExtension extends AbstractExtension { private static final String COMMA_SEPARATOR = ","; private static final String EXTENSION_NAME = "HDFS-MIRRORING"; @Override public String getName() { return EXTENSION_NAME; } @Override public void validate(final Properties extensionProperties) throws FalconException { for (HdfsMirroringExtensionProperties option : HdfsMirroringExtensionProperties.values()) { if (extensionProperties.getProperty(option.getName()) == null && option.isRequired()) { throw new FalconException("Missing extension property: " + option.getName()); } } } @Override public Properties getAdditionalProperties(final Properties extensionProperties) throws FalconException { Properties additionalProperties = new Properties(); // Add default properties if not passed String distcpMaxMaps = extensionProperties.getProperty(HdfsMirroringExtensionProperties.MAX_MAPS.getName()); if (StringUtils.isBlank(distcpMaxMaps)) { additionalProperties.put(HdfsMirroringExtensionProperties.MAX_MAPS.getName(), "1"); } String distcpMapBandwidth = extensionProperties .getProperty(HdfsMirroringExtensionProperties.MAP_BANDWIDTH_IN_MB.getName()); if (StringUtils.isBlank(distcpMapBandwidth)) { additionalProperties.put(HdfsMirroringExtensionProperties.MAP_BANDWIDTH_IN_MB.getName(), "100"); } // Construct fully qualified hdfs src path String srcPaths = extensionProperties.getProperty(HdfsMirroringExtensionProperties.SOURCE_DIR.getName()); StringBuilder absoluteSrcPaths = new StringBuilder(); String sourceClusterName = extensionProperties .getProperty(HdfsMirroringExtensionProperties.SOURCE_CLUSTER.getName()); // Since source cluster get read interface Cluster srcCluster = ClusterHelper.getCluster(sourceClusterName); if (srcCluster == null) { throw new FalconException("Cluster entity " + sourceClusterName + " not found"); } String srcClusterEndPoint = ClusterHelper.getReadOnlyStorageUrl(srcCluster); if (StringUtils.isNotBlank(srcPaths)) { String[] paths = srcPaths.split(COMMA_SEPARATOR); for (String path : paths) { StringBuilder srcpath = new StringBuilder(srcClusterEndPoint); srcpath.append(path.trim()); srcpath.append(COMMA_SEPARATOR); absoluteSrcPaths.append(srcpath); } } additionalProperties.put(HdfsMirroringExtensionProperties.SOURCE_DIR.getName(), StringUtils.removeEnd(absoluteSrcPaths.toString(), COMMA_SEPARATOR)); // add sourceClusterFS and targetClusterFS additionalProperties.put(HdfsMirroringExtensionProperties.SOURCE_CLUSTER_FS_WRITE_ENDPOINT.getName(), ClusterHelper.getStorageUrl(srcCluster)); String targetClusterName = extensionProperties .getProperty(HdfsMirroringExtensionProperties.TARGET_CLUSTER.getName()); Cluster targetCluster = ClusterHelper.getCluster(targetClusterName); if (targetCluster == null) { throw new FalconException("Cluster entity " + targetClusterName + " not found"); } additionalProperties.put(HdfsMirroringExtensionProperties.TARGET_CLUSTER_FS_WRITE_ENDPOINT.getName(), ClusterHelper.getStorageUrl(targetCluster)); return additionalProperties; } }