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 gobblin.data.management.retention.action; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.util.List; import org.apache.commons.lang3.StringUtils; import org.apache.hadoop.fs.FileSystem; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableList; import com.typesafe.config.Config; import gobblin.data.management.dataset.Dataset; import gobblin.data.management.policy.VersionSelectionPolicy; import gobblin.data.management.retention.dataset.ConfigurableCleanableDataset; import gobblin.data.management.retention.dataset.FsCleanableHelper; import gobblin.data.management.version.DatasetVersion; import gobblin.data.management.version.finder.VersionFinder; import gobblin.dataset.DatasetsFinder; import gobblin.util.ClassAliasResolver; import gobblin.util.ConfigUtils; import gobblin.util.reflection.GobblinConstructorUtils; /** * An abstraction to perform a retention action for a subset of {@link DatasetVersion}s. * A few kinds of actions are deletion, access control, encryption, archival etc. */ public abstract class RetentionAction { protected final FileSystem fs; @SuppressWarnings("rawtypes") protected final ClassAliasResolver<VersionSelectionPolicy> versionSelectionAliasResolver; protected final boolean isSimulateMode; public RetentionAction(Config actionConfig, FileSystem fs, Config jobConfig) { this.versionSelectionAliasResolver = new ClassAliasResolver<>(VersionSelectionPolicy.class); this.fs = fs; this.isSimulateMode = ConfigUtils.getBoolean(jobConfig, FsCleanableHelper.SIMULATE_KEY, Boolean.valueOf(FsCleanableHelper.SIMULATE_DEFAULT)); } /** * Execute the action on all {@link DatasetVersion}s or a subset of {@link DatasetVersion}s. Each {@link Dataset} * uses the {@link VersionFinder} to find all the {@link DatasetVersion}s and calls this method to perform the necessary * action on those {@link DatasetVersion}s * <p> * <b>Note</b> Any kind of {@link VersionSelectionPolicy} has <b>NOT</b> been applied to the list of {@link DatasetVersion}s * being passed. It is the responsibility of the {@link RetentionAction} to filter the {@link DatasetVersion}s by * applying {@link VersionSelectionPolicy}s and then perform the action. * </p> * @param allVersions list of all {@link DatasetVersion}s found by the {@link DatasetsFinder}. */ public abstract void execute(List<DatasetVersion> allVersions) throws IOException; /** * A factory to create new {@link RetentionAction}s * */ public interface RetentionActionFactory { /** * A factory method to create a new {@link RetentionAction} using a <code>config</code>. The {@link Dataset} always * calls {@link #canCreateWithConfig(Config)} before calling this method. * * @param config to use to create the {@link RetentionAction} * @return A new {@link RetentionAction} */ RetentionAction createRetentionAction(Config config, FileSystem fs, Config jobConfig); /** * Method to check if a {@link RetentionAction} can be created/instantiated with the <code>config</code>. * If the specific type of {@link RetentionAction} has been specified in the configuration the method returns * <code>true</code> * If the method returns <code>true</code>, {@link #createRetentionAction(Config, FileSystem)} can be called to create * this {@link RetentionAction}. * * @param config to use to create the {@link RetentionAction} * @param jobConfig is the job level config * @return true if the specific type of {@link RetentionAction} has been specified in the configuration, false otherwise */ boolean canCreateWithConfig(Config config); } /* * Since {@link VersionSelectionPolicy} does not have a factory to create new objects we need to use the legacy * pattern of creating new objects using GobblinConstructorUtils */ @SuppressWarnings("unchecked") protected VersionSelectionPolicy<DatasetVersion> createSelectionPolicy(Config selectionConfig, Config jobConfig) { try { String selectionPolicyKey = StringUtils.substringAfter( ConfigurableCleanableDataset.SELECTION_POLICY_CLASS_KEY, ConfigurableCleanableDataset.CONFIGURATION_KEY_PREFIX); Preconditions.checkArgument(selectionConfig.hasPath(selectionPolicyKey)); String className = selectionConfig.getString(selectionPolicyKey); return (VersionSelectionPolicy<DatasetVersion>) GobblinConstructorUtils.invokeFirstConstructor( this.versionSelectionAliasResolver.resolveClass(className), ImmutableList.<Object>of(selectionConfig), ImmutableList.<Object>of(selectionConfig, ConfigUtils.configToProperties(jobConfig)), ImmutableList.<Object>of(ConfigUtils.configToProperties(jobConfig))); } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException | InstantiationException | ClassNotFoundException e) { throw new IllegalArgumentException(e); } } }