Java tutorial
/** * Copyright 2017 Goldman Sachs. * 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. */ package com.gs.obevo.api.factory; import java.net.URL; import com.gs.obevo.api.platform.DeployerRuntimeException; import com.gs.obevo.util.vfs.FileObject; import com.gs.obevo.util.vfs.FileRetrievalMode; import org.apache.commons.configuration2.CombinedConfiguration; import org.apache.commons.configuration2.FixedYAMLConfiguration; import org.apache.commons.configuration2.HierarchicalConfiguration; import org.apache.commons.configuration2.ImmutableHierarchicalConfiguration; import org.apache.commons.configuration2.builder.FileBasedConfigurationBuilder; import org.apache.commons.configuration2.builder.fluent.Parameters; import org.apache.commons.configuration2.ex.ConfigurationException; import org.apache.commons.configuration2.tree.ImmutableNode; import org.apache.commons.configuration2.tree.OverrideCombiner; import org.eclipse.collections.api.RichIterable; import org.eclipse.collections.api.bag.MutableBag; import org.eclipse.collections.api.block.function.Function; import org.eclipse.collections.api.block.predicate.Predicate; import org.eclipse.collections.api.block.procedure.Procedure2; import org.eclipse.collections.api.list.ListIterable; import org.eclipse.collections.api.list.MutableList; import org.eclipse.collections.api.multimap.list.MutableListMultimap; import org.eclipse.collections.api.set.MutableSet; import org.eclipse.collections.impl.block.factory.HashingStrategies; import org.eclipse.collections.impl.block.factory.primitive.IntPredicates; import org.eclipse.collections.impl.collection.mutable.CollectionAdapter; import org.eclipse.collections.impl.factory.HashingStrategySets; import org.eclipse.collections.impl.factory.Lists; import org.eclipse.collections.impl.list.fixed.ArrayAdapter; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Utility to read in properties from default and override locations. */ class PlatformConfigReader { private static final Logger LOG = LoggerFactory.getLogger(PlatformConfigReader.class); private static final String PROP_CONFIG_PRIORITY = "obevo.configPriority"; public ImmutableHierarchicalConfiguration readPlatformProperties(RichIterable<String> configPackages) { MutableList<PropertyInput> prioritizedProperties = readConfigPackages(configPackages); validate(prioritizedProperties); // order properties by priority: higher-numbered files will replace properties of lower-numbered files prioritizedProperties.sortThisBy(new Function<PropertyInput, Integer>() { @Override public Integer valueOf(PropertyInput propertyInput1) { return propertyInput1.getPriority(); } }).reverseThis(); // needs to be reversed as CombinedConfiguration takes the higher-priority files first // merge properties CombinedConfiguration combinedConfiguration = new CombinedConfiguration(new OverrideCombiner()); for (HierarchicalConfiguration<ImmutableNode> properties : prioritizedProperties .collect(new Function<PropertyInput, HierarchicalConfiguration<ImmutableNode>>() { @Override public HierarchicalConfiguration<ImmutableNode> valueOf(PropertyInput propertyInput) { return propertyInput.getProps(); } })) { combinedConfiguration.addConfiguration(properties); } // remove the configPriority property combinedConfiguration.clearTree(PROP_CONFIG_PRIORITY); return combinedConfiguration; } private MutableList<PropertyInput> readConfigPackages(RichIterable<String> configPackages) { MutableSet<PropertyInput> prioritizedProperties = HashingStrategySets.mutable .of(HashingStrategies.fromFunction(new Function<PropertyInput, URL>() { @Override public URL valueOf(PropertyInput propertyInput) { return propertyInput.getPropertyFilePath(); } })); for (String configPackage : configPackages) { ListIterable<FileObject> fileObjects = FileRetrievalMode.CLASSPATH.resolveFileObjects(configPackage) .flatCollect(new Function<FileObject, Iterable<FileObject>>() { @Override public Iterable<FileObject> valueOf(FileObject object) { return ArrayAdapter.adapt(object.getChildren()); } }); ListIterable<FileObject> propertyFiles = fileObjects.select(new Predicate<FileObject>() { @Override public boolean accept(FileObject it) { return it.getName().getExtension().equals("yaml"); } }); for (FileObject propertyFile : propertyFiles) { HierarchicalConfiguration<ImmutableNode> fileProps = loadPropertiesFromUrl(propertyFile); String configPriorityProp = fileProps.getString(PROP_CONFIG_PRIORITY); if (configPriorityProp != null) { int priority = Integer.parseInt(configPriorityProp); prioritizedProperties.add(new PropertyInput(propertyFile.getName().getBaseName(), propertyFile.getURLDa(), priority, fileProps)); } else { LOG.warn("Property file {} was ignored as it did not contain {} property", propertyFile, PROP_CONFIG_PRIORITY); } } } return prioritizedProperties.toList(); } private void validate(MutableList<PropertyInput> prioritizedProperties) { // Now validate the file inputs if (prioritizedProperties.isEmpty()) { throw new IllegalStateException("Could not find default configuration " + "abc" + " in the classpath"); } MutableListMultimap<String, PropertyInput> propertiesByFileName = prioritizedProperties .groupBy(new Function<PropertyInput, String>() { @Override public String valueOf(PropertyInput propertyInput) { return propertyInput.getFileName(); } }); final MutableList<String> warnings = Lists.mutable.empty(); final MutableList<String> errors = Lists.mutable.empty(); propertiesByFileName.forEachKeyMultiValues(new Procedure2<String, Iterable<PropertyInput>>() { @Override public void value(String fileName, Iterable<PropertyInput> propertyInputsIter) { MutableList<PropertyInput> propertyInputs = CollectionAdapter.wrapList(propertyInputsIter); MutableBag<Integer> priorities = propertyInputs.collect(new Function<PropertyInput, Integer>() { @Override public Integer valueOf(PropertyInput propertyInput1) { return propertyInput1.getPriority(); } }).toBag(); MutableBag<Integer> duplicatePriorities = priorities .selectByOccurrences(IntPredicates.greaterThan(1)); if (duplicatePriorities.notEmpty()) { errors.add("File name [" + fileName + "] was found with the same priority [" + duplicatePriorities + "] in multiple locations [" + propertyInputs.collect(new Function<PropertyInput, URL>() { @Override public URL valueOf(PropertyInput propertyInput) { return propertyInput.getPropertyFilePath(); } }) + "]. Please ensure that priorities are distinct."); } else if (priorities.size() > 1) { warnings.add("File name [" + fileName + "] was found in multiple locations [" + propertyInputs.collect(new Function<PropertyInput, URL>() { @Override public URL valueOf(PropertyInput propertyInput) { return propertyInput.getPropertyFilePath(); } }) + "]. Will refer to them in their priority order, but ideally the file name should be different."); } } }); if (warnings.notEmpty()) { LOG.warn( "Warnings on platform configuration file setup; please address in the future, but program will proceed:\n{}", warnings.makeString("\n")); } if (errors.notEmpty()) { throw new IllegalStateException(errors.makeString("abc")); } } private HierarchicalConfiguration<ImmutableNode> loadPropertiesFromUrl(FileObject file) { try { return new FileBasedConfigurationBuilder<>(FixedYAMLConfiguration.class) .configure(new Parameters().hierarchical().setURL(file.getURLDa())).getConfiguration(); } catch (ConfigurationException e) { throw new DeployerRuntimeException(e); } } private static class PropertyInput { private final String fileName; private final URL propertyFilePath; private final int priority; private final HierarchicalConfiguration<ImmutableNode> props; PropertyInput(String fileName, URL propertyFilePath, int priority, HierarchicalConfiguration<ImmutableNode> props) { this.fileName = fileName; this.propertyFilePath = propertyFilePath; this.priority = priority; this.props = props; } String getFileName() { return fileName; } URL getPropertyFilePath() { return propertyFilePath; } int getPriority() { return priority; } HierarchicalConfiguration<ImmutableNode> getProps() { return props; } } }