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.drill.common.logical; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.drill.common.config.DrillConfig; import org.apache.drill.common.exceptions.LogicalPlanParsingException; import org.apache.drill.common.logical.OperatorGraph.OpNode; import org.apache.drill.common.logical.data.LogicalOperator; import org.apache.drill.common.logical.graph.GraphAlgos; import org.apache.drill.common.util.FileUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.fasterxml.jackson.annotation.JsonCreator; import com.fasterxml.jackson.annotation.JsonIgnore; import com.fasterxml.jackson.annotation.JsonProperty; import com.fasterxml.jackson.annotation.JsonPropertyOrder; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.google.common.base.Charsets; import com.google.common.base.Function; import com.google.common.collect.Iterables; import com.google.common.collect.Lists; import com.google.common.io.Files; @JsonPropertyOrder({ "head", "storage", "query" }) public class LogicalPlan { static final Logger logger = LoggerFactory.getLogger(LogicalPlan.class); private final PlanProperties properties; private final Map<String, StorageEngineConfig> storageEngines; private final OperatorGraph graph; private static volatile ObjectMapper MAPPER; @SuppressWarnings("unchecked") @JsonCreator public LogicalPlan(@JsonProperty("head") PlanProperties head, @JsonProperty("storage") List<StorageEngineConfig> storageEngines, @JsonProperty("query") List<LogicalOperator> operators) { if (storageEngines == null) storageEngines = Collections.EMPTY_LIST; this.properties = head; this.storageEngines = new HashMap<String, StorageEngineConfig>(storageEngines.size()); for (StorageEngineConfig store : storageEngines) { StorageEngineConfig old = this.storageEngines.put(store.getName(), store); if (old != null) throw new LogicalPlanParsingException(String.format( "Each storage engine must have a unique name. You provided more than one data source with the same name of '%s'", store.getName())); } this.graph = new OperatorGraph(operators); } @JsonProperty("query") public List<LogicalOperator> getSortedOperators() { List<OpNode> nodes = GraphAlgos.TopoSorter.sort(graph.getAdjList()); Iterable<LogicalOperator> i = Iterables.transform(nodes, new Function<OpNode, LogicalOperator>() { public LogicalOperator apply(OpNode o) { return o.getNodeValue(); } }); return Lists.newArrayList(i); } public StorageEngineConfig getStorageEngine(String name) { StorageEngineConfig ds = storageEngines.get(name); if (ds == null) throw new LogicalPlanParsingException(String.format("Unknown data source named [%s].", name)); return ds; } @JsonIgnore public OperatorGraph getGraph() { return graph; } @JsonProperty("head") public PlanProperties getProperties() { return properties; } @JsonProperty("storage") public List<StorageEngineConfig> getStorageEngines() { return new ArrayList<StorageEngineConfig>(storageEngines.values()); } // public static LogicalPlan readFromString(String planString, DrillConfig config) throws JsonParseException, JsonMappingException, IOException{ // ObjectMapper mapper = config.getMapper(); // LogicalPlan plan = mapper.readValue(planString, LogicalPlan.class); // return plan; // } // // public static LogicalPlan readFromResourcePath(String fileName, DrillConfig config) throws IOException{ // URL u = LogicalPlan.class.getResource(fileName); // if(u == null) throw new FileNotFoundException(String.format("Unable to find file on path %s", fileName)); // return readFromFile(u.getFile(), config); // } // // public static LogicalPlan readFromFile(String fileName, DrillConfig config) throws IOException{ // String planString = Files.toString(new File(fileName), Charsets.UTF_8); // return readFromString(planString, config); // } // public String toJsonString(DrillConfig config) throws JsonProcessingException { return config.getMapper().writeValueAsString(this); } public static void main(String[] args) throws Exception { DrillConfig config = DrillConfig.create(); String externalPlan = Files.toString(FileUtils.getResourceAsFile("/simple_join.json"), Charsets.UTF_8); LogicalPlan plan = parse(config, externalPlan); } /** Parses a logical plan. */ public static LogicalPlan parse(DrillConfig config, String planString) { ObjectMapper mapper = config.getMapper(); try { LogicalPlan plan = mapper.readValue(planString, LogicalPlan.class); System.out.println(mapper.writeValueAsString(plan)); return plan; } catch (IOException e) { throw new RuntimeException(e); } } /** Converts a logical plan to a string. (Opposite of {@link #parse}.) */ public String unparse(DrillConfig config) { try { return config.getMapper().writeValueAsString(this); } catch (JsonProcessingException e) { throw new RuntimeException(e); } } }