| /* |
| * 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.exec.expr.fn; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.StringReader; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.drill.shaded.guava.com.google.common.annotations.VisibleForTesting; |
| import org.apache.drill.common.exceptions.UserException; |
| import org.apache.drill.common.util.DrillFileUtils; |
| import org.codehaus.commons.compiler.CompileException; |
| import org.codehaus.janino.Java.CompilationUnit; |
| import org.codehaus.janino.Parser; |
| import org.codehaus.janino.Scanner; |
| import org.eclipse.jetty.util.IO; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * To avoid the cost of initializing all functions up front, this class contains |
| * all information required to initializing a function when it is used. |
| */ |
| public class FunctionInitializer { |
| private static final Logger logger = LoggerFactory.getLogger(FunctionInitializer.class); |
| |
| private final String className; |
| private final ClassLoader classLoader; |
| private Map<String, String> methods; |
| private List<String> imports; |
| private volatile boolean isLoaded; |
| |
| /** |
| * @param className |
| * the fully qualified name of the class implementing the function |
| * @param classLoader |
| * class loader associated with the function, is unique for each jar |
| * that holds function to prevent classpath collisions during loading |
| * an unloading jars |
| */ |
| public FunctionInitializer(String className, ClassLoader classLoader) { |
| this.className = className; |
| this.classLoader = classLoader; |
| } |
| |
| /** |
| * @return returns class loader |
| */ |
| public ClassLoader getClassLoader() { return classLoader; } |
| |
| /** |
| * @return the fully qualified name of the class implementing the function |
| */ |
| public String getClassName() { |
| return className; |
| } |
| |
| /** |
| * @return the imports of this class (for java code gen) |
| */ |
| public List<String> getImports() { |
| loadFunctionBody(); |
| return imports; |
| } |
| |
| /** |
| * @param methodName method name |
| * @return the content of the method (for java code gen inlining) |
| */ |
| public String getMethod(String methodName) { |
| loadFunctionBody(); |
| return methods.get(methodName); |
| } |
| |
| /** |
| * Loads function body: methods (for instance, eval, setup, reset) and imports. |
| * Loading is done once per class instance upon first function invocation. |
| * Double-checked locking is used to avoid concurrency issues |
| * when two threads are trying to load the function body at the same time. |
| */ |
| private void loadFunctionBody() { |
| if (isLoaded) { |
| return; |
| } |
| |
| synchronized (this) { |
| if (isLoaded) { |
| return; |
| } |
| |
| logger.trace("Getting function body for the {}", className); |
| try { |
| final Class<?> clazz = Class.forName(className, true, classLoader); |
| final CompilationUnit cu = convertToCompilationUnit(clazz); |
| |
| methods = MethodGrabbingVisitor.getMethods(cu, clazz); |
| imports = ImportGrabber.getImports(cu); |
| isLoaded = true; |
| |
| } catch (IOException | ClassNotFoundException e) { |
| throw UserException.functionError(e) |
| .message("Failure reading Function class.") |
| .addContext("Function Class", className) |
| .build(logger); |
| } |
| } |
| } |
| |
| /** |
| * Using class name generates path to class source code (*.java), |
| * reads its content as string and parses it into {@link org.codehaus.janino.Java.CompilationUnit}. |
| * |
| * @param clazz function class |
| * @return compilation unit |
| * @throws IOException if did not find class or could not load it |
| */ |
| @VisibleForTesting |
| CompilationUnit convertToCompilationUnit(Class<?> clazz) throws IOException { |
| String path = clazz.getName(); |
| path = path.replaceFirst("\\$.*", ""); |
| path = path.replace(".", DrillFileUtils.SEPARATOR); |
| path = "/" + path + ".java"; |
| |
| logger.trace("Loading function code from the {}", path); |
| try (InputStream is = clazz.getResourceAsStream(path)) { |
| if (is == null) { |
| throw new IOException(String.format( |
| "Failure trying to locate source code for class %s, tried to read on classpath location %s", clazz.getName(), |
| path)); |
| } |
| String body = IO.toString(is); |
| |
| // TODO: Hack to remove annotations so Janino doesn't choke. Need to reconsider this problem... |
| body = body.replaceAll("@\\w+(?:\\([^\\\\]*?\\))?", ""); |
| try { |
| return (CompilationUnit) new Parser(new Scanner(null, new StringReader(body))).parseAbstractCompilationUnit(); |
| } catch (CompileException e) { |
| throw new IOException(String.format("Failure while loading class %s.", clazz.getName()), e); |
| } |
| |
| } |
| |
| } |
| |
| } |