content: /*
   *  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.asterix.external.library;
  
  import java.io.File;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.net.MalformedURLException;
  import java.net.URL;
  
  import org.apache.asterix.common.functions.ExternalFunctionLanguage;
  import org.apache.asterix.common.library.ILibrary;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  public class JavaLibrary implements ILibrary {
  
      private final ExternalLibraryClassLoader cl;
  
      private static final Logger LOGGER = LogManager.getLogger();
  
      public JavaLibrary(File libDir) throws HyracksDataException, MalformedURLException {
  
          FilenameFilter jarFileFilter = (dir, name) -> name.endsWith(".jar");
  
          // Get the jar file <Allow only a single jar file>
          String[] jarsInLibDir = libDir.list(jarFileFilter);
          if (jarsInLibDir.length > 1) {
              throw new HyracksDataException("Incorrect library structure: found multiple library jars");
          }
          if (jarsInLibDir.length <= 0) {
              throw new HyracksDataException("Incorrect library structure: could not find library jar");
          }
  
          File libJar = new File(libDir, jarsInLibDir[0]);
          // get the jar dependencies
          File libDependencyDir = new File(libDir.getAbsolutePath() + File.separator + "lib");
          int numDependencies = 1;
          String[] libraryDependencies = null;
          if (libDependencyDir.exists()) {
              libraryDependencies = libDependencyDir.list(jarFileFilter);
              numDependencies += libraryDependencies.length;
          }
  
          ClassLoader parentClassLoader = JavaLibrary.class.getClassLoader();
          URL[] urls = new URL[numDependencies];
          int count = 0;
          // get url of library
          urls[count++] = libJar.toURI().toURL();
  
          // get urls for dependencies
          if (libraryDependencies != null && libraryDependencies.length > 0) {
              for (String dependency : libraryDependencies) {
                  File file = new File(libDependencyDir + File.separator + dependency);
                  urls[count++] = file.toURI().toURL();
              }
          }
  
          // create and return the class loader
          this.cl = new ExternalLibraryClassLoader(urls, parentClassLoader);
  
      }
  
      @Override
      public ExternalFunctionLanguage getLanguage() {
          return ExternalFunctionLanguage.JAVA;
      }
  
      public ClassLoader getClassLoader() {
          return cl;
      }
  
      public void close() {
          try {
              if (cl != null) {
                  cl.close();
              }
          } catch (IOException e) {
              LOGGER.error("Couldn't close classloader", e);
          }
      }
  
  }
  