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
   *
   *      https://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.tools.ant.taskdefs.optional.extension;
  
  import java.io.File;
  import java.util.List;
  import java.util.Vector;
  
  import org.apache.tools.ant.BuildException;
  import org.apache.tools.ant.DirectoryScanner;
  import org.apache.tools.ant.Task;
  import org.apache.tools.ant.types.FileSet;
  
  /**
   * Displays the "Optional Package" and "Package Specification" information
   * contained within the specified JARs.
   *
   * <p>Prior to JDK1.3, an "Optional Package" was known as an Extension.
   * The specification for this mechanism is available in the JDK1.3
   * documentation in the directory
   * $JDK_HOME/docs/guide/extensions/versioning.html. Alternatively it is
   * available online at <a href="https://docs.oracle.com/javase/8/docs/technotes/guides/extensions/versioning.html">
   * https://docs.oracle.com/javase/8/docs/technotes/guides/extensions/versioning.html</a>.</p>
   *
   * @ant.task name="jarlib-display"
   */
  public class JarLibDisplayTask extends Task {
      /**
       * The library to display information about.
       */
      private File libraryFile;
  
      /**
       * Filesets specifying all the libraries
       * to display information about.
       */
      private final List<FileSet> libraryFileSets = new Vector<>();
  
      /**
       * The JAR library to display information for.
       *
       * @param file The jar library to display information for.
       */
      public void setFile(final File file) {
          this.libraryFile = file;
      }
  
      /**
       * Adds a set of files about which library data will be displayed.
       *
       * @param fileSet a set of files about which library data will be displayed.
       */
      public void addFileset(final FileSet fileSet) {
          libraryFileSets.add(fileSet);
      }
  
      /**
       * Execute the task.
       *
       * @throws BuildException if the task fails.
       */
      @Override
      public void execute() throws BuildException {
          validate();
  
          final LibraryDisplayer displayer = new LibraryDisplayer();
          // Check if list of files to check has been specified
          if (libraryFileSets.isEmpty()) {
              displayer.displayLibrary(libraryFile);
          } else {
              for (FileSet fileSet : libraryFileSets) {
                  final DirectoryScanner scanner =
                      fileSet.getDirectoryScanner(getProject());
                  final File basedir = scanner.getBasedir();
                  for (String filename : scanner.getIncludedFiles()) {
                      displayer.displayLibrary(new File(basedir, filename));
                  }
              }
          }
      }
  
      /**
       * Validate the tasks parameters.
       *
       * @throws BuildException if invalid parameters found
       */
      private void validate() throws BuildException {
          if (null == libraryFile) {
              if (libraryFileSets.isEmpty()) {
                  throw new BuildException("File attribute not specified.");
              }
          } else if (!libraryFile.exists()) {
              throw new BuildException("File '%s' does not exist.", libraryFile);
          } else if (!libraryFile.isFile()) {
              throw new BuildException("'%s' is not a file.", libraryFile);
          }
      }
  }
  