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.types.selectors;
  
  import org.apache.tools.ant.BuildException;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.LinkOption;
  import java.nio.file.attribute.GroupPrincipal;
  import java.nio.file.attribute.PosixFileAttributes;
  
  /**
   * A selector that selects files based on their POSIX group.
   *
   * <p>Group is defined in terms of {@link java.nio.file.Files#readAttributes}
   * group attribute as provided by {@link java.nio.file.attribute.PosixFileAttributes},
   * this means the selector will accept any file that exists and has the given
   * group attribute.</p>
   *
   * @since Ant 1.10.4
   */
  public class PosixGroupSelector implements FileSelector {
  
      private String group;
  
      private boolean followSymlinks = true;
  
      /**
       * Sets the group name to look for.
       * @param group the group name
       */
      public void setGroup(String group) {
          this.group = group;
      }
  
      /**
       * Sets the "follow symbolic links" option.
       * @param followSymlinks whether or not symbolic links should be followed.
       */
      public void setFollowSymlinks(boolean followSymlinks) {
          this.followSymlinks = followSymlinks;
      }
  
      @Override
      public boolean isSelected(File basedir, String filename, File file) {
          if (group == null) {
              throw new BuildException("the group attribute is required");
          }
          try {
              GroupPrincipal actualGroup = followSymlinks ? Files.readAttributes(file.toPath(),
                      PosixFileAttributes.class).group() : Files.readAttributes(file.toPath(),
                      PosixFileAttributes.class, LinkOption.NOFOLLOW_LINKS).group();
              return actualGroup != null && actualGroup.getName().equals(group);
          } catch (IOException e) {
              // => not the expected group
          }
          return false;
      }
  }
  