/*
    * 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.commons.vfs2.provider.jar;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Collection;
  import java.util.jar.Attributes;
  import java.util.jar.Attributes.Name;
  import java.util.jar.JarFile;
  import java.util.jar.Manifest;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipFile;
  
  import org.apache.commons.vfs2.Capability;
  import org.apache.commons.vfs2.FileObject;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.FileSystemOptions;
  import org.apache.commons.vfs2.provider.AbstractFileName;
  import org.apache.commons.vfs2.provider.zip.ZipFileObject;
  import org.apache.commons.vfs2.provider.zip.ZipFileSystem;
  
  /**
   * A read-only file system for Jar files.
   */
  public class JarFileSystem extends ZipFileSystem {
      private Attributes attributes;
  
      /**
       * Constructs a new instance.
       *
       * @param rootFileName The root file name of this file system.
       * @param parentLayer The parent layer of this file system.
       * @param fileSystemOptions Options to build this file system.
       * @throws FileSystemException If the parent layer does not exist, or on error replicating the file.
       */
      protected JarFileSystem(final AbstractFileName rootFileName, final FileObject parentLayer, final FileSystemOptions fileSystemOptions)
              throws FileSystemException {
          super(rootFileName, parentLayer, fileSystemOptions);
      }
  
      // @Override
      // protected FileObject createFile(AbstractFileName name) throws FileSystemException
      // {
      // return new JarFileObject(name, null, this, false);
      // }
  
      /**
       * Returns the capabilities of this file system.
       */
      @Override
      protected void addCapabilities(final Collection<Capability> caps) {
          // super.addCapabilities(caps);
          caps.addAll(JarFileProvider.CAPABILITIES);
      }
  
      @Override
      protected ZipFile createZipFile(final File file) throws FileSystemException {
          try {
              return new JarFile(file);
          } catch (final IOException ioe) {
              throw new FileSystemException("vfs.provider.jar/open-jar-file.error", file, ioe);
          }
      }
  
      @Override
      protected ZipFileObject createZipFileObject(final AbstractFileName name, final ZipEntry entry)
              throws FileSystemException {
          return new JarFileObject(name, entry, this, true);
      }
  
      Object getAttribute(final Name attrName) throws FileSystemException {
          try {
              final Attributes attr = getAttributes();
              return attr.getValue(attrName);
          } catch (final IOException ioe) {
              throw new FileSystemException(attrName.toString(), ioe);
          }
      }
  
      /**
       * Retrieves the attribute with the specified name. The default implementation simply throws an exception.
       *
       * @param attrName The attribute's name.
       * @return The value of the attribute.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public Object getAttribute(final String attrName) throws FileSystemException {
         final Name name = lookupName(attrName);
         return getAttribute(name);
     }
 
     Attributes getAttributes() throws IOException {
         if (attributes == null) {
             final Manifest man = ((JarFile) getZipFile()).getManifest();
             if (man == null) {
                 attributes = new Attributes(1);
             } else {
                 attributes = man.getMainAttributes();
                 if (attributes == null) {
                     attributes = new Attributes(1);
                 }
             }
         }
 
         return attributes;
     }
 
     @Override
     protected ZipFile getZipFile() throws FileSystemException {
         // make accessible
         return super.getZipFile();
     }
 
     Name lookupName(final String attrName) {
         if (Name.CLASS_PATH.toString().equals(attrName)) {
             return Name.CLASS_PATH;
         }
         if (Name.CONTENT_TYPE.toString().equals(attrName)) {
             return Name.CONTENT_TYPE;
         }
         if (Name.EXTENSION_INSTALLATION.toString().equals(attrName)) {
             return Name.EXTENSION_INSTALLATION;
         }
         if (Name.EXTENSION_LIST.toString().equals(attrName)) {
             return Name.EXTENSION_LIST;
         }
         if (Name.EXTENSION_NAME.toString().equals(attrName)) {
             return Name.EXTENSION_NAME;
         }
         if (Name.IMPLEMENTATION_TITLE.toString().equals(attrName)) {
             return Name.IMPLEMENTATION_TITLE;
         }
         if (Name.IMPLEMENTATION_URL.toString().equals(attrName)) {
             return Name.IMPLEMENTATION_URL;
         }
         if (Name.IMPLEMENTATION_VENDOR.toString().equals(attrName)) {
             return Name.IMPLEMENTATION_VENDOR;
         }
         if (Name.IMPLEMENTATION_VENDOR_ID.toString().equals(attrName)) {
             return Name.IMPLEMENTATION_VENDOR_ID;
         }
         if (Name.IMPLEMENTATION_VERSION.toString().equals(attrName)) {
             return Name.IMPLEMENTATION_VENDOR;
         }
         if (Name.MAIN_CLASS.toString().equals(attrName)) {
             return Name.MAIN_CLASS;
         }
         if (Name.MANIFEST_VERSION.toString().equals(attrName)) {
             return Name.MANIFEST_VERSION;
         }
         if (Name.SEALED.toString().equals(attrName)) {
             return Name.SEALED;
         }
         if (Name.SIGNATURE_VERSION.toString().equals(attrName)) {
             return Name.SIGNATURE_VERSION;
         }
         if (Name.SPECIFICATION_TITLE.toString().equals(attrName)) {
             return Name.SPECIFICATION_TITLE;
         }
         if (Name.SPECIFICATION_VENDOR.toString().equals(attrName)) {
             return Name.SPECIFICATION_VENDOR;
         }
         if (Name.SPECIFICATION_VERSION.toString().equals(attrName)) {
             return Name.SPECIFICATION_VERSION;
         }
         return new Name(attrName);
     }
 
 }