src/java/org/apache/commons/vfs/provider/jar/JarFileProvider.java

/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * Licensed 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.vfs.provider.jar;

import org.apache.commons.vfs.Capability;
import org.apache.commons.vfs.FileName;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSystem;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemOptions;
import org.apache.commons.vfs.provider.LayeredFileName;
import org.apache.commons.vfs.provider.zip.ZipFileProvider;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;

/**
 * A file system provider for Jar files.  Provides read-only file
 * systems.  This provides access to Jar specific features like Signing and
 * Manifest Attributes.
 *
 * @author <a href="mailto:brian@mmmanager.org">Brian Olsen</a>
 * @version $Revision$ $Date$
 */
public class JarFileProvider
    extends ZipFileProvider
{
    final static Collection capabilities;

    static
    {
        Collection combined = new ArrayList();
        combined.addAll(ZipFileProvider.capabilities);
        combined.addAll(Arrays.asList(new Capability[]
        {
            Capability.ATTRIBUTES,
            Capability.FS_ATTRIBUTES,
            Capability.SIGNING,
            Capability.MANIFEST_ATTRIBUTES,
            Capability.VIRTUAL
        }));
        capabilities = Collections.unmodifiableCollection(combined);
    }

    public JarFileProvider()
    {
        super();
    }

    /**
     * Creates a layered file system.  This method is called if the file system
     * is not cached.
     *
     * @param scheme The URI scheme.
     * @param file   The file to create the file system on top of.
     * @return The file system.
     */
    protected FileSystem doCreateFileSystem(final String scheme,
                                            final FileObject file,
                                            final FileSystemOptions fileSystemOptions)
        throws FileSystemException
    {
        final FileName name =
            new LayeredFileName(scheme, file.getName(), FileName.ROOT_PATH);
        return new JarFileSystem(name, file, fileSystemOptions);
    }

    public Collection getCapabilities()
    {
        return capabilities;
    }
}