trunk/core/src/main/java/org/apache/commons/vfs2/provider/tar/TarFileProvider.java

/*
 * 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.tar;

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

import org.apache.commons.vfs2.Capability;
import org.apache.commons.vfs2.FileName;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystem;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileSystemOptions;
import org.apache.commons.vfs2.FileType;
import org.apache.commons.vfs2.provider.AbstractFileName;
import org.apache.commons.vfs2.provider.AbstractLayeredFileProvider;
import org.apache.commons.vfs2.provider.FileProvider;
import org.apache.commons.vfs2.provider.LayeredFileName;

/**
 * A file system provider for Tar files.  Provides read-only file systems.
 */
public class TarFileProvider extends AbstractLayeredFileProvider implements FileProvider
{
    /** The provider's capabilities */
    protected static final Collection<Capability> capabilities =
        Collections.unmodifiableCollection(Arrays.asList(new Capability[]
        {
            Capability.GET_LAST_MODIFIED,
            Capability.GET_TYPE,
            Capability.LIST_CHILDREN,
            Capability.READ_CONTENT,
            Capability.URI,
            Capability.VIRTUAL
        }));

    public TarFileProvider()
    {
        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.
     */
    @Override
    protected FileSystem doCreateFileSystem(final String scheme,
                                            final FileObject file,
                                            final FileSystemOptions fileSystemOptions)
        throws FileSystemException
    {
        final AbstractFileName rootName =
            new LayeredFileName(scheme, file.getName(), FileName.ROOT_PATH, FileType.FOLDER);
        return new TarFileSystem(rootName, file, fileSystemOptions);
    }

    @Override
    public Collection<Capability> getCapabilities()
    {
        return capabilities;
    }
}