001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.vfs2.provider;
018    
019    import org.apache.commons.vfs2.FileObject;
020    import org.apache.commons.vfs2.FileSystemException;
021    import org.apache.commons.vfs2.FileSystemOptions;
022    
023    /**
024     * Description.
025     *
026     * @author <a href="http://commons.apache.org/vfs/team-list.html">Commons VFS team</a>
027     */
028    public abstract class CompositeFileProvider extends AbstractFileProvider
029    {
030        private static final int INITIAL_BUFSZ = 80;
031    
032        public CompositeFileProvider()
033        {
034            super();
035        }
036    
037        /**
038         * The schemes to use for resolve
039         */
040        protected abstract String[] getSchemes();
041    
042        /**
043         * Locates a file object, by absolute URI.
044         * @param baseFile The base FileObject.
045         * @param uri The file to find.
046         * @param fileSystemOptions The options for the FileSystem.
047         * @return A FileObject for the located file.
048         * @throws FileSystemException if an error occurs.
049         */
050        public FileObject findFile(final FileObject baseFile,
051                                   final String uri,
052                                   final FileSystemOptions fileSystemOptions)
053            throws FileSystemException
054        {
055            StringBuilder buf = new StringBuilder(INITIAL_BUFSZ);
056    
057            UriParser.extractScheme(uri, buf);
058    
059            String[] schemes = getSchemes();
060            for (int iterSchemes = 0; iterSchemes < schemes.length; iterSchemes++)
061            {
062                buf.insert(0, ":");
063                buf.insert(0, schemes[iterSchemes]);
064            }
065    
066            FileObject fo = getContext().getFileSystemManager().resolveFile(buf.toString(), fileSystemOptions);
067            return fo;
068        }
069    }