commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/res/ResourceFileProvider.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.res;

import java.net.URL;
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.FileSystemConfigBuilder;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileSystemOptions;
import org.apache.commons.vfs2.provider.AbstractFileProvider;

/**
 * The Resource provider.
 */
public class ResourceFileProvider extends AbstractFileProvider {

    /** The provider's capabilities */
    protected static final Collection<Capability> capabilities = Collections
            .unmodifiableCollection(Arrays.asList(Capability.DISPATCHER));

    private static final int BUFFER_SIZE = 80;

    public ResourceFileProvider() {
        setFileNameParser(ResourceFileNameParser.getInstance());
    }

    /**
     * Locates a file object, by absolute URI.
     *
     * @param baseFile The base file.
     * @param uri The URI of the file to locate.
     * @param fileSystemOptions The FileSystem options.
     * @return the FileObject.
     * @throws FileSystemException if an error occurs.
     */
    @Override
    public FileObject findFile(final FileObject baseFile, final String uri, final FileSystemOptions fileSystemOptions)
            throws FileSystemException {
        final FileName fileName;
        if (baseFile != null) {
            fileName = parseUri(baseFile.getName(), uri);
        }
        else {
            fileName = parseUri(null, uri);
        }
        final String resourceName = fileName.getPath();

        ClassLoader classLoader = ResourceFileSystemConfigBuilder.getInstance().getClassLoader(fileSystemOptions);
        if (classLoader == null) {
            classLoader = getClass().getClassLoader();
        }
        FileSystemException.requireNonNull(classLoader, "vfs.provider.url/badly-formed-uri.error", uri);
        final URL url = classLoader.getResource(resourceName);

        FileSystemException.requireNonNull(url, "vfs.provider.url/badly-formed-uri.error", uri);

        return getContext().getFileSystemManager().resolveFile(url.toExternalForm());
    }

    @Override
    public FileSystemConfigBuilder getConfigBuilder() {
        return org.apache.commons.vfs2.provider.res.ResourceFileSystemConfigBuilder.getInstance();
    }

    @Override
    public void closeFileSystem(final FileSystem filesystem) {
        // no filesystem created here - so nothing to do
    }

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