commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/url/UrlFileObject.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.url;

import java.io.FileNotFoundException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import org.apache.commons.httpclient.URIException;
import org.apache.commons.vfs2.FileName;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileType;
import org.apache.commons.vfs2.provider.AbstractFileName;
import org.apache.commons.vfs2.provider.AbstractFileObject;
import org.apache.commons.vfs2.provider.URLFileName;

/**
 * A {@link org.apache.commons.vfs2.FileObject FileObject} implementation backed by a {@link URL}.
 * <p>
 * TODO - Implement set lastModified and get/set attribute
 * </p>
 * <p>
 * TODO - Implement getOutputStream().
 * </p>
 */
public class UrlFileObject extends AbstractFileObject<UrlFileSystem> {
    private URL url;

    protected UrlFileObject(final UrlFileSystem fs, final AbstractFileName fileName) {
        super(fileName, fs);
    }

    /**
     * Attaches this file object to its file resource. This method is called before any of the doBlah() or onBlah()
     * methods. Sub-classes can use this method to perform lazy initialization.
     */
    @Override
    protected void doAttach() throws Exception {
        if (url == null) {
            // url = new URL(getName().getURI());
            url = createURL(getName());
        }
    }

    protected URL createURL(final FileName name) throws MalformedURLException, FileSystemException, URIException {
        if (name instanceof URLFileName) {
            final URLFileName urlName = (URLFileName) getName();

            // TODO: charset
            return new URL(urlName.getURIEncoded(null));
        }
        return new URL(getName().getURI());
    }

    /**
     * Determines the type of the file.
     */
    @Override
    protected FileType doGetType() throws Exception {
        try {
            // Attempt to connect & check status
            final URLConnection conn = url.openConnection();
            try (InputStream in = conn.getInputStream()) {
                if (conn instanceof HttpURLConnection) {
                    final int status = ((HttpURLConnection) conn).getResponseCode();
                    // 200 is good, maybe add more later...
                    if (HttpURLConnection.HTTP_OK != status) {
                        return FileType.IMAGINARY;
                    }
                }

                return FileType.FILE;
            }
        } catch (final FileNotFoundException e) {
            return FileType.IMAGINARY;
        }
    }

    /**
     * Returns the size of the file content (in bytes).
     */
    @Override
    protected long doGetContentSize() throws Exception {
        final URLConnection conn = url.openConnection();
        try (InputStream in = conn.getInputStream()) {
            return conn.getContentLength();
        }
    }

    /**
     * Returns the last modified time of this file.
     */
    @Override
    protected long doGetLastModifiedTime() throws Exception {
        final URLConnection conn = url.openConnection();
        try (InputStream in = conn.getInputStream()) {
            return conn.getLastModified();
        }
    }

    /**
     * Lists the children of the file.
     */
    @Override
    protected String[] doListChildren() throws Exception {
        throw new FileSystemException("Not implemented.");
    }

    /**
     * Creates an input stream to read the file content from.
     */
    @Override
    protected InputStream doGetInputStream(final int bufferSize) throws Exception {
        return url.openStream();
    }
}