/*

 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.util.logging;

import java.io.*;

import java.net.*;

/**

 * Simple network logging {@code Handler}.

 * <p>

 * {@code LogRecords} are published to a network stream connection.  By default

 * the {@code XMLFormatter} class is used for formatting.

 * <p>

 * <b>Configuration:</b>

 * By default each {@code SocketHandler} is initialized using the following

 * {@code LogManager} configuration properties where {@code <handler-name>}

 * refers to the fully-qualified class name of the handler.

 * If properties are not defined

 * (or have invalid values) then the specified default values are used.

 * <ul>

 * <li>   &lt;handler-name&gt;.level

 *        specifies the default level for the {@code Handler}

 *        (defaults to {@code Level.ALL}). </li>

 * <li>   &lt;handler-name&gt;.filter

 *        specifies the name of a {@code Filter} class to use

 *        (defaults to no {@code Filter}). </li>

 * <li>   &lt;handler-name&gt;.formatter

 *        specifies the name of a {@code Formatter} class to use

 *        (defaults to {@code java.util.logging.XMLFormatter}). </li>

 * <li>   &lt;handler-name&gt;.encoding

 *        the name of the character set encoding to use (defaults to

 *        the default platform encoding). </li>

 * <li>   &lt;handler-name&gt;.host

 *        specifies the target host name to connect to (no default). </li>

 * <li>   &lt;handler-name&gt;.port

 *        specifies the target TCP port to use (no default). </li>

 * </ul>

 * <p>

 * For example, the properties for {@code SocketHandler} would be:

 * <ul>

 * <li>   java.util.logging.SocketHandler.level=INFO </li>

 * <li>   java.util.logging.SocketHandler.formatter=java.util.logging.SimpleFormatter </li>

 * </ul>

 * <p>

 * For a custom handler, e.g. com.foo.MyHandler, the properties would be:

 * <ul>

 * <li>   com.foo.MyHandler.level=INFO </li>

 * <li>   com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li>

 * </ul>

 * <p>

 * The output IO stream is buffered, but is flushed after each

 * {@code LogRecord} is written.

 *

 * @since 1.4

 */

public class SocketHandler extends StreamHandler {

    private Socket sock;

    private String host;

    private int port;

    /**

     * Create a {@code SocketHandler}, using only {@code LogManager} properties

     * (or their defaults).

     * @throws IllegalArgumentException if the host or port are invalid or

     *          are not specified as LogManager properties.

     * @throws IOException if we are unable to connect to the target

     *         host and port.

     */

    public SocketHandler() throws IOException {

        // configure with specific defaults for SocketHandler

        super(Level.ALL, new XMLFormatter(), null);

        LogManager manager = LogManager.getLogManager();

        String cname = getClass().getName();

        port = manager.getIntProperty(cname + ".port", 0);

        host = manager.getStringProperty(cname + ".host", null);

        try {

            connect();

        } catch (IOException ix) {

            System.err.println("SocketHandler: connect failed to " + host + ":" + port);

            throw ix;

        }

    }

    /**

     * Construct a {@code SocketHandler} using a specified host and port.

     *

     * The {@code SocketHandler} is configured based on {@code LogManager}

     * properties (or their default values) except that the given target host

     * and port arguments are used. If the host argument is empty, but not

     * null String then the localhost is used.

     *

     * @param host target host.

     * @param port target port.

     *

     * @throws IllegalArgumentException if the host or port are invalid.

     * @throws IOException if we are unable to connect to the target

     *         host and port.

     */

    public SocketHandler(String host, int port) throws IOException {

        // configure with specific defaults for SocketHandler

        super(Level.ALL, new XMLFormatter(), null);

        this.port = port;

        this.host = host;

        connect();

    }

    private void connect() throws IOException {

        // Check the arguments are valid.

        if (port == 0) {

            throw new IllegalArgumentException("Bad port: " + port);

        }

        if (host == null) {

            throw new IllegalArgumentException("Null host name: " + host);

        }

        // Try to open a new socket.

        sock = new Socket(host, port);

        OutputStream out = sock.getOutputStream();

        BufferedOutputStream bout = new BufferedOutputStream(out);

        setOutputStreamPrivileged(bout);

    }

    /**

     * Close this output stream.

     *

     * @exception  SecurityException  if a security manager exists and if

     *             the caller does not have {@code LoggingPermission("control")}.

     */

    @Override

    public synchronized void close() throws SecurityException {

        super.close();

        if (sock != null) {

            try {

                sock.close();

            } catch (IOException ix) {

                // drop through.

            }

        }

        sock = null;

    }

    /**

     * Format and publish a {@code LogRecord}.

     *

     * @param  record  description of the log event. A null record is

     *                 silently ignored and is not published

     */

    @Override

    public synchronized void publish(LogRecord record) {

        if (!isLoggable(record)) {

            return;

        }

        super.publish(record);

        flush();

    }

}