* LogRecords are published to a network stream connection. By default * the XMLFormatter class is used for formatting. *
* Configuration: * By default each SocketHandler is initialized using the following * LogManager configuration properties where <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. *
* For example, the properties for {@code SocketHandler} would be: *
* For a custom handler, e.g. com.foo.MyHandler, the properties would be: *
* The output IO stream is buffered, but is flushed after each * LogRecord is written. * * @since 1.4 */ public class SocketHandler extends StreamHandler { private Socket sock; private String host; private int port; // Private method to configure a SocketHandler from LogManager // properties and/or default values as specified in the class // javadoc. private void configure() { LogManager manager = LogManager.getLogManager(); String cname = getClass().getName(); setLevel(manager.getLevelProperty(cname +".level", Level.ALL)); setFilter(manager.getFilterProperty(cname +".filter", null)); setFormatter(manager.getFormatterProperty(cname +".formatter", new XMLFormatter())); try { setEncoding(manager.getStringProperty(cname +".encoding", null)); } catch (Exception ex) { try { setEncoding(null); } catch (Exception ex2) { // doing a setEncoding with null should always work. // assert false; } } port = manager.getIntProperty(cname + ".port", 0); host = manager.getStringProperty(cname + ".host", null); } /** * Create a SocketHandler, using only 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 { // We are going to use the logging defaults. sealed = false; configure(); try { connect(); } catch (IOException ix) { System.err.println("SocketHandler: connect failed to " + host + ":" + port); throw ix; } sealed = true; } /** * Construct a SocketHandler using a specified host and port. * * The SocketHandler is configured based on 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 { sealed = false; configure(); sealed = true; 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); } if (!NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted()) { throw new IOException("Cleartext traffic not permitted"); } // Try to open a new socket. sock = new Socket(host, port); OutputStream out = sock.getOutputStream(); BufferedOutputStream bout = new BufferedOutputStream(out); setOutputStream(bout); } /** * Close this output stream. * * @exception SecurityException if a security manager exists and if * the caller does not have 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 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(); } }