| /* |
| * Copyright (c) 2000, 2019, 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.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.Objects; |
| |
| /** |
| * Stream based logging {@code Handler}. |
| * <p> |
| * This is primarily intended as a base class or support class to |
| * be used in implementing other logging {@code Handlers}. |
| * <p> |
| * {@code LogRecords} are published to a given {@code java.io.OutputStream}. |
| * <p> |
| * <b>Configuration:</b> |
| * By default each {@code StreamHandler} 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> <handler-name>.level |
| * specifies the default level for the {@code Handler} |
| * (defaults to {@code Level.INFO}). </li> |
| * <li> <handler-name>.filter |
| * specifies the name of a {@code Filter} class to use |
| * (defaults to no {@code Filter}). </li> |
| * <li> <handler-name>.formatter |
| * specifies the name of a {@code Formatter} class to use |
| * (defaults to {@code java.util.logging.SimpleFormatter}). </li> |
| * <li> <handler-name>.encoding |
| * the name of the character set encoding to use (defaults to |
| * the default platform encoding). </li> |
| * </ul> |
| * <p> |
| * For example, the properties for {@code StreamHandler} would be: |
| * <ul> |
| * <li> java.util.logging.StreamHandler.level=INFO </li> |
| * <li> java.util.logging.StreamHandler.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> |
| * |
| * @since 1.4 |
| */ |
| |
| public class StreamHandler extends Handler { |
| private OutputStream output; |
| private boolean doneHeader; |
| private volatile Writer writer; |
| |
| /** |
| * Create a {@code StreamHandler}, with no current output stream. |
| */ |
| public StreamHandler() { |
| // configure with specific defaults for StreamHandler |
| super(Level.INFO, new SimpleFormatter(), null); |
| } |
| |
| /** |
| * Create a {@code StreamHandler} with a given {@code Formatter} |
| * and output stream. |
| * |
| * @param out the target output stream |
| * @param formatter Formatter to be used to format output |
| */ |
| public StreamHandler(OutputStream out, Formatter formatter) { |
| // configure with default level but use specified formatter |
| super(Level.INFO, null, Objects.requireNonNull(formatter)); |
| |
| setOutputStreamPrivileged(out); |
| } |
| |
| /** |
| * @see Handler#Handler(Level, Formatter, Formatter) |
| */ |
| StreamHandler(Level defaultLevel, |
| Formatter defaultFormatter, |
| Formatter specifiedFormatter) { |
| super(defaultLevel, defaultFormatter, specifiedFormatter); |
| } |
| |
| /** |
| * Change the output stream. |
| * <P> |
| * If there is a current output stream then the {@code Formatter}'s |
| * tail string is written and the stream is flushed and closed. |
| * Then the output stream is replaced with the new output stream. |
| * |
| * @param out New output stream. May not be null. |
| * @exception SecurityException if a security manager exists and if |
| * the caller does not have {@code LoggingPermission("control")}. |
| */ |
| protected synchronized void setOutputStream(OutputStream out) throws SecurityException { |
| if (out == null) { |
| throw new NullPointerException(); |
| } |
| flushAndClose(); |
| output = out; |
| doneHeader = false; |
| String encoding = getEncoding(); |
| if (encoding == null) { |
| writer = new OutputStreamWriter(output); |
| } else { |
| try { |
| writer = new OutputStreamWriter(output, encoding); |
| } catch (UnsupportedEncodingException ex) { |
| // This shouldn't happen. The setEncoding method |
| // should have validated that the encoding is OK. |
| throw new Error("Unexpected exception " + ex); |
| } |
| } |
| } |
| |
| /** |
| * Set (or change) the character encoding used by this {@code Handler}. |
| * <p> |
| * The encoding should be set before any {@code LogRecords} are written |
| * to the {@code Handler}. |
| * |
| * @param encoding The name of a supported character encoding. |
| * May be null, to indicate the default platform encoding. |
| * @exception SecurityException if a security manager exists and if |
| * the caller does not have {@code LoggingPermission("control")}. |
| * @exception UnsupportedEncodingException if the named encoding is |
| * not supported. |
| */ |
| @Override |
| public synchronized void setEncoding(String encoding) |
| throws SecurityException, java.io.UnsupportedEncodingException { |
| super.setEncoding(encoding); |
| if (output == null) { |
| return; |
| } |
| // Replace the current writer with a writer for the new encoding. |
| flush(); |
| if (encoding == null) { |
| writer = new OutputStreamWriter(output); |
| } else { |
| writer = new OutputStreamWriter(output, encoding); |
| } |
| } |
| |
| /** |
| * Format and publish a {@code LogRecord}. |
| * <p> |
| * The {@code StreamHandler} first checks if there is an {@code OutputStream} |
| * and if the given {@code LogRecord} has at least the required log level. |
| * If not it silently returns. If so, it calls any associated |
| * {@code Filter} to check if the record should be published. If so, |
| * it calls its {@code Formatter} to format the record and then writes |
| * the result to the current output stream. |
| * <p> |
| * If this is the first {@code LogRecord} to be written to a given |
| * {@code OutputStream}, the {@code Formatter}'s "head" string is |
| * written to the stream before the {@code LogRecord} is written. |
| * |
| * @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; |
| } |
| String msg; |
| try { |
| msg = getFormatter().format(record); |
| } catch (Exception ex) { |
| // We don't want to throw an exception here, but we |
| // report the exception to any registered ErrorManager. |
| reportError(null, ex, ErrorManager.FORMAT_FAILURE); |
| return; |
| } |
| |
| try { |
| if (!doneHeader) { |
| writer.write(getFormatter().getHead(this)); |
| doneHeader = true; |
| } |
| writer.write(msg); |
| } catch (Exception ex) { |
| // We don't want to throw an exception here, but we |
| // report the exception to any registered ErrorManager. |
| reportError(null, ex, ErrorManager.WRITE_FAILURE); |
| } |
| } |
| |
| |
| /** |
| * Check if this {@code Handler} would actually log a given {@code LogRecord}. |
| * <p> |
| * This method checks if the {@code LogRecord} has an appropriate level and |
| * whether it satisfies any {@code Filter}. It will also return false if |
| * no output stream has been assigned yet or the LogRecord is null. |
| * |
| * @param record a {@code LogRecord} (may be null). |
| * @return true if the {@code LogRecord} would be logged. |
| * |
| */ |
| @Override |
| public boolean isLoggable(LogRecord record) { |
| if (writer == null || record == null) { |
| return false; |
| } |
| return super.isLoggable(record); |
| } |
| |
| /** |
| * Flush any buffered messages. |
| */ |
| @Override |
| public synchronized void flush() { |
| if (writer != null) { |
| try { |
| writer.flush(); |
| } catch (Exception ex) { |
| // We don't want to throw an exception here, but we |
| // report the exception to any registered ErrorManager. |
| reportError(null, ex, ErrorManager.FLUSH_FAILURE); |
| } |
| } |
| } |
| |
| private synchronized void flushAndClose() throws SecurityException { |
| checkPermission(); |
| if (writer != null) { |
| try { |
| if (!doneHeader) { |
| writer.write(getFormatter().getHead(this)); |
| doneHeader = true; |
| } |
| writer.write(getFormatter().getTail(this)); |
| writer.flush(); |
| writer.close(); |
| } catch (Exception ex) { |
| // We don't want to throw an exception here, but we |
| // report the exception to any registered ErrorManager. |
| reportError(null, ex, ErrorManager.CLOSE_FAILURE); |
| } |
| writer = null; |
| output = null; |
| } |
| } |
| |
| /** |
| * Close the current output stream. |
| * <p> |
| * The {@code Formatter}'s "tail" string is written to the stream before it |
| * is closed. In addition, if the {@code Formatter}'s "head" string has not |
| * yet been written to the stream, it will be written before the |
| * "tail" string. |
| * |
| * @exception SecurityException if a security manager exists and if |
| * the caller does not have LoggingPermission("control"). |
| */ |
| @Override |
| public synchronized void close() throws SecurityException { |
| flushAndClose(); |
| } |
| |
| // Package-private support for setting OutputStream |
| // with elevated privilege. |
| final void setOutputStreamPrivileged(final OutputStream out) { |
| AccessController.doPrivileged(new PrivilegedAction<Void>() { |
| @Override |
| public Void run() { |
| setOutputStream(out); |
| return null; |
| } |
| }, null, LogManager.controlPermission); |
| } |
| } |
