| /* Handler.java -- a class for publishing log messages |
| Copyright (C) 2002, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.util.logging; |
| |
| import java.io.UnsupportedEncodingException; |
| |
| /** |
| * A <code>Handler</code> publishes <code>LogRecords</code> to |
| * a sink, for example a file, the console or a network socket. |
| * There are different subclasses of <code>Handler</code> |
| * to deal with different kinds of sinks. |
| * |
| * <p>FIXME: Are handlers thread-safe, or is the assumption that only |
| * loggers are, and a handler can belong only to one single logger? If |
| * the latter, should we enforce it? (Spec not clear). In any |
| * case, it needs documentation. |
| * |
| * @author Sascha Brawer (brawer@acm.org) |
| */ |
| public abstract class Handler |
| { |
| Formatter formatter; |
| Filter filter; |
| Level level; |
| ErrorManager errorManager; |
| String encoding; |
| |
| /** |
| * Constructs a Handler with a logging severity level of |
| * <code>Level.ALL</code>, no formatter, no filter, and |
| * an instance of <code>ErrorManager</code> managing errors. |
| * |
| * <p><strong>Specification Note:</strong> The specification of the |
| * Java<sup>TM</sup> Logging API does not mention which character |
| * encoding is to be used by freshly constructed Handlers. The GNU |
| * implementation uses the default platform encoding, but other |
| * Java implementations might behave differently. |
| * |
| * <p><strong>Specification Note:</strong> While a freshly constructed |
| * Handler is required to have <em>no filter</em> according to the |
| * specification, <code>null</code> is not a valid parameter for |
| * <code>Handler.setFormatter</code>. Therefore, the following |
| * code will throw a <code>java.lang.NullPointerException</code>: |
| * |
| * <p><pre>Handler h = new MyConcreteSubclassOfHandler(); |
| h.setFormatter(h.getFormatter());</pre> |
| * |
| * It seems strange that a freshly constructed Handler is not |
| * supposed to provide a Formatter, but this is what the specification |
| * says. |
| */ |
| protected Handler() |
| { |
| level = Level.ALL; |
| } |
| |
| |
| /** |
| * Publishes a <code>LogRecord</code> to an appropriate sink, |
| * provided the record passes all tests for being loggable. The |
| * <code>Handler</code> will localize the message of the log |
| * record and substitute any message parameters. |
| * |
| * <p>Most applications do not need to call this method directly. |
| * Instead, they will use use a {@link Logger}, which will |
| * create LogRecords and distribute them to registered handlers. |
| * |
| * <p>In case of an I/O failure, the <code>ErrorManager</code> |
| * of this <code>Handler</code> will be informed, but the caller |
| * of this method will not receive an exception. |
| * |
| * @param record the log event to be published. |
| */ |
| public abstract void publish(LogRecord record); |
| |
| |
| /** |
| * Forces any data that may have been buffered to the underlying |
| * output device. |
| * |
| * <p>In case of an I/O failure, the <code>ErrorManager</code> |
| * of this <code>Handler</code> will be informed, but the caller |
| * of this method will not receive an exception. |
| */ |
| public abstract void flush(); |
| |
| |
| /** |
| * Closes this <code>Handler</code> after having flushed |
| * the buffers. As soon as <code>close</code> has been called, |
| * a <code>Handler</code> should not be used anymore. Attempts |
| * to publish log records, to flush buffers, or to modify the |
| * <code>Handler</code> in any other way may throw runtime |
| * exceptions after calling <code>close</code>. |
| * |
| * <p>In case of an I/O failure, the <code>ErrorManager</code> |
| * of this <code>Handler</code> will be informed, but the caller |
| * of this method will not receive an exception. |
| * |
| * @throws SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| */ |
| public abstract void close() |
| throws SecurityException; |
| |
| |
| /** |
| * Returns the <code>Formatter</code> which will be used to |
| * localize the text of log messages and to substitute |
| * message parameters. A <code>Handler</code> is encouraged, |
| * but not required to actually use an assigned |
| * <code>Formatter</code>. |
| * |
| * @return the <code>Formatter</code> being used, or |
| * <code>null</code> if this <code>Handler</code> |
| * does not use formatters and no formatter has |
| * ever been set by calling <code>setFormatter</code>. |
| */ |
| public Formatter getFormatter() |
| { |
| return formatter; |
| } |
| |
| |
| /** |
| * Sets the <code>Formatter</code> which will be used to |
| * localize the text of log messages and to substitute |
| * message parameters. A <code>Handler</code> is encouraged, |
| * but not required to actually use an assigned |
| * <code>Formatter</code>. |
| * |
| * @param formatter the new <code>Formatter</code> to use. |
| * |
| * @throws SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| * |
| * @throws NullPointerException if <code>formatter</code> is |
| * <code>null</code>. |
| */ |
| public void setFormatter(Formatter formatter) |
| throws SecurityException |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Throws a NullPointerException if formatter is null. */ |
| formatter.getClass(); |
| |
| this.formatter = formatter; |
| } |
| |
| |
| /** |
| * Returns the character encoding which this handler uses for publishing |
| * log records. |
| * |
| * @return the name of a character encoding, or <code>null</code> |
| * for the default platform encoding. |
| */ |
| public String getEncoding() |
| { |
| return encoding; |
| } |
| |
| |
| /** |
| * Sets the character encoding which this handler uses for publishing |
| * log records. The encoding of a <code>Handler</code> must be |
| * set before any log records have been published. |
| * |
| * @param encoding the name of a character encoding, or <code>null</code> |
| * for the default encoding. |
| * |
| * @exception SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| * |
| */ |
| public void setEncoding(String encoding) |
| throws SecurityException, UnsupportedEncodingException |
| { |
| /* Should any developer ever change this implementation, they are |
| * advised to have a look at StreamHandler.setEncoding(String), |
| * which overrides this method without calling super.setEncoding. |
| */ |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Simple check for supported encodings. This is more expensive |
| * than it could be, but this method is overwritten by StreamHandler |
| * anyway. |
| */ |
| if (encoding != null) |
| new String(new byte[0], encoding); |
| |
| this.encoding = encoding; |
| } |
| |
| |
| /** |
| * Returns the <code>Filter</code> that currently controls which |
| * log records are being published by this <code>Handler</code>. |
| * |
| * @return the currently active <code>Filter</code>, or |
| * <code>null</code> if no filter has been associated. |
| * In the latter case, log records are filtered purely |
| * based on their severity level. |
| */ |
| public Filter getFilter() |
| { |
| return filter; |
| } |
| |
| |
| /** |
| * Sets the <code>Filter</code> for controlling which |
| * log records will be published by this <code>Handler</code>. |
| * |
| * @param filter the <code>Filter</code> to use, or |
| * <code>null</code> to filter log records purely based |
| * on their severity level. |
| */ |
| public void setFilter(Filter filter) |
| throws SecurityException |
| { |
| LogManager.getLogManager().checkAccess(); |
| this.filter = filter; |
| } |
| |
| |
| /** |
| * Returns the <code>ErrorManager</code> that currently deals |
| * with errors originating from this Handler. |
| * |
| * @exception SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| */ |
| public ErrorManager getErrorManager() |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Developers wanting to change the subsequent code should |
| * have a look at Handler.reportError -- it also can create |
| * an ErrorManager, but does so without checking permissions |
| * to control the logging infrastructure. |
| */ |
| if (errorManager == null) |
| errorManager = new ErrorManager(); |
| |
| return errorManager; |
| } |
| |
| |
| public void setErrorManager(ErrorManager manager) |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Make sure manager is not null. */ |
| manager.getClass(); |
| |
| this.errorManager = manager; |
| } |
| |
| |
| protected void reportError(String message, Exception ex, int code) |
| { |
| if (errorManager == null) |
| errorManager = new ErrorManager(); |
| |
| errorManager.error(message, ex, code); |
| } |
| |
| |
| /** |
| * Returns the severity level threshold for this <code>Handler</code> |
| * All log records with a lower severity level will be discarded; |
| * a log record of the same or a higher level will be published |
| * unless an installed <code>Filter</code> decides to discard it. |
| * |
| * @return the severity level below which all log messages |
| * will be discarded. |
| */ |
| public Level getLevel() |
| { |
| return level; |
| } |
| |
| |
| /** |
| * Sets the severity level threshold for this <code>Handler</code>. |
| * All log records with a lower severity level will be discarded; |
| * a log record of the same or a higher level will be published |
| * unless an installed <code>Filter</code> decides to discard it. |
| * |
| * @param level the severity level below which all log messages |
| * will be discarded. |
| * |
| * @exception SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| * |
| * @exception NullPointerException if <code>level</code> is |
| * <code>null</code>. |
| */ |
| public void setLevel(Level level) |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Throw NullPointerException if level is null. */ |
| level.getClass(); |
| this.level = level; |
| } |
| |
| |
| /** |
| * Checks whether a <code>LogRecord</code> would be logged |
| * if it was passed to this <code>Handler</code> for publication. |
| * |
| * <p>The <code>Handler</code> implementation considers a record as |
| * loggable if its level is greater than or equal to the severity |
| * level threshold. In a second step, if a {@link Filter} has |
| * been installed, its {@link Filter#isLoggable(LogRecord) isLoggable} |
| * method is invoked. Subclasses of <code>Handler</code> can override |
| * this method to impose their own constraints. |
| * |
| * @param record the <code>LogRecord</code> to be checked. |
| * |
| * @return <code>true</code> if <code>record</code> would |
| * be published by {@link #publish(LogRecord) publish}, |
| * <code>false</code> if it would be discarded. |
| * |
| * @see #setLevel(Level) |
| * @see #setFilter(Filter) |
| * @see Filter#isLoggable(LogRecord) |
| * |
| * @throws NullPointerException if <code>record</code> |
| * is <code>null</code>. |
| */ |
| public boolean isLoggable(LogRecord record) |
| { |
| if (record.getLevel().intValue() < level.intValue()) |
| return false; |
| |
| if (filter != null) |
| return filter.isLoggable(record); |
| else |
| return true; |
| } |
| } |