| /* StreamHandler.java -- |
| A class for publishing log messages to instances of java.io.OutputStream |
| Copyright (C) 2002 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., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 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.OutputStream; |
| import java.io.OutputStreamWriter; |
| import java.io.UnsupportedEncodingException; |
| import java.io.Writer; |
| |
| /** |
| * A <code>StreamHandler</code> publishes <code>LogRecords</code> to |
| * a instances of <code>java.io.OutputStream</code>. |
| * |
| * @author Sascha Brawer (brawer@acm.org) |
| */ |
| public class StreamHandler |
| extends Handler |
| { |
| private OutputStream out; |
| private Writer writer; |
| |
| |
| /** |
| * Indicates the current state of this StreamHandler. The value |
| * should be one of STATE_FRESH, STATE_PUBLISHED, or STATE_CLOSED. |
| */ |
| private int streamState = STATE_FRESH; |
| |
| |
| /** |
| * streamState having this value indicates that the StreamHandler |
| * has been created, but the publish(LogRecord) method has not been |
| * called yet. If the StreamHandler has been constructed without an |
| * OutputStream, writer will be null, otherwise it is set to a |
| * freshly created OutputStreamWriter. |
| */ |
| private static final int STATE_FRESH = 0; |
| |
| |
| /** |
| * streamState having this value indicates that the publish(LocRecord) |
| * method has been called at least once. |
| */ |
| private static final int STATE_PUBLISHED = 1; |
| |
| |
| /** |
| * streamState having this value indicates that the close() method |
| * has been called. |
| */ |
| private static final int STATE_CLOSED = 2; |
| |
| |
| /** |
| * Creates a <code>StreamHandler</code> without an output stream. |
| * Subclasses can later use {@link |
| * #setOutputStream(java.io.OutputStream)} to associate an output |
| * stream with this StreamHandler. |
| */ |
| public StreamHandler() |
| { |
| this(null, null); |
| } |
| |
| |
| /** |
| * Creates a <code>StreamHandler</code> that formats log messages |
| * with the specified Formatter and publishes them to the specified |
| * output stream. |
| * |
| * @param out the output stream to which the formatted log messages |
| * are published. |
| * |
| * @param formatter the <code>Formatter</code> that will be used |
| * to format log messages. |
| */ |
| public StreamHandler(OutputStream out, Formatter formatter) |
| { |
| this(out, "java.util.logging.StreamHandler", Level.INFO, |
| formatter, SimpleFormatter.class); |
| } |
| |
| |
| StreamHandler( |
| OutputStream out, |
| String propertyPrefix, |
| Level defaultLevel, |
| Formatter formatter, Class defaultFormatterClass) |
| { |
| this.level = LogManager.getLevelProperty(propertyPrefix + ".level", |
| defaultLevel); |
| |
| this.filter = (Filter) LogManager.getInstanceProperty( |
| propertyPrefix + ".filter", |
| /* must be instance of */ Filter.class, |
| /* default: new instance of */ null); |
| |
| if (formatter != null) |
| this.formatter = formatter; |
| else |
| this.formatter = (Formatter) LogManager.getInstanceProperty( |
| propertyPrefix + ".formatter", |
| /* must be instance of */ Formatter.class, |
| /* default: new instance of */ defaultFormatterClass); |
| |
| try |
| { |
| String enc = LogManager.getLogManager().getProperty(propertyPrefix |
| + ".encoding"); |
| |
| /* make sure enc actually is a valid encoding */ |
| if ((enc != null) && (enc.length() > 0)) |
| new String(new byte[0], enc); |
| |
| this.encoding = enc; |
| } |
| catch (Exception _) |
| { |
| } |
| |
| if (out != null) |
| { |
| try |
| { |
| changeWriter(out, getEncoding()); |
| } |
| catch (UnsupportedEncodingException uex) |
| { |
| /* This should never happen, since the validity of the encoding |
| * name has been checked above. |
| */ |
| throw new RuntimeException(uex.getMessage()); |
| } |
| } |
| } |
| |
| |
| private void checkOpen() |
| { |
| if (streamState == STATE_CLOSED) |
| throw new IllegalStateException(this.toString() + " has been closed"); |
| } |
| |
| private void checkFresh() |
| { |
| checkOpen(); |
| if (streamState != STATE_FRESH) |
| throw new IllegalStateException("some log records have been published to " + this); |
| } |
| |
| |
| private void changeWriter(OutputStream out, String encoding) |
| throws UnsupportedEncodingException |
| { |
| OutputStreamWriter writer; |
| |
| /* The logging API says that a null encoding means the default |
| * platform encoding. However, java.io.OutputStreamWriter needs |
| * another constructor for the default platform encoding, |
| * passing null would throw an exception. |
| */ |
| if (encoding == null) |
| writer = new OutputStreamWriter(out); |
| else |
| writer = new OutputStreamWriter(out, encoding); |
| |
| /* Closing the stream has side effects -- do this only after |
| * creating a new writer has been successful. |
| */ |
| if ((streamState != STATE_FRESH) || (this.writer != null)) |
| close(); |
| |
| this.writer = writer; |
| this.out = out; |
| this.encoding = encoding; |
| streamState = STATE_FRESH; |
| } |
| |
| |
| /** |
| * Sets the character encoding which this handler uses for publishing |
| * log records. The encoding of a <code>StreamHandler</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. |
| * |
| * @throws SecurityException if a security manager exists and |
| * the caller is not granted the permission to control the |
| * the logging infrastructure. |
| * |
| * @exception IllegalStateException if any log records have been |
| * published to this <code>StreamHandler</code> before. Please |
| * be aware that this is a pecularity of the GNU implementation. |
| * While the API specification indicates that it is an error |
| * if the encoding is set after records have been published, |
| * it does not mandate any specific behavior for that case. |
| */ |
| public void setEncoding(String encoding) |
| throws SecurityException, UnsupportedEncodingException |
| { |
| /* The inherited implementation first checks whether the invoking |
| * code indeed has the permission to control the logging infra- |
| * structure, and throws a SecurityException if this was not the |
| * case. |
| * |
| * Next, it verifies that the encoding is supported and throws |
| * an UnsupportedEncodingExcpetion otherwise. Finally, it remembers |
| * the name of the encoding. |
| */ |
| super.setEncoding(encoding); |
| |
| checkFresh(); |
| |
| /* If out is null, setEncoding is being called before an output |
| * stream has been set. In that case, we need to check that the |
| * encoding is valid, and remember it if this is the case. Since |
| * this is exactly what the inherited implementation of |
| * Handler.setEncoding does, we can delegate. |
| */ |
| if (out != null) |
| { |
| /* The logging API says that a null encoding means the default |
| * platform encoding. However, java.io.OutputStreamWriter needs |
| * another constructor for the default platform encoding, passing |
| * null would throw an exception. |
| */ |
| if (encoding == null) |
| writer = new OutputStreamWriter(out); |
| else |
| writer = new OutputStreamWriter(out, encoding); |
| } |
| } |
| |
| |
| /** |
| * Changes the output stream to which this handler publishes |
| * logging records. |
| * |
| * @throws SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| * |
| * @throws NullPointerException if <code>out</code> |
| * is <code>null</code>. |
| */ |
| protected void setOutputStream(OutputStream out) |
| throws SecurityException |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| /* Throw a NullPointerException if out is null. */ |
| out.getClass(); |
| |
| try |
| { |
| changeWriter(out, getEncoding()); |
| } |
| catch (UnsupportedEncodingException ex) |
| { |
| /* This seems quite unlikely to happen, unless the underlying |
| * implementation of java.io.OutputStreamWriter changes its |
| * mind (at runtime) about the set of supported character |
| * encodings. |
| */ |
| throw new RuntimeException(ex.getMessage()); |
| } |
| } |
| |
| |
| /** |
| * Publishes a <code>LogRecord</code> to the associated output |
| * stream, provided the record passes all tests for being loggable. |
| * The <code>StreamHandler</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. |
| * |
| * <p>If a log record is being published to a |
| * <code>StreamHandler</code> that has been closed earlier, the Sun |
| * J2SE 1.4 reference can be observed to silently ignore the |
| * call. The GNU implementation, however, intentionally behaves |
| * differently by informing the <code>ErrorManager</code> associated |
| * with this <code>StreamHandler</code>. Since the condition |
| * indicates a programming error, the programmer should be |
| * informed. It also seems extremely unlikely that any application |
| * would depend on the exact behavior in this rather obscure, |
| * erroneous case -- especially since the API specification does not |
| * prescribe what is supposed to happen. |
| * |
| * @param record the log event to be published. |
| */ |
| public void publish(LogRecord record) |
| { |
| String formattedMessage; |
| |
| if (!isLoggable(record)) |
| return; |
| |
| if (streamState == STATE_FRESH) |
| { |
| try |
| { |
| writer.write(formatter.getHead(this)); |
| } |
| catch (java.io.IOException ex) |
| { |
| reportError(null, ex, ErrorManager.WRITE_FAILURE); |
| return; |
| } |
| catch (Exception ex) |
| { |
| reportError(null, ex, ErrorManager.GENERIC_FAILURE); |
| return; |
| } |
| |
| streamState = STATE_PUBLISHED; |
| } |
| |
| try |
| { |
| formattedMessage = formatter.format(record); |
| } |
| catch (Exception ex) |
| { |
| reportError(null, ex, ErrorManager.FORMAT_FAILURE); |
| return; |
| } |
| |
| try |
| { |
| writer.write(formattedMessage); |
| } |
| catch (Exception ex) |
| { |
| reportError(null, ex, ErrorManager.WRITE_FAILURE); |
| } |
| } |
| |
| |
| /** |
| * Checks whether or not a <code>LogRecord</code> would be logged |
| * if it was passed to this <code>StreamHandler</code> for publication. |
| * |
| * <p>The <code>StreamHandler</code> implementation first checks |
| * whether a writer is present and the handler's 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>StreamHandler</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) |
| { |
| return (writer != null) && super.isLoggable(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. |
| * |
| * <p>If a <code>StreamHandler</code> that has been closed earlier |
| * is closed a second time, the Sun J2SE 1.4 reference can be |
| * observed to silently ignore the call. The GNU implementation, |
| * however, intentionally behaves differently by informing the |
| * <code>ErrorManager</code> associated with this |
| * <code>StreamHandler</code>. Since the condition indicates a |
| * programming error, the programmer should be informed. It also |
| * seems extremely unlikely that any application would depend on the |
| * exact behavior in this rather obscure, erroneous case -- |
| * especially since the API specification does not prescribe what is |
| * supposed to happen. |
| */ |
| public void flush() |
| { |
| try |
| { |
| checkOpen(); |
| if (writer != null) |
| writer.flush(); |
| } |
| catch (Exception ex) |
| { |
| reportError(null, ex, ErrorManager.FLUSH_FAILURE); |
| } |
| } |
| |
| |
| /** |
| * Closes this <code>StreamHandler</code> after having forced any |
| * data that may have been buffered to the underlying output |
| * device. |
| * |
| * <p>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> |
| * |
| * <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.</p> |
| * |
| * <p>If a <code>StreamHandler</code> that has been closed earlier |
| * is closed a second time, the Sun J2SE 1.4 reference can be |
| * observed to silently ignore the call. The GNU implementation, |
| * however, intentionally behaves differently by informing the |
| * <code>ErrorManager</code> associated with this |
| * <code>StreamHandler</code>. Since the condition indicates a |
| * programming error, the programmer should be informed. It also |
| * seems extremely unlikely that any application would depend on the |
| * exact behavior in this rather obscure, erroneous case -- |
| * especially since the API specification does not prescribe what is |
| * supposed to happen. |
| * |
| * @throws SecurityException if a security manager exists and |
| * the caller is not granted the permission to control |
| * the logging infrastructure. |
| */ |
| public void close() |
| throws SecurityException |
| { |
| LogManager.getLogManager().checkAccess(); |
| |
| try |
| { |
| /* Although flush also calls checkOpen, it catches |
| * any exceptions and reports them to the ErrorManager |
| * as flush failures. However, we want to report |
| * a closed stream as a close failure, not as a |
| * flush failure here. Therefore, we call checkOpen() |
| * before flush(). |
| */ |
| checkOpen(); |
| flush(); |
| |
| if (writer != null) |
| { |
| if (formatter != null) |
| { |
| /* Even if the StreamHandler has never published a record, |
| * it emits head and tail upon closing. An earlier version |
| * of the GNU Classpath implementation did not emitted |
| * anything. However, this had caused XML log files to be |
| * entirely empty instead of containing no log records. |
| */ |
| if (streamState == STATE_FRESH) |
| writer.write(formatter.getHead(this)); |
| if (streamState != STATE_CLOSED) |
| writer.write(formatter.getTail(this)); |
| } |
| streamState = STATE_CLOSED; |
| writer.close(); |
| } |
| } |
| catch (Exception ex) |
| { |
| reportError(null, ex, ErrorManager.CLOSE_FAILURE); |
| } |
| } |
| } |