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The Pax Logging API Library is to allow for the Pax Logging Service to be reloaded without stopping the many
dependent bundles. It also contains the OSGi Log Service API and the Knopflerfish Log API.
/*
* Copyright (c) 2003, KNOPFLERFISH project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* - Neither the name of the KNOPFLERFISH project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.knopflerfish.service.log;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.osgi.framework.BundleContext;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceEvent;
import org.osgi.framework.ServiceListener;
import org.osgi.framework.ServiceReference;
/**
* * LogRef is an utility class that simplifies the use of the LogService. * *
* * * LogRef let you use the log without worrying about getting new *
* service objects when the log service is restarted. It also * supplies methods
* with short names that does logging with all the * different LogService
* severity types. * *
*
* * * To use the LogRef you need to import *
* org.knopflerfish.service.log.LogRef and instantiate * LogRef
* with your bundle context as parameter. The bundle context * is used for
* getting the LogService and adding a service listener. * *
*
* *
* Example usage
* * The if statement that protects
* each call to the * LogRef instance below is there to save the
* effort * required for creating the message string object in cases where the *
* log will throw away the log entry due to its unimportance. The * user must
* have this if-test in his code since that is * the only way to
* avoid constructing the string object. Placing it * in the wrapper (LogRef)
* will not help due to the design of the Java * programming language. * * *
*
* * package org.knopflerfish.example.hello; * * import
* org.osgi.framework.*; * import org.knopflerfish.service.log.LogRef; * * *
* public class Hello implements BundleActivator { * LogRef log; * * public void
* start(BundleContext bundleContext) { * log = new LogRef(bundleContext); * if
* (log.doInfo()) log.info("Hello started."); * } * * public void
* stop(BundleContext bundleContext) { * if (log.doDebug()) log.debug("Hello
* stopped."); * } * } *
*
* * * *
*
* @author Gatespace AB *
* @see org.osgi.service.log.LogService *
* @see org.knopflerfish.service.log.LogService
*/
public class LogRef implements ServiceListener, LogService {
// Class name of the OSGI log service
private final static String LOG_CLASS_OSGI = org.osgi.service.log.LogService.class
.getName();
// Class name of Knopflerfish extended log service
private final static String LOG_CLASS_KF = org.knopflerfish.service.log.LogService.class
.getName();
private final static String logServiceFilter = "(|" + "(objectClass="
+ LOG_CLASS_KF + ")(objectClass=" + LOG_CLASS_OSGI + "))";
// Date formater used then sending entries to System.out
private static SimpleDateFormat simpleDateFormat = null;
// Handle to the framework
private BundleContext bc;
// Service reference for the current log service
private ServiceReference logSR;
// The current log service
private org.osgi.service.log.LogService log;
// If true and no log service, print on System.out
private boolean useOut;
// The id of the calling bundle
private long bundleId;
// If true warn about using closed LogRef object
private boolean doWarnIfClosed;
/**
* * Create new LogRef object for a given bundle. *
*
* @param bc
* the bundle context of the bundle that this log ref * instance
* belongs too. *
* @param out
* If true print messages on System.out when *
* there is no log service.
*/
public LogRef(BundleContext bc, boolean out) {
init(bc, out);
}
/**
* * Create new LogRef object for a given bundle. * *
* * If the system property org.knopflerfish.log.out equals *
* "true", system.out will be used as fallback if no log service * is found. *
*
*
*
* @param bc
* the bundle context of the bundle that this log ref * instance
* belongs too.
*/
public LogRef(BundleContext bc) {
boolean b = false;
try {
b = "true".equals(System.getProperty("org.knopflerfish.log.out"));
} catch (Throwable t) {
System.err.println("get system property failed: " + t);
t.printStackTrace();
}
init(bc, b);
}
private void init(BundleContext bc, boolean out) {
this.bc = bc;
useOut = out;
bundleId = bc.getBundle().getBundleId();
try {
bc.addServiceListener(this, logServiceFilter);
} catch (InvalidSyntaxException e) {
error("Failed to register log service listener (filter="
+ logServiceFilter + ")", e);
}
}
/**
* * Service listener entry point. Releases the log service object if * one
* has been fetched. * *
*
* @param evt
* Service event
*/
public void serviceChanged(ServiceEvent evt) {
if (evt.getServiceReference() == logSR
&& evt.getType() == ServiceEvent.UNREGISTERING) {
ungetLogService();
}
}
/**
* * Unget the log service. Note that this method is synchronized on * the
* same object as the internal method that calls the actual log * service.
* This ensures that the log service is not removed by * this method while a
* log message is generated.
*/
private synchronized void ungetLogService() {
doWarnIfClosed = doDebug();
if (log != null) {
bc.ungetService(logSR);
logSR = null;
log = null;
}
}
/**
* * Close this LogRef object. Ungets the log service if active.
*/
public void close() {
ungetLogService();
bc.removeServiceListener(this);
bc = null;
}
/**
* * Sends a message to the log if possible. * *
*
* @param msg
* Human readable string describing the condition. *
* @param level
* The severity of the message (Should be one of the * four
* predefined severities). *
* @param sr
* The ServiceReference of the service * that this
* message is associated with. *
* @param e
* The exception that reflects the condition.
*/
protected synchronized void doLog(String msg, int level,
ServiceReference sr, Throwable e) {
if (bc != null && log == null) {
logSR = bc.getServiceReference(LOG_CLASS_KF);
if (logSR == null) {
// No service implementing the Knopflerfish extended log, try to
// look for a standard OSGi log service.
logSR = bc.getServiceReference(LOG_CLASS_OSGI);
}
if (logSR != null) {
log = (org.osgi.service.log.LogService) bc.getService(logSR);
}
if (log == null) {
// Failed to get log service clear the service reference.
logSR = null;
}
}
if (log != null) {
log.log(sr, level, msg, e);
} else if (useOut || doWarnIfClosed) {
if (bc == null) {
System.err.println("WARNING! Bundle #" + bundleId
+ " called closed LogRef object");
}
// No log service and request for messages on System.out
System.out.print(LogUtil.fromLevel(level, 8));
System.out.print(" ");
if (simpleDateFormat == null) {
simpleDateFormat = new SimpleDateFormat("yyyyMMdd HH:mm:ss");
}
System.out.print(simpleDateFormat.format(new Date()));
System.out.print(" ");
System.out.print(getBundleName());
System.out.print(" - ");
if (sr != null) {
System.out.print("[");
System.out.print(sr);
System.out.print("] ");
}
System.out.print(msg);
if (e != null) {
System.out.print(" (");
System.out.print(e);
System.out.print(")");
System.out.println();
e.printStackTrace();
}
System.out.println();
}
}
/**
* * Returns the current log level. There is no use to generate log *
* entries with a severity level less than this value since such * entries
* will be thrown away by the log. * *
*
* @return the current severity log level for this bundle.
*/
public int getLogLevel() {
if (log != null && (log instanceof LogService)) {
return ((LogService) log).getLogLevel();
}
return LOG_DEBUG;
}
/**
* * Returns true if messages with severity debug or higher * are saved by
* the log. *
*
* @return true if messages with severity LOG_DEBUG * or
* higher are included in the log, otherwise false.
*/
public boolean doDebug() {
return getLogLevel() >= LOG_DEBUG;
}
/**
* * Returns true if messages with severity warning or higher * are saved by
* the log. *
*
* @return true if messages with severity LOG_WARNING * or
* higher are included in the log, otherwise false.
*/
public boolean doWarn() {
return getLogLevel() >= LOG_WARNING;
}
/**
* * Returns true if messages with severity info or higher * are saved by
* the log. *
*
* @return true if messages with severity LOG_INFO * or
* higher are included in the log, otherwise false.
*/
public boolean doInfo() {
return getLogLevel() >= LOG_INFO;
}
/**
* * Returns true if messages with severity error or higher * are saved by
* the log. *
*
* @return true if messages with severity LOG_ERROR * or
* higher are included in the log, otherwise false.
*/
public boolean doError() {
return getLogLevel() >= LOG_ERROR;
}
/**
* * Log a debug level message * *
*
* @param msg
* Log message.
*/
public void debug(String msg) {
doLog(msg, LOG_DEBUG, null, null);
}
/**
* * Log a debug level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with.
*/
public void debug(String msg, ServiceReference sr) {
doLog(msg, LOG_DEBUG, sr, null);
}
/**
* * Log a debug level message. * *
*
* @param msg
* Log message *
* @param e
* The exception that reflects the condition.
*/
public void debug(String msg, Throwable e) {
doLog(msg, LOG_DEBUG, null, e);
}
/**
* * Log a debug level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with. *
* @param e
* The exception that reflects the condition.
*/
public void debug(String msg, ServiceReference sr, Throwable e) {
doLog(msg, LOG_DEBUG, sr, e);
}
/**
* * Log an info level message. * *
*
* @param msg
* Log message
*/
public void info(String msg) {
doLog(msg, LOG_INFO, null, null );
}
/**
* * Log an info level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with.
*/
public void info(String msg, ServiceReference sr) {
doLog(msg, LOG_INFO, sr, null );
}
/**
* * Log an info level message. * *
*
* @param msg
* Log message *
* @param e
* The exception that reflects the condition.
*/
public void info(String msg, Throwable e) {
doLog(msg, LOG_INFO, null, e);
}
/**
* * Log an info level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with. *
* @param e
* The exception that reflects the condition.
*/
public void info(String msg, ServiceReference sr, Throwable e) {
doLog(msg, LOG_INFO, sr, e);
}
/**
* * Log a warning level message. * *
*
* @param msg
* Log message
*/
public void warn(String msg) {
doLog(msg, LOG_WARNING, null, null );
}
/**
* * Log a warning level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with.
*/
public void warn(String msg, ServiceReference sr) {
doLog(msg, LOG_WARNING, sr, null );
}
/**
* * Log a warning level message. * *
*
* @param msg
* Log message *
* @param e
* The exception that reflects the condition.
*/
public void warn(String msg, Throwable e) {
doLog(msg, LOG_WARNING, null, e);
}
/**
* * Log a warning level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with. *
* @param e
* The exception that reflects the condition.
*/
public void warn(String msg, ServiceReference sr, Throwable e) {
doLog(msg, LOG_WARNING, sr, e);
}
/**
* * Log an error level message. * *
*
* @param msg
* Log message
*/
public void error(String msg) {
doLog(msg, LOG_ERROR, null, null );
}
/**
* * Log an error level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with.
*/
public void error(String msg, ServiceReference sr) {
doLog(msg, LOG_ERROR, sr, null );
}
/**
* * Log an error level message. * *
*
* @param msg
* Log message *
* @param e
* The exception that reflects the condition.
*/
public void error(String msg, Throwable e) {
doLog(msg, LOG_ERROR, null, e);
}
/**
* * Log an error level message. * *
*
* @param msg
* Log message *
* @param sr
* The ServiceReference of the service * that this
* message is associated with. *
* @param e
* The exception that reflects the condition.
*/
public void error(String msg, ServiceReference sr, Throwable e) {
doLog(msg, LOG_ERROR, sr, e);
}
/**
* * Log a message. * The ServiceDescription field and the Throwable * field
* of the LogEntry will be set to null. *
*
* @param level
* The severity of the message. (Should be one of the * four
* predefined severities.) *
* @param message
* Human readable string describing the condition.
*/
public void log(int level, String message) {
doLog(message, level, null, null );
}
/**
* * Log a message with an exception. * The ServiceDescription field of the
* LogEntry will be set to null. *
*
* @param level
* The severity of the message. (Should be one of the * four
* predefined severities.) *
* @param message
* Human readable string describing the condition. *
* @param exception
* The exception that reflects the condition.
*/
public void log(int level, String message, Throwable exception) {
doLog(message, level, null, exception);
}
/**
* * Log a message associated with a specific Service. * The Throwable field
* of the LogEntry will be set to null. *
*
* @param sr
* The ServiceReference of the service that * this
* message is associated with. *
* @param level
* The severity of the message. (Should be one of the * four
* predefined severities.) *
* @param message
* Human readable string describing the condition.
*/
public void log(ServiceReference sr, int level, String message) {
doLog(message, level, sr, null );
}
/**
* * Log a message with an exception associated with a specific Service. *
*
* @param sr
* The ServiceReference of the service that * this
* message is associated with. *
* @param level
* The severity of the message. (Should be one of the * four
* predefined severities.) *
* @param message
* Human readable string describing the condition. *
* @param exception
* The exception that reflects the condition.
*/
public void log(ServiceReference sr, int level, String message,
Throwable exception) {
doLog(message, level, sr, exception);
}
/**
* * Returns a human readable name for the bundle that * bc
* represents. *
*
* @return Name of the bundle that uses this wrapper * (at least 12
* characters).
*/
private String getBundleName() {
StringBuffer bundleName = new StringBuffer(24);
// We can't get bundle-name since it requires AdminPermission.
// bundleName.append((String)bc.getBundle().getHeaders().get("Bundle-Name"));
// If name was not found use the Bid as name.
if (bundleName.length() <= 0) {
bundleName.append("bid#");
bundleName.append(String.valueOf(bundleId));
}
if (bundleName.length() < 12) {
bundleName.append(" ");
bundleName.setLength(12);
}
return bundleName.toString();
}
}
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