* * 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.
*
*
*
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 * TheServiceReference 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, (ServiceReference) null, (Throwable) 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, (Throwable) 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, (ServiceReference) 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, (ServiceReference) null, (Throwable) 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, (Throwable) 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, (ServiceReference) 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, (ServiceReference) null, (Throwable) 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, (Throwable) 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, (ServiceReference) 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, (ServiceReference) null, (Throwable) 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, (Throwable) 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, (ServiceReference) 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, (ServiceReference) null, (Throwable) 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, (ServiceReference) 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, (Throwable) 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();
}
}