com.p6spy.engine.outage

Enum P6OutageDetector

java.lang.Object

java.lang.Enum<P6OutageDetector>

com.p6spy.engine.outage.P6OutageDetector

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<P6OutageDetector>, java.lang.Runnable

public enum P6OutageDetector
extends java.lang.Enum<P6OutageDetector>
implements java.lang.Runnable

This class is a singleton. Since P6Spy is normally loaded by the system classpath, it is a normally a singleton across the JVM. The instance will determine if a statement has been long running and log the statement when such a statment is found. It accomplishes this by spawning a daemon thread which will wake up at configurable intervals of time (defined in seconds) and check if a statement is still executing since the last time the thread was awake. This is accomplished by this instance maintaining a list of active statements. The P6Statement and P6PreparedStatement objects will reqister their call with the instance just before the SQL call is delegated to the real driver. Once that statement finishes executing, the statement object will unregister that call from list. If during that time the thread in this instance sees the execute time exceed the threshold, it is flagged as a long-running statement and logged. The statement will continue to be logged if it appears in future iterations of the sleep/wake cycle. This class is implemented with lazy thread sychronization. The list of pending statements is a synchronized container, the rest is left open to thread hazards to reduce the performance impact. So the logging results might be slightly unreliable, but we aren't dealing with bank accounts here so thats okay.

Enum Constant Summary

Enum Constants

Enum Constant and Description
INSTANCE

Method Summary

Modifier and Type	Method and Description
void	registerInvocation(java.lang.Object jdbcObject, long startTime, java.lang.String category, java.lang.String ps, java.lang.String sql, java.lang.String url) Registers the execution of a statement.
void	run() Method for running the auxillary thread.
void	shutdown() Tells the auxillary thread to stop executing.
void	unregisterInvocation(java.lang.Object jdbcObject) Unregisters the execution of a statement.
static P6OutageDetector	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static P6OutageDetector[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

INSTANCE

public static final P6OutageDetector INSTANCE

Method Detail

values

public static P6OutageDetector[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (P6OutageDetector c : P6OutageDetector.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static P6OutageDetector valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

run

public void run()

Method for running the auxillary thread.

Specified by:

run in interface java.lang.Runnable

shutdown

public void shutdown()

Tells the auxillary thread to stop executing. Thread will exit upon waking next.

registerInvocation

public void registerInvocation(java.lang.Object jdbcObject,
                               long startTime,
                               java.lang.String category,
                               java.lang.String ps,
                               java.lang.String sql,
                               java.lang.String url)

Registers the execution of a statement. This should be called just before the statement is passed to the real driver.

unregisterInvocation

public void unregisterInvocation(java.lang.Object jdbcObject)

Unregisters the execution of a statement. This should be called just after the statement is passed to the real driver.