jespa.util

Class LogStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.io.PrintStream

jespa.util.LogStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.Appendable, java.lang.AutoCloseable

public class LogStream
extends java.io.PrintStream

A simple PrintStream with an integer log level. A single instance is used for logging throughout the Jespa library as illustrated by the following code fragment:

LogStream log = LogStream.getInstance();
if (log.level >= 2) {
    log.println("SomeIdentifier: If the level is 2 or above, this message will be logged.");
}

Messages should be prefixed with an identifier followed immediately by a colon. Alternative LogStream implementaitons can use this identifier as a selector. This convention is not required but it is used throughout the Jespa codebase (with the exception of stack traces because they span multiple lines).

Log level values are described in the following table. The default log level is 1 to indicate only critical information should be logged.

To redirect logging in Jespa to an alternative logging solution (such as java.util.logging), use setInstance(java.io.PrintStream) to install an implementation of PrintStream.

LogStream log levels

Level	Description
0	Nothing.
1	Log critical information only. The is the default level value.
2	Basic information that can be logged under load.
3	More detailed information that should not significantly effect application performace but should only be used intermittently as it could result in excessive log entries.
4+	Level 4 and higher should be used for debugging purposes only.

Field Summary

Fields

Modifier and Type	Field and Description
static int	level The level of information to log.

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor and Description
LogStream(java.io.OutputStream out)

Method Summary

Modifier and Type	Method and Description
static LogStream	getInstance() Get the shared static log stream instance.
void	println(java.lang.Object o)
void	println(java.lang.String s)
static void	setInstance(java.io.PrintStream stream) Set the shared static stream that should be used throughout the Jespa library.
static void	setLevel(int level) Set the level of information that should be logged.
java.lang.String	toString()

Methods inherited from class java.io.PrintStream

append, append, append, checkError, clearError, close, flush, format, format, print, print, print, print, print, print, print, print, print, printf, printf, println, println, println, println, println, println, println, println, setError, write, write

Methods inherited from class java.io.FilterOutputStream

write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

level

public static int level

The level of information to log. See table above.

See Also:

setLevel(int)

Constructor Detail

LogStream

public LogStream(java.io.OutputStream out)

Method Detail

setLevel

public static void setLevel(int level)

Set the level of information that should be logged.

See Also:

level

setInstance

public static void setInstance(java.io.PrintStream stream)

Set the shared static stream that should be used throughout the Jespa library.

To control where data is written, supply an instance of PrintStream with a write(byte[]) method that writes the log message to the desired sink. This class's default implementations of println will call write(byte[]) with each log message and a platform appropritate line break.

To modify the content of each log message, the stream parameter should be an instance of LogStream that overrides the println(String) and println(Object) methods to modify the message as necessary and then call the super method with the same signature (or write(byte[]) could be called directly).

getInstance

public static LogStream getInstance()

Get the shared static log stream instance. Unless set with setInstance(java.io.PrintStream), the default LogStream is one created with the System.err stream.

println

public void println(java.lang.Object o)

Overrides:

println in class java.io.PrintStream

println

public void println(java.lang.String s)

Overrides:

println in class java.io.PrintStream

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object