jpos.util.tracing.Tracer Maven / Gradle / Ivy
package jpos.util.tracing;
///////////////////////////////////////////////////////////////////////////////
//
// This software is provided "AS IS". The JavaPOS working group (including
// each of the Corporate members, contributors and individuals) MAKES NO
// REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE,
// EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
// WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NON-INFRINGEMENT. The JavaPOS working group shall not be liable for
// any damages suffered as a result of using, modifying or distributing this
// software or its derivatives. Permission to use, copy, modify, and distribute
// the software and its documentation for any purpose is hereby granted.
//
// The JavaPOS Config/Loader (aka JCL) is now under the CPL license, which
// is an OSS Apache-like license. The complete license is located at:
// http://www.ibm.com/developerworks/library/os-cpl.html
//
///////////////////////////////////////////////////////////////////////////////
import jpos.util.*;
import java.io.PrintStream;
/**
* Tracing class to help in the debugging of other package code
*
* -
* Note 1: this class is a Singleton (see GoF Design Pattern book)
* ccess the sole instance by doing: Tracer.getInstance() call
*
* -
* Note 2: Will allow (in the future) the option of defining different
* ouput for the tracer (1.3 version)
*
* -
* By default Tracer objects are turned OFF but can dynamically or via
* properties file be turned OFF
*
*
* @see Tracer#getInstance()
* @author E. Michael Maximilien
* @since 2.1.0
*/
public class Tracer extends Object
{
//-------------------------------------------------------------------------
// Ctor
//
/** Make ctor private to avoid construction (this is a Singleton class) */
protected Tracer() { appendName = false; }
/**
* Creates a Tracer instance with name specified
* @param name the Tracer name
*/
Tracer( String name )
{
if( name == null || name.equals( "" ) )
{
appendName = false;
tracerName = "";
onTracerOutput = new DefaultTracerOutput();
}
else
{
appendName = true;
onTracerOutput = new DefaultTracerOutput( "[" + name + "]" );
tracerName = name;
}
}
//-------------------------------------------------------------------------
// Public class methods
//
/** @return the sole instance of this class (creating it if necessary) */
public static Tracer getInstance()
{
if( instance == null )
{
instance = new Tracer();
instance.init();
}
return instance;
}
//-------------------------------------------------------------------------
// Public methods
//
/**
* Prints a string appended with a new line to the tracer output
* @param s the String to print
*/
public void println( String s ) { getTracerOutput().println( s ); }
/**
* Prints the String representation of the Object passed
* @param obj the Object to println
*/
public void println( Object obj ) { getTracerOutput().println( obj.toString() ); }
/**
* Prints a string appended without a new line to the tracer output
* @param s the String to print
*/
public void print( String s ) { getTracerOutput().print( s ); }
/**
* Prints a String representation of the Object passed
* @param obj the Object to print
*/
public void print( Object obj ) { getTracerOutput().print( obj.toString() ); }
/**
* Prints a StackTrace from an Exception object.
* @param e the Exception to extract StackTrace from
*/
public void print( Exception e ) { getTracerOutput().print( e ); }
/** Flushes the Tracer */
public void flush() { getTracerOutput().flush(); }
/**
* Sets this tracer ON or OFF
* @param b the boolean parameter
*/
public void setOn( boolean b ) { tracerOn = b; }
/** @return true if the tracer is ON (i.e. enabled) */
public boolean isOn() { return tracerOn; }
/** @return this Tracer's name */
public String getName() { return tracerName; }
/**
* Tells Tracer instance whether it should append name for each trace
* message or not
* @param b the boolean parameter
*/
public void setAppendName( boolean b ) { appendName = b; }
/** @return whether the Tracer should append its name to each println method call */
public boolean isAppendName() { return appendName; }
//-------------------------------------------------------------------------
// Protected methods
//
//-------------------------------------------------------------------------
// Private methods
//
/** Intialize the current instance using the DefaultProperties class */
private void init()
{
JposProperties props = new DefaultProperties();
props.loadJposProperties();
if( !props.isPropertyDefined( JposProperties.TRACING_PROP_NAME ) )
setOn( false );
else
{
String tracingPropValue = props.getPropertyString( JposProperties.TRACING_PROP_NAME );
if( tracingPropValue.equalsIgnoreCase( JposProperties.TRACING_ON_PROP_VALUE ) ||
tracingPropValue.equalsIgnoreCase( JposProperties.TRACING_TRUE_PROP_VALUE ) )
setOn( true );
}
}
/** @return the tracerOutput object for the Tracer */
private TracerOutput getTracerOutput()
{
if( customTracerOutput != null ) return customTracerOutput;
return ( isOn() ? onTracerOutput : offTracerOutput );
}
//-------------------------------------------------------------------------
// Package methods
//
/**
* Sets the TracerOutput object -- for debugging purposes
* @param tracerOutput the TracerOutput object
*/
void setTracerOutput( TracerOutput tracerOutput )
{
tracerOn = true;
customTracerOutput = tracerOutput;
}
//-------------------------------------------------------------------------
// Private instance variables
//
private boolean tracerOn = false;
private String tracerName = "";
private boolean appendName = true;
private TracerOutput customTracerOutput = null;
private TracerOutput onTracerOutput = new DefaultTracerOutput();
private TracerOutput offTracerOutput = new TracerOutput()
{
public void close() {}
public String getPrefix() { return ""; }
public void print( Exception e ) {}
public void println( String s ) {}
public void print( String s ) {}
public void flush() {}
};
//-------------------------------------------------------------------------
// Private class variables
//
private static Tracer instance = null;
//-------------------------------------------------------------------------
// Private static inner classes
//
/**
* Inner class for a default TracerOutput. Just prints out info to System.err
* @author E. Michael Maximilien
*/
class DefaultTracerOutput extends Object implements TracerOutput
{
//---------------------------------------------------------------------
// Ctor(s)
//
/**
* Default ctor. No prefix is used and the PrintStream is set
* to the System.err PrintStream
*/
public DefaultTracerOutput()
{
prefix = "";
appendName = false;
}
/**
* Default ctor
* @param s the String prefix to use for this TracerOutput
*/
public DefaultTracerOutput( String s )
{
if( s == null ) prefix = "";
else
if( s.equals( "" ) ) prefix = "";
else
{
prefix = s;
appendName = true;
}
}
/**
* Default ctor
* @param s the String prefix to use for this TracerOutput
* @param pStream the PrintStream object used for this TracerOutput
*/
public DefaultTracerOutput( String s, PrintStream pStream )
{
this( s );
printStream = pStream;
}
//---------------------------------------------------------------------
// Public methods
//
/**
* @return any prefix that is to be used with this TracerOutput
* An existing prefix gets appended to every message
*/
public String getPrefix() { return prefix; }
/**
* Closes the TracerOutput. If it is a file then closes the file
* Any errors are not propagated up and rather printed to the System.errr
*/
public void close() { getPrintStream().close(); }
/**
* Prints a string appended with a new line to the tracer output
* @param s the String to print
*/
public void println( String s )
{
getPrintStream().println( ( appendName ? prefix : "" ) + s );
}
/**
* Prints a string appended without a new line to the tracer output
* @param s the String to print
*/
public void print( String s )
{
getPrintStream().print( ( appendName ? prefix : "" ) + s );
}
/**
* Prints a StackTrace from an Exception object.
* @param e the Exception to extract StackTrace from
*/
public void print( Exception e )
{
if( appendName ) System.err.println( "<" + prefix + ">" );
e.printStackTrace( getPrintStream() );
if( appendName ) System.err.println( "" );
}
/**
* Flushes this TracerOutput
*
* For this TracerOutput does not do anything since output flushes
* automatically
*
*/
public void flush() { getPrintStream().flush(); }
//-------------------------------------------------------------------------
// Protected methods
//
/** @return the PrintStream object that is used for this TracerOutput */
protected PrintStream getPrintStream() { return printStream; }
/**
* Sets the PrintStream for this TracerOutput
* @param pStream a PrintStream object
*/
protected void setPrintStream( PrintStream pStream ) { printStream = pStream; }
//-------------------------------------------------------------------------
// Instance variables
//
protected String prefix = "";
protected PrintStream printStream = System.err;
}
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