de.unkrig.commons.text

Class Printers

java.lang.Object

de.unkrig.commons.text.Printers

public final class Printers
extends java.lang.Object

A super-simple API for managing output of different kinds. Basically an alternative for "System.out.println()" and "System.err.println()", with much more flexibility.

This concept borrows from the various "logging" frameworks, but differs in several ways:

• It is made for "foreground processing", e.g. command line tools that output messages as they process data.
• It is inherently thread-oriented and not application-global.
• It is not oriented "by class" but only "by level".
• The output is intended for users and administrators, and not so much for programmers.

Five levels of output exist:

• "Debug" output, e.g. the progress of the creation of a connection
• "Verbose" output, e.g. the names of files as they are processed
• "Info" output, e.g. the matched found by a GREP utility
• "Warn" output
• "Error" output

Use the error(), warn(), info(), verbose() and debug() methods to print to the "current context".

The "initial context" (which is in effect iff withPrinter(Printer, Runnable) has not yet been called) prints errors and warnings to System.err and infos, verbose and debug to System.out.

In many cases, you want to use a LevelFilteredPrinter in a very early stage to configure how output is printed:

     public static void
     main(final String... args) {

         final Main main = new Main();
         Printers.withPrinter(main.levelFilteredPrinter, new Runnable() {

             @Override public void run() { main.main2(args); }
         });
     }

     private final LevelFilteredPrinter levelFilteredPrinter = new LevelFilteredPrinter(Printers.get());

     private void
     main2(String[] args) {

         // As an example, we enable verbose messages here. You would typically do that as a reaction to a
         // "--verbose" command line option.
         levelFilteredPrinter.setVerbose();

         Printers.debug("foo");   // Not printed, because debug level was not enabled on the levelFilteredPrinter
         Printers.verbose("foo"); // Prints to STDOUT, because verbose messages were enabled above.
         Printers.info("foo");    // Prints to STDOUT
         Printers.warn("foo");    // prints to STDERR
         Printers.err("foo");     // prints to STDERR
     }

 

See Also:

withPrinter(Printer, Runnable), withPrinter(Printer, RunnableWhichThrows)

Method Summary

Modifier and Type	Method and Description
static void	debug(java.lang.String message) Prints a debug message on the context printer.
static void	debug(java.lang.String pattern, java.lang.Object... arguments) Prints a debug message on the context printer.
static void	error(java.lang.String message) Prints an error condition on the context printer.
static void	error(java.lang.String pattern, java.lang.Object... arguments) Prints an error condition on the context printer.
static void	error(java.lang.String message, java.lang.Throwable t) Prints an error condition on the context printer.
static void	error(java.lang.String pattern, java.lang.Throwable t, java.lang.Object... arguments) Prints an error condition on the context printer.
static Printer	get()
static void	info(java.lang.String message) Prints an informative ("normal") message on the context printer.
static void	info(java.lang.String pattern, java.lang.Object... arguments) Prints an informative ("normal") message on the context printer.
static <EX extends java.lang.Throwable> void	redirectInfo(ConsumerWhichThrows<? super java.lang.String,? extends java.lang.RuntimeException> infoConsumer, RunnableWhichThrows<? extends EX> runnable) Runs the runnable with its INFO output redirected to the infoConsumer.
static <EX extends java.lang.Throwable> void	redirectInfo(java.io.Writer writer, RunnableWhichThrows<EX> runnable) Runs the runnable with its INFO output redirected to the writer.
static <EX extends java.lang.Throwable> void	redirectInfoToFile(java.io.File file, RunnableWhichThrows<EX> runnable) Runs the runnable with its INFO output redirected into the file.
static void	verbose(java.lang.String message) Prints a verbose message on the context printer.
static void	verbose(java.lang.String pattern, java.lang.Object... arguments) Prints a verbose message on the context printer.
static void	warn(java.lang.String message) Prints a warning condition on the context printer.
static void	warn(java.lang.String pattern, java.lang.Object... arguments) Prints a warning condition on the context printer.
static void	withPrinter(Printer printer, java.lang.Runnable runnable) Replaces the context printer with the given printer while the runnable is running.
static <EX extends java.lang.Throwable> void	withPrinter(Printer printer, RunnableWhichThrows<EX> runnable) Replaces the context printer with the given printer while the runnable is running.

Methods inherited from class java.lang.Object

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

Method Detail

get

public static Printer get()

Returns:

the context printer for this thread

error

public static void error(@Nullable
                         java.lang.String message)

Prints an error condition on the context printer.

error

public static void error(java.lang.String pattern,
                         java.lang.Object... arguments)

Prints an error condition on the context printer.

See Also:

MessageFormat

error

public static void error(@Nullable
                         java.lang.String message,
                         java.lang.Throwable t)

Prints an error condition on the context printer.

error

public static void error(java.lang.String pattern,
                         java.lang.Throwable t,
                         java.lang.Object... arguments)

Prints an error condition on the context printer.

See Also:

MessageFormat

warn

public static void warn(@Nullable
                        java.lang.String message)

Prints a warning condition on the context printer.

warn

public static void warn(java.lang.String pattern,
                        java.lang.Object... arguments)

Prints a warning condition on the context printer.

See Also:

MessageFormat

info

public static void info(@Nullable
                        java.lang.String message)

Prints an informative ("normal") message on the context printer.

info

public static void info(java.lang.String pattern,
                        java.lang.Object... arguments)

Prints an informative ("normal") message on the context printer.

See Also:

MessageFormat

verbose

public static void verbose(@Nullable
                           java.lang.String message)

Prints a verbose message on the context printer.

verbose

public static void verbose(java.lang.String pattern,
                           java.lang.Object... arguments)

Prints a verbose message on the context printer.

See Also:

MessageFormat

debug

public static void debug(@Nullable
                         java.lang.String message)

Prints a debug message on the context printer.

debug

public static void debug(java.lang.String pattern,
                         java.lang.Object... arguments)

Prints a debug message on the context printer.

See Also:

MessageFormat

withPrinter

public static void withPrinter(Printer printer,
                               java.lang.Runnable runnable)

Replaces the context printer with the given printer while the runnable is running.

withPrinter

public static <EX extends java.lang.Throwable> void withPrinter(Printer printer,
                                                                RunnableWhichThrows<EX> runnable)
                                                         throws EX extends java.lang.Throwable

Replaces the context printer with the given printer while the runnable is running.

Throws:

EX extends java.lang.Throwable

redirectInfoToFile

public static <EX extends java.lang.Throwable> void redirectInfoToFile(@Nullable
                                                                       java.io.File file,
                                                                       RunnableWhichThrows<EX> runnable)
                                                                throws java.io.IOException,
                                                                       EX extends java.lang.Throwable

Runs the runnable with its INFO output redirected into the file. If the runnable throws an exception, then the file is closed, but not deleted.

Iff the file is null, then the INFO output is not redirected.

Throws:

java.io.IOException

EX extends java.lang.Throwable

redirectInfo

public static <EX extends java.lang.Throwable> void redirectInfo(@Nullable
                                                                 java.io.Writer writer,
                                                                 RunnableWhichThrows<EX> runnable)
                                                          throws EX extends java.lang.Throwable

Runs the runnable with its INFO output redirected to the writer. Iff the writer is null, then the INFO output is not redirected.

Throws:

EX extends java.lang.Throwable

redirectInfo

public static <EX extends java.lang.Throwable> void redirectInfo(@Nullable
                                                                 ConsumerWhichThrows<? super java.lang.String,? extends java.lang.RuntimeException> infoConsumer,
                                                                 RunnableWhichThrows<? extends EX> runnable)
                                                          throws EX extends java.lang.Throwable

Runs the runnable with its INFO output redirected to the infoConsumer. Iff the infoConsumer is null, then the INFO output is not redirected.

Throws:

EX extends java.lang.Throwable