A printable utility class.

Printable.java

package jab.util;


/**
 * Interface designed to handle advanced printing. Only available in JDK8+.
 * 
 * @author Jab
 *
 */
public interface Printable {
	
	public static boolean PRINT_NEW_LINE = false;

	/**
	 * Static shortcut to the newline property from the System running this
	 * program.
	 */
	static String newLine = System.getProperty("line.separator");

	/**
	 * Prints lines with "getName(): [message...]".
	 * 
	 * @param messages
	 */
	public default void println(Object... messages) {

		if (messages.length == 0) {
			System.out.println();
		} else {
			// Grab the name of the instance.
			String name = getName();

			// Create the header, based on if the name String is null of empty.
			String header = name == null || name.isEmpty() ? "" : name + ": ";

			// Go through each Object, and print them as a separate line.
			String compiledString = "";
			for (Object message : messages) {
				compiledString += header + message + (PRINT_NEW_LINE ? newLine : "");
			}

			// Print the result.
			System.out.print(Indentation.getIndentationsString() + compiledString);
		}
	}

	/**
	 * Prints lines with "getName(): [message...]".
	 * 
	 * @param messages
	 */
	public default void errln(Object... messages) {

		if (messages.length == 0) {
			System.err.println();
		} else {
			// Grab the name of the instance.
			String name = getName();

			// Create the header, based on if the name String is null of empty.
			String header = name == null || name.isEmpty() ? "" : name + ": ";

			// Go through each Object, and print them as a separate line.
			String compiledString = "";
			for (Object message : messages) {
				compiledString += header + message + (PRINT_NEW_LINE ? newLine : "");
			}

			// Print the result.
			System.err.print(Indentation.getIndentationsString() + compiledString);
		}
	}

	/**
	 * Prints a message with a header, without a new-line.
	 * 
	 * @param message
	 */
	public default void printH(Object message) {

		// Grab the name of the instance.
		String name = getName();

		// Create the header, based on if the name String is null of empty.
		String header = name == null || name.isEmpty() ? "" : name + ": ";

		// Print the result.
		System.out.print(Indentation.getIndentationsString() + header + message);
	}

	/**
	 * Prints a message, without a new-line.
	 * 
	 * @param message
	 */
	public default void print(Object message) {
		// Print the result.
		System.out.print(message);
	}

	/**
	 * 
	 * @param throwable
	 */
	public default void stackTrace(Throwable throwable) {
		stackTrace(throwable.getClass().getName(), throwable);
	}

	/**
	 * 
	 * @param errorText
	 * @param throwable
	 */
	public default void stackTrace(String errorText, Throwable throwable) {
		if (errorText != null && !errorText.isEmpty()) {
			errorText = errorText.trim() + ": " + throwable.getCause();
		}

		errln("Error: " + (errorText != null ? errorText : "") + ": " + throwable.getMessage());
		for (StackTraceElement element : throwable.getStackTrace()) {
			errln(element);
		}
	}

	/**
	 * 
	 */
	public default void stackTrace() {
		for (StackTraceElement element : Thread.currentThread().getStackTrace()) {
			errln(element);
		}
	}

	/**
	 * Returns the Class name as a String.
	 * 
	 * @return
	 */
	public default String getClassName() {
		String[] split = getClass().getName().split("\\.");
		return split[split.length - 1];
	}

	/**
	 * Globally indents all Printable Objects by 1. (uses \t for every
	 * indentation)
	 */
	public default void indent() {
		indent(1);
	}

	/**
	 * Globally indents all Printable Objects by a given amount. (uses /t for
	 * every indentation)
	 * 
	 * @param amount
	 */
	public default void indent(int amount) {
		Indentation.indent(amount);
	}

	/**
	 * Globally unindents all Printable Objects by 1. (uses /t for every
	 * indentation)
	 */
	public default void unindent() {
		unindent(1);
	}

	/**
	 * Globally unindents all Printable Objects by a given amount. (uses /t for
	 * every indentation)
	 * 
	 * @param amount
	 */
	public default void unindent(int amount) {
		Indentation.unindent(amount);
	}

	public default void resetIndentation() {
		Indentation.reset();
	}

	/**
	 * Grabs the name of the instance.
	 * 
	 * @return
	 */
	public String getName();

}

/**
 * Appended Class to handle the static indentation functionality of Printable.
 * 
 * @author Jab
 *
 */
final class Indentation {

	/** The amount of indentations for a print. */
	static int indentations = 0;

	/** The rendered indentations string. */
	static String _indentationsString = "";

	/** Flag to note when the indentations string needs to be re-rendered. */
	static boolean dirty;

	/**
	 * Globally indents all Printable Objects by 1. (uses /t for every
	 * indentation)
	 */
	static void indent(int value) {
		indentations += value;
		dirty = true;
	}

	/**
	 * Resets indentation.
	 */
	static void reset() {
		indentations = 0;
		dirty = true;
	}

	/**
	 * Globally unindents all Printable Objects by 1. (uses /t for every
	 * indentation)
	 */
	static void unindent(int value) {
		indentations -= value;
		dirty = true;
	}

	/**
	 * Returns a built String to represent the amount of indentations a
	 * Printable Object uses when printing.
	 * 
	 * @return
	 */
	static String getIndentationsString() {

		// If dirty, rebuild the rendered indentation String.
		if (dirty) {

			// Reset the String.
			_indentationsString = "";

			// Loop through each count, adding a new tab to the rendered String.
			for (int index = 0; index < Indentation.indentations; index++) {
				_indentationsString += "\t";
			}

			// Set the dirty flag to false, as we have rendered the indentation
			// String.
			dirty = false;
		}

		// Return the rendered indentation String.
		return _indentationsString;
	}
}