patternjavaMinor

Determine maximum window bounds

Submitted by: @import:stackexchange-codereview·Mar 10, 2026·

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windowboundsmaximumdetermine

Problem

Preamble: the default frame positioning with Swing JFrames has always bothered me. Eventually I wrote some code to calculate my available desktop space, not counting my abnormally-large right-side-anchored taskbar, and use that information to size and position my JFrames. Then I got sick of copy/pasting the same frame size calculations into every Main.java of every pet project I make. So, I spent the better part of today writing a one-class library to centralize the functionality. I'm just doing this for practice and my own twisted sense of hard-working laziness, but it is complete and functioning code.

What I would like feedback on: the usual best practices for Java and Swing, naming of the class/methods/parameters of the public interface, and if it's not too much trouble I would also like feedback on the Javadoc I've written, since I've never written this level of documentation for professional projects.

I published a PDF of the javadoc and uploaded it so it's not necessary to read through the markup for that. It will be available here for one week.

The first thing I expect to be criticized is the name—I'm unhappy with TlcSizer, which was based on the initialism for top-level container, but FrameSizer was too specific and I'm not sure what would be both clear and concise.

TlcSizer.java:

```
package tlcsizer;

import java.awt.Dimension;
import java.awt.GraphicsEnvironment;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Window;
import javax.swing.LookAndFeel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

/**
* {@code TlcSizer} is a utility class for Swing user interfaces to determine
* top-level component bounds based on screen size and available screen space.
* This class is designed so that you can acquire an instance prior to
* initializing your interface, which minimizes the impact of changing the
* {@link LookAndFeel}. By aquiring a sizer instance and using only
* instance methods, you c

Solution

General

Your variable names are not helpful enough. I understand that mwb is maximum window bounds, but it is still too short.

In general, I worry that you have too many different ways to access the core logic. Too many public methods.

Further, some of your methods require a TlcSizer instance, but others are just public static methods. This inconsistency is confusing.

On the other hand, the JavaDoc is neat and consistent. I like the detail you have (but I am a lots-of-detail-person, I know other people who will think you have overdone it). I can tell you have paid attention to paragraphs, and other formatting in the JavaDoc.

Out of interest, when you have a

in the JavaDoc, I suggest also adding an empty line to make it a paragraph in the code format too, and also have an empty line before the @param sections. For example, your JavaDoc:

/**
 * Creates a new {@code FrameSizer}, setting the look and feel as
 * specified. This constructor needs to alter the current
 * look and feel to account for objects in the native windowing
 * system such as task bars and menu bars in calculating the available
 * screen space. After performing this calculation, the specified
 * look and feel will be set.
 * The {@code FrameSizer} class is designed so that you can acquire an
 * instance prior to initializing your interface, which minimizes the impact
 * of changing the look and feel. This constructor is best used
 * as a replacement for setting the look and feel in client code.
 * Warning: this constructor alters the current
 * look and feel. This will cause strange behaviour in your
 * application if your interface has already been initialized. If this is
 * the case, you must call {@link
 * javax.swing.SwingUtilities#updateComponentTreeUI(java.awt.Component)}
 * once for each top-level container. It is recommended that you
 * re-{@link Window#pack() pack} your top-level container after this
 * operation.
 * @param lookAndFeel the name of the {@link LookAndFeel} to set
 * @throws tlcsizer.TlcSizer.TlcSizerException if there was a
 * problem setting the look and feel
 */

would be better if written:

/**
 * Creates a new {@code FrameSizer}, setting the look and feel as
 * specified. This constructor needs to alter the current
 * look and feel to account for objects in the native windowing
 * system such as task bars and menu bars in calculating the available
 * screen space. After performing this calculation, the specified
 * look and feel will be set.
 * 
 * The {@code FrameSizer} class is designed so that you can acquire an
 * instance prior to initializing your interface, which minimizes the impact
 * of changing the look and feel. This constructor is best used
 * as a replacement for setting the look and feel in client code.
 * 
 * Warning: this constructor alters the current
 * look and feel. This will cause strange behaviour in your
 * application if your interface has already been initialized. If this is
 * the case, you must call {@link
 * javax.swing.SwingUtilities#updateComponentTreeUI(java.awt.Component)}
 * once for each top-level container. It is recommended that you
 * re-{@link Window#pack() pack} your top-level container after this
 * operation.
 * 
 * @param lookAndFeel the name of the {@link LookAndFeel} to set
 * @throws tlcsizer.TlcSizer.TlcSizerException if there was a
 * problem setting the look and feel
 */

Bugs

In this method I believe you have a bug:

private static boolean setBounds(Window window, Rectangle mwb,
        ReferenceRegion region) {
    window.pack();
    final Rectangle newBounds = getCentredBounds(window.getPreferredSize(),
            mwb, region);
    final boolean wasTlcModified = newBounds.equals(window.getBounds());
    if (wasTlcModified) {
        window.setBounds(newBounds);
    }
    return wasTlcModified;
}

The boolean wasTlcModified should be the negated value of newBounds.equals(window.getBounds()).

A second bug, in private static Rectangle getCentredBounds(Dimension, Rectangle, ReferenceRegion), you have the option of AVAILABLE_SPACE as the region. From what I can see, that option does nothing. It sets the values of the x and y variables, but then does nothing with those values. What is the point?

Style

1-liners (even simple ones) should have {} braces:

if (max < min) throw new ArithmeticException();

should be:

if (max < min) {
    throw new ArithmeticException();
}

Additionally, adding a useful message would be good:

if (max < min) {
    throw new ArithmeticException(String.format(
        "Specified min value %d is larger than the specified max value %d", min, max));
}

Actually, if it was me, I would just remove the check since I have full control over the code, and I can't see how the condition is violated. But, you have assert statements in other places so I am not sure why you don't just assert this condition too. Consistency is always important. Hmm, while looking at the me

Code Snippets

/**
 * Creates a new {@code FrameSizer}, setting the look&nbsp;and&nbsp;feel as
 * specified. This constructor needs to alter the current
 * look&nbsp;and&nbsp;feel to account for objects in the native windowing
 * system such as task bars and menu bars in calculating the available
 * screen space. After performing this calculation, the specified
 * look&nbsp;and&nbsp;feel will be set.
 * <p>The {@code FrameSizer} class is designed so that you can acquire an
 * instance prior to initializing your interface, which minimizes the impact
 * of changing the look&nbsp;and&nbsp;feel. This constructor is best used
 * as a replacement for setting the look&nbsp;and&nbsp;feel in client code.
 * <p><b>Warning:</b> this constructor alters the current
 * look&nbsp;and&nbsp;feel. This will cause strange behaviour in your
 * application if your interface has already been initialized. If this is
 * the case, you must call {@link
 * javax.swing.SwingUtilities#updateComponentTreeUI(java.awt.Component)}
 * once for each top-level container. It is recommended that you
 * re-{@link Window#pack() pack} your top-level container after this
 * operation.
 * @param lookAndFeel the name of the {@link LookAndFeel} to set
 * @throws tlcsizer.TlcSizer.TlcSizerException if there was a
 * problem setting the look&nbsp;and&nbsp;feel
 */

/**
 * Creates a new {@code FrameSizer}, setting the look&nbsp;and&nbsp;feel as
 * specified. This constructor needs to alter the current
 * look&nbsp;and&nbsp;feel to account for objects in the native windowing
 * system such as task bars and menu bars in calculating the available
 * screen space. After performing this calculation, the specified
 * look&nbsp;and&nbsp;feel will be set.
 * <p>
 * The {@code FrameSizer} class is designed so that you can acquire an
 * instance prior to initializing your interface, which minimizes the impact
 * of changing the look&nbsp;and&nbsp;feel. This constructor is best used
 * as a replacement for setting the look&nbsp;and&nbsp;feel in client code.
 * <p>
 * <b>Warning:</b> this constructor alters the current
 * look&nbsp;and&nbsp;feel. This will cause strange behaviour in your
 * application if your interface has already been initialized. If this is
 * the case, you must call {@link
 * javax.swing.SwingUtilities#updateComponentTreeUI(java.awt.Component)}
 * once for each top-level container. It is recommended that you
 * re-{@link Window#pack() pack} your top-level container after this
 * operation.
 * 
 * @param lookAndFeel the name of the {@link LookAndFeel} to set
 * @throws tlcsizer.TlcSizer.TlcSizerException if there was a
 * problem setting the look&nbsp;and&nbsp;feel
 */

private static boolean setBounds(Window window, Rectangle mwb,
        ReferenceRegion region) {
    window.pack();
    final Rectangle newBounds = getCentredBounds(window.getPreferredSize(),
            mwb, region);
    final boolean wasTlcModified = newBounds.equals(window.getBounds());
    if (wasTlcModified) {
        window.setBounds(newBounds);
    }
    return wasTlcModified;
}

if (max < min) throw new ArithmeticException();

if (max < min) {
    throw new ArithmeticException();
}

Context

StackExchange Code Review Q#61136, answer score: 4

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