path: root/projects/net.wotonomy.ui.swing/src/main/java/net/wotonomy/ui/swing/components/InfoPanel.java

/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2000 Blacksmith, Inc.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/

package net.wotonomy.ui.swing.components;

import java.awt.AWTEventMulticaster;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.MethodDescriptor;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import javax.swing.Box;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

/**
 * InfoPanel uses labels and textfields (or any other component - see below) to
 * display a list of keys and values in a well-aligned and consistent manner,
 * conforming to alignment and pixel spacing in the java look and feel
 * <a href="http://java.sun.com/products/jlf/dg/higg.htm#55417">design
 * guidelines</a>. <BR>
 * <BR>
 *
 * Each key is displayed in a label to the left of the component that contains
 * the corresponding value. Each row is displayed starting at the top of the
 * component's available area. Each row's height is the maximum preferred height
 * of its components and the field itself gets as much of the width as it can,
 * dependent on the length of the longest label. <BR>
 * <BR>
 *
 * The values in the fields can be editable, and the current value can be
 * retrieved using the key - for this reason, unique keys are recommended. <BR>
 * <BR>
 *
 * As a convenience, push buttons may be placed across the bottom of the panel
 * in a manner similar to ButtonPanel. <BR>
 * <BR>
 *
 * The panel forwards any ActionEvents generated by the components and buttons
 * on it to all registered listeners. <BR>
 * <BR>
 *
 * Optionally, any component can be used instead of a textfield. However,
 * <code>get/setValueForKey()</code> and <code>get/setEditable()</code> may not
 * work for those components. Use <code>getComponentForKey()</code> to access
 * them instead.
 *
 * @author michael@mpowers.net
 * @author $Author: cgruber $
 * @version $Revision: 904 $ $Date: 2006-02-18 18:19:05 -0500 (Sat, 18 Feb 2006)
 *          $
 */
public class InfoPanel extends JPanel implements ActionListener {
	/**
	 * Special label for an empty pair - a label and component that take up space
	 * but are hidden from view. This might be useful for achieving certain layouts.
	 */
	public static final String HIDDEN = "(hidden)";

	/** Cache for the introspectComponent method */
	private static Map _method_cache = Collections.synchronizedMap(new HashMap(30));

	protected Container listContainer = null;
	protected int hgap; // set in constructor
	protected int vgap; // set in constructor
	protected int margin; // set in constructor
	protected int columns; // set in constructor
	protected List<Component> fields = null;
	protected List<Component> labels = null;
	protected List<Component> fieldSpacers = null;
	protected ButtonPanel buttonPanel = null;
	protected boolean isEditable = true;
	protected String prefix;
	protected String postfix;
	protected int labelAnchor;
	protected int labelAlign;
//    protected Component marginStrut = null;

	// for action multicasting
	protected ActionListener actionListener = null;

	/**
	 * Constructs an empty InfoPanel.
	 */
	public InfoPanel() {
		hgap = 12; // per java l&f guidelines
		vgap = 6; // java l&f says 11
		columns = 1; // default columns
		margin = 0; // default margin: none
		prefix = ""; // default prefix: none
		postfix = ":"; // per java l&f guidelines
		fields = new ArrayList<>();
		labels = new ArrayList<>();
		labelAnchor = GridBagConstraints.NORTHWEST;
		// per java l&f guidelines (CENTER is nicer)
		labelAlign = SwingConstants.LEFT;
		// per java l&f guidelines

		doInitialLayout();
	}

	/**
	 * Constructs an InfoPanel with the specified labels each paired with a blank
	 * textfield.
	 * 
	 * @param labelArray An Array containing the labels in the order in which they
	 *                   should appear from top to bottom. A null value produces an
	 *                   empty panel.
	 */
	public InfoPanel(String[] labelArray) {
		this();
		setLabels(labelArray);
	}

	/**
	 * Creates a set of labels and empty textfields after first clearing all
	 * existing components on the panel.
	 * 
	 * @param labelArray An Array containing the labels in the order in which they
	 *                   should appear from top to bottom. A null value will clear
	 *                   the panel.
	 */
	public void setLabels(String[] labelArray) {
		removeAll();
		if (labelArray == null)
			return; // null clears panel
		for (int i = 0; i < labelArray.length; i++) {
			addPair(labelArray[i], new JTextField());
		}
	}

	/**
	 * Retrieves the labls for the components on the panel in the order in which
	 * they are displayed from top WIDTH bottom. These are the keys used to
	 * reference values or to reference the components directly.
	 * 
	 * @return An Array of Strings containing the labels.
	 */
	public String[] getLabels() {
		int length = fields.size();
		String[] labelArray = new String[length];
		for (int i = 0; i < length; i++) {
			labelArray[i] = ((Component) fields.get(i)).getName();
		}
		return labelArray;
	}

	/**
	 * Retrieves the constant used to anchor the labels in place. The default value
	 * is GridBagConstraints.NORTHWEST.
	 */
	public int getLabelAnchor() {
		return labelAnchor;
	}

	/**
	 * Sets the constant used to anchor the labels in place and reflows the layout.
	 * 
	 * @param anAnchorConstant An anchor constant from GridBagConstraints.
	 */
	public void setLabelAnchor(int anAnchorConstant) {
		labelAnchor = anAnchorConstant;
		updateLabels();
	}

	/**
	 * Retrieves the constant used to align the labels in place. The default value
	 * is GridBagConstraints.CENTER.
	 */
	public int getLabelAlignment() {
		return labelAlign;
	}

	/**
	 * Sets the constant used to align the labels in place and reflows the layout.
	 * 
	 * @param anAlignmentConstant LEFT, CENTER, or RIGHT constants from
	 *                            SwingUtilities.
	 */
	public void setLabelAlignment(int anAlignmentConstant) {
		labelAlign = anAlignmentConstant;
		updateLabels();
	}

	/**
	 * Factory method for creating panel spacers. This implementation returns a
	 * JPanel with opaque set to false. Override to customize.
	 */
	public JPanel createPanel() {
		JPanel result = new JPanel();
		result.setOpaque(false);
		return result;
	}

	/**
	 * This method is responsible for the initial layout of the panel. All labels
	 * and textfields will later added to listContainer. This method is responsible
	 * for initializing listContainer.
	 */
	protected void doInitialLayout() {
		listContainer = createPanel();
		listContainer.setLayout(new BetterGridBagLayout());
		this.setLayout(new BorderLayout());
		this.add(listContainer, BorderLayout.NORTH);

		// listContainer.setBackground( Color.blue ); // useful for testing
		// this.setBackground( Color.red );
	}

	/**
	 * Changes the horizontal spacing between the label and the components in the
	 * panel. Note: Assumes listContainer uses a GridBagLayout.
	 * 
	 * @param newHgap the new spacing, in pixels. May not be negative.
	 */
	public void setHgap(int newHgap) {
		if (newHgap < 0)
			return; // may not be negative
		this.hgap = newHgap;
		updateGaps();
		this.revalidate();
		this.repaint();

	}

	/**
	 * Gets the current horizontal spacing between components.
	 * 
	 * @return the current horizontal spacing, in pixels.
	 */
	public int getHgap() {
		return this.hgap;
	}

	/**
	 * Changes the vertical spacing between components in the panel. Note: Assumes
	 * listContainer uses a GridBagLayout.
	 * 
	 * @param newVgap the new spacing, in pixels. May not be negative.
	 */
	public void setVgap(int newVgap) {
		if (newVgap < 0)
			return; // may not be negative
		this.vgap = newVgap;
		updateGaps();
		this.revalidate();
		this.repaint();

	}

	/**
	 * Gets the current vertical spacing between components.
	 * 
	 * @return the current vertical spacing, in pixels.
	 */
	public int getVgap() {
		return this.vgap;
	}

	/**
	 * Sets the minimum width for the labels column. This left margin will grow if
	 * one of the labels is wider than this value. Note: assumes GridBagLayout.
	 * 
	 * @param newMargin the new minimum margin in pixels. May not be negative.
	 */
	public void setMargin(int newMargin) {
		if (newMargin < 0)
			return; // may not be negative
		this.margin = newMargin;

		if (listContainer.getLayout() instanceof GridBagLayout) {
			GridBagLayout gridBag = (GridBagLayout) listContainer.getLayout();
			GridBagConstraints constraints = null;
			Component c = null;
			int count = listContainer.getComponentCount();
			for (int i = 0; i < count; i++) {
				c = listContainer.getComponent(i);
				constraints = gridBag.getConstraints(c);
				if (constraints.gridy == 0 && constraints.gridx % 2 == 0) { // if this is a label spacer
																			// replace it with an appropriately sized
																			// box
					listContainer.remove(c);
					listContainer.add(Box.createHorizontalStrut(this.margin), constraints);
				}
			}
		}

		this.revalidate();
		this.repaint();

	}

	/**
	 * Gets the current minimum margin for the labels column.
	 * 
	 * @return the current minimum margin in pixels.
	 */
	public int getMargin() {
		return this.margin;
	}

	/**
	 * Sets the number of columns for the panel. Label/Component pairs will start
	 * from the top left and fill in to the right before wrapping to the next row.
	 * The default number of columns is one. Note: assumes GridBagLayout.
	 * 
	 * @param newColumns the new number of columns. May not be less than one.
	 */
	public void setColumns(int newColumns) {
		if (newColumns < 1)
			return; // may not be less than one.
		int oldColumns = this.columns;
		this.columns = newColumns;

		if (listContainer.getLayout() instanceof GridBagLayout) {
			GridBagLayout gridBag = (GridBagLayout) listContainer.getLayout();
			int count = listContainer.getComponentCount();
			Component[] components = listContainer.getComponents();
			GridBagConstraints[] constraints = new GridBagConstraints[components.length];
			for (int i = 0; i < components.length; i++) {
				constraints[i] = gridBag.getConstraints(components[i]);
			}
			listContainer.removeAll();
			for (int i = 0; i < components.length; i++) {
				if (constraints[i].gridy != 0) { // ignore first row which is reserved for spacers.

					// translate component to new position
					// (columns*2 accounts for two grid columns for one "actual" column)
					int index = (constraints[i].gridy - 1) * oldColumns * 2 + constraints[i].gridx;
					constraints[i].gridy = (index / (newColumns * 2)) + 1;
					constraints[i].gridx = index % (newColumns * 2);
					listContainer.add(components[i], constraints[i]);
				}
			}
			createSpacers(); // replace the spacers
			updateGaps();
		}

		this.revalidate();
		this.repaint();

	}

	/**
	 * Sets the vertical weight used for determining how to distribute additional
	 * vertical space in the component.
	 * 
	 * @param aComponent Key that exists in the layout.
	 * @return weighty The weight of the component, or -1.0 if not found.
	 */
	public double getVerticalWeightForKey(String key) {
		Container c = getCompositeComponentForKey(key);
		if (c == null)
			return -1.0;
		if (!(listContainer.getLayout() instanceof GridBagLayout))
			return -1.0;
		GridBagLayout layout = (GridBagLayout) listContainer.getLayout();
		GridBagConstraints gbc = layout.getConstraints(c);
		return gbc.weighty;
	}

	/**
	 * Sets the vertical weight used for determining how to distribute additional
	 * vertical space in the component. By default, all weights are zero, so each
	 * component gets its preferred height. If any weights are specified, then
	 * additional space is allocated to those components proportionately.
	 * 
	 * @param aComponent Key that exists in the layout.
	 * @param weighty    The new weight.
	 */
	public void setVerticalWeightForKey(String key, double weighty) {
		Container c = getCompositeComponentForKey(key);
		if (c == null)
			return;
		if (!(listContainer.getLayout() instanceof GridBagLayout))
			return;
		GridBagLayout layout = (GridBagLayout) listContainer.getLayout();
		GridBagConstraints gbc = layout.getConstraints(c);
		gbc.weighty = weighty;
		layout.setConstraints(c, gbc);
		// handle adding on-the-fly
		updateGaps();
		this.revalidate();
		this.repaint();
	}

	/**
	 * Gets the current number of columns.
	 * 
	 * @return the current number of columns.
	 */
	public int getColumns() {
		return this.columns;
	}

	/**
	 * Appends a label containing a key and the specified component to the bottom of
	 * the panel. Any registered action listeners will receive action events from
	 * the component - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key       A string that will be displayed in a label, preferrably
	 *                  unique.
	 * @param component A component that will be placed next to the label. If null,
	 *                  a blank JPanel will be used.
	 */
	public void addPair(String key, Component component) {
		addRow(key, new Component[] { component });
	}

	/**
	 * Appends a label containing a key and the specified component to the bottom of
	 * the panel. Any registered action listeners will receive action events from
	 * the component - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key       A string that will be displayed in a label, preferrably
	 *                  unique.
	 * @param component A component that will be placed next to the label. If null,
	 *                  a blank JPanel will appear.
	 */
	public void addRow(String key, Component component) {
		addRow(key, new Component[] { component });
	}

	/**
	 * Appends a label containing a key and the specified components to the bottom
	 * of the panel. Any registered action listeners will receive action events from
	 * the component - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key        A string that will be displayed in a label, preferrably
	 *                   unique.
	 * @param components An array of components that will be placed next to the
	 *                   label. Any nulls in the list will be replaced with blank
	 *                   JPanels.
	 */
	public void addRow(String key, Component[] components) {
		addCompositeComponent(key, makeCompositeComponent(key, components));
	}

	/**
	 * Appends a label containing a key and the specified components to the bottom
	 * of the panel. Any registered action listeners will receive action events from
	 * the components - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key    A string that will be displayed in a label, preferrably unique.
	 * @param west   A component that will appear to the left of the other
	 *               components, as wide as its preferred width and as tall as the
	 *               tallest of the other components. A null will be replaced with a
	 *               blank JPanel.
	 * @param center A component that will appear between the other components,
	 *               taking up available space. A null will be replaced with a blank
	 *               JPanel.
	 * @param east   A component that will appear to the right of the other
	 *               components, as wide as its preferred width and as tall as the
	 *               tallest of the other components. A null will be replaced with a
	 *               blank JPanel.
	 */
	public void addRow(String key, Component west, Component center, Component east) {
		addCompositeComponent(key, makeCompositeComponent(key, west, center, east));
	}

	/**
	 * Appends a label containing a key and the specified components to the bottom
	 * of the panel. Any registered action listeners will receive action events from
	 * the components - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key    A string that will be displayed in a label, preferrably unique.
	 * @param west   A component that will appear to the left of the other
	 *               components, as wide as its preferred width and as tall as the
	 *               tallest of the other components. A null will be replaced with a
	 *               blank JPanel.
	 * @param north  A component that will appear above all the other components, as
	 *               tall as its preferred height and as wide as the info panel
	 *               itself.
	 * @param center A component that will appear between the other components,
	 *               taking up available space. A null will be replaced with a blank
	 *               JPanel.
	 * @param south  A component that will appear below all the other components, as
	 *               tall as its preferred height and as wide as the info panel
	 *               itself.
	 * @param east   A component that will appear to the right of the other
	 *               components, as wide as its preferred width and as tall as the
	 *               tallest of the other components. A null will be replaced with a
	 *               blank JPanel.
	 */
	public void addRow(String key, Component west, Component north, Component center, Component south, Component east) {
		addCompositeComponent(key, makeCompositeComponent(key, west, north, center, south, east));
	}

	/**
	 * Produces a container that contains the specified components, using
	 * GridLayout. Nulls are ignored. This implementation returns a JPanel.
	 */
	protected Container makeCompositeComponent(String key, Component[] components) {
		JPanel panel = createPanel();
		if (components.length != 0) {
			panel.setLayout(new GridLayout(1, components.length, hgap, vgap));

			Component c;
			for (int i = 0; i < components.length; i++) {
				c = components[i];
				if (c != null) {
					introspectComponent(c, key);
					panel.add(c);
				}
			}
		}
		return panel;
	}

	/**
	 * Produces a container that contains the specified components, using
	 * BorderLayout. Nulls are ignored. This implementation returns a JPanel.
	 */
	protected Container makeCompositeComponent(String key, Component west, Component center, Component east) {
		JPanel panel = createPanel();
		panel.setLayout(new BorderLayout(hgap, vgap));

		if (west != null) {
			introspectComponent(west, key);
			panel.add(west, BorderLayout.WEST);
		}

		if (center != null) {
			introspectComponent(center, key);
			panel.add(center, BorderLayout.CENTER);
		}

		if (east != null) {
			introspectComponent(east, key);
			panel.add(east, BorderLayout.EAST);
		}

		return panel;
	}

	/**
	 * Produces a container that contains the specified components, using
	 * BorderLayout. Nulls are ignored. This implementation returns a JPanel.
	 */
	protected Container makeCompositeComponent(String key, Component west, Component north, Component center,
			Component south, Component east) {
		JPanel panel = createPanel();
		panel.setLayout(new BorderLayout(hgap, vgap));

		if (west != null) {
			introspectComponent(west, key);
			panel.add(west, BorderLayout.WEST);
		}

		if (north != null) {
			introspectComponent(north, key);
			panel.add(north, BorderLayout.WEST);
		}

		if (center != null) {
			introspectComponent(center, key);
			panel.add(center, BorderLayout.CENTER);
		}

		if (south != null) {
			introspectComponent(south, key);
			panel.add(south, BorderLayout.CENTER);
		}

		if (east != null) {
			introspectComponent(east, key);
			panel.add(east, BorderLayout.EAST);
		}

		return panel;
	}

	/**
	 * Override to return a specific component to be used as a label. This
	 * implementation calls createLabel().
	 */
	protected Component createLabelForKey(String aKey) {
		return createLabel();
	}

	/**
	 * Provided for backwards compatibility, and called by the default
	 * implementation of createLabelForKey. This implementation returns a JLabel.
	 */
	protected JLabel createLabel() {
		return new JLabel();
	}

	/**
	 * Appends a label containing a key and the specified component to the bottom of
	 * the panel. Any registered action listeners will receive action events from
	 * the component - the key corresponding to the component will be used as the
	 * action command.
	 * 
	 * @param key       A string that will be displayed in a label, preferrably
	 *                  unique.
	 * @param component A component that will be placed next to the label. If null,
	 *                  a stock JTextField will be used.
	 */
	protected void addCompositeComponent(String key, Component component) {
		if (key == null) {
			key = "";
		}
		Component label = createLabelForKey(key);
		Component field = component;
		if (field == null) {
			field = new JTextField(15); // default to 15 columns
		}
		field.setName(key); // for association and reference
		label.setName(key); // ditto
		if (label instanceof JLabel) {
			((JLabel) label).setHorizontalAlignment(labelAlign);
			((JLabel) label).setLabelFor(field); // for accessibility
		}
		if ("".equals(key)) {
			setText(label, "");
		} else {
			setText(label, prefix + key + postfix);
		}
		field.setEnabled(this.isEditable); // was: setEditable

		GridBagConstraints gbc = new GridBagConstraints();

		if (listContainer.getComponentCount() == 0) { // we've just initialized or called removeAll
			createSpacers();
		}

		gbc.gridx = (fields.size() % this.columns) * 2;
		gbc.gridy = (fields.size() / this.columns) + 1; // spacer is at index zero
		gbc.weightx = 0.0;
		gbc.weighty = 0.0;
		gbc.anchor = this.labelAnchor;
		gbc.fill = GridBagConstraints.HORIZONTAL;
		listContainer.add(label, gbc);

		gbc.fill = GridBagConstraints.BOTH;
		gbc.gridx = gbc.gridx + 1;
		// FIXME: components default to the labelAnchor - should be different?
		gbc.weightx = 1.0;
		gbc.weighty = 0.0;

		listContainer.add(field, gbc);

		if (key.equals(HIDDEN)) { // these components are not to be shown
			setText(label, "     ");
			field.setVisible(false);
		}

		fields.add(field); // using list not map to allow for duplicate keys
		labels.add(label); // ditto

		// handle adding on-the-fly
		updateGaps();
		this.revalidate();
		this.repaint();
	}

	/**
	 * Introspects a component to set the action command and to add the InfoPanel to
	 * its list of ActionListeners.
	 * 
	 * @param aComponent The Component to be introspected.
	 * @param aKey       The action command to be set.
	 */
	protected void introspectComponent(Component aComponent, String aKey) {
		// try to set properties of whatever component this might be
		try {
			Method[] methods = (Method[]) _method_cache.get(aComponent.getClass());
			if (methods == null) {
				Class componentClass = aComponent.getClass();
				BeanInfo info = Introspector.getBeanInfo(componentClass);

				MethodDescriptor[] descriptors = info.getMethodDescriptors();
				Method setMethod = null;
				Method addMethod = null;
				for (int i = 0; ((setMethod == null || addMethod == null) && i < descriptors.length); i++) {
					Method m = descriptors[i].getMethod();
					String name = m.getName();
					if (setMethod == null && name.equals("setActionCommand")) {
						setMethod = m;
					} else if (addMethod == null && name.equals("addActionListener")) {
						addMethod = m;
					}
				}

				methods = new Method[] { setMethod, addMethod };
				_method_cache.put(componentClass, methods);
			}
			if (methods[0] != null) {
				methods[0].invoke(aComponent, new Object[] { aKey });
			}
			if (methods[1] != null) {
				methods[1].invoke(aComponent, new Object[] { this });
				listenedToComponents.add(aComponent);
			}
		} catch (Exception exc) { // error occured while introspecting... move along.
			System.out.println("InfoPanel.introspectComponent: " + exc);
		}
	}

	/**
	 * Called to populate a label component with the specified text. This
	 * implementation attempts to call setText(String) on the component. Override to
	 * customize.
	 */
	protected void setText(Component c, String text) {
		try {
			Method m = c.getClass().getMethod("setText", new Class[] { String.class });
			if (m != null) {
				m.invoke(c, new Object[] { text });
			}
		} catch (Exception exc) {
			// no such method: ignore
		}
	}

	/**
	 * Creates spacer components on the reserved first grid row for each column of
	 * labels and fields. This allows us to set the margin for those label columns,
	 * and set the preferred width of the field columns. A list containing the field
	 * spacers should be assigned to the fieldSpacers instance variable.
	 */
	private void createSpacers() {
		if (listContainer.getLayout() instanceof GridBagLayout) {
			// insert spacers for labels column
			GridBagLayout gridBag = (GridBagLayout) listContainer.getLayout();
			GridBagConstraints constraints = new GridBagConstraints();
			constraints.gridy = 0;
			constraints.fill = GridBagConstraints.HORIZONTAL;

			fieldSpacers = new LinkedList();
			Component fieldSpacer;
			for (int i = 0; i < this.columns; i++) {
				constraints.gridx = i * 2;
				listContainer.add(Box.createHorizontalStrut(this.margin), constraints);

				constraints.gridx = i * 2 + 1;
				fieldSpacer = Box.createHorizontalStrut(0);
				fieldSpacers.add(fieldSpacer);
				listContainer.add(fieldSpacer, constraints);
			}
		}
	}

	/**
	 * Updates the insets for all components.
	 */
	protected void updateGaps() {
		if (listContainer.getLayout() instanceof GridBagLayout) {
			GridBagLayout layout = (GridBagLayout) listContainer.getLayout();
			Component c = null;
			GridBagConstraints gbc = null;
			double totalWeightY = 0.0;
			int count = listContainer.getComponentCount();
			int i;
			for (i = 0; i < count; i++) {
				c = listContainer.getComponent(i);
				gbc = layout.getConstraints(c);
				totalWeightY += gbc.weighty;
				if ((gbc.gridx + 1) % (this.columns * 2) == 0) { // if last component in row
					gbc.insets = new Insets(0, 0, this.vgap, 0);
				} else {
					if (gbc.gridx % 2 == 0) { // is a label column - NOTE: uses eleven pixels before component, per l&f
												// guide
						gbc.insets = new Insets(0, 0, this.vgap, 11);
					} else { // is a component column
						if (gbc.gridy != 0) {
							if (c instanceof JPanel)
								((JPanel) c).setPreferredSize(null);
							gbc.insets = new Insets(0, 0, this.vgap, this.hgap);
						}
					}
				}
				layout.setConstraints(c, gbc);
			}

			// hack: gridbag clumps components in center if weighty is zero
			// if sum of weighty is zero, top-justify the list container
			this.remove(listContainer);
			if (totalWeightY == 0.0) {
				this.add(listContainer, BorderLayout.NORTH);
			} else // put list container in center so it will grow
			{
				this.add(listContainer, BorderLayout.CENTER);
			}
		}
	}

	/**
	 * Updates the label alignment.
	 */
	protected void updateLabels() {
		if (listContainer.getLayout() instanceof GridBagLayout) {
			GridBagLayout layout = (GridBagLayout) listContainer.getLayout();
			Component c = null;
			GridBagConstraints gbc = null;
			Iterator it = labels.iterator();
			while (it.hasNext()) {
				c = (Component) it.next();
				if (c instanceof JLabel) {
					((JLabel) c).setHorizontalAlignment(labelAlign);
				}
				gbc = layout.getConstraints(c);
				gbc.anchor = this.labelAnchor;
				layout.setConstraints(c, gbc);
			}
		}
	}

	/**
	 * Convenience method that uses a stock JTextField.
	 * 
	 * @param key   A string that will be displayed in a label, preferrably unique.
	 * @param value A string that will be displayed in a textfield.
	 */
	public void addPair(String key, String value) {
		addPair(key, value, null);
	}

	/**
	 * Convenience method that uses the specified JTextField or subclass and sets it
	 * to the specified value.
	 * 
	 * @param key       A string that will be displayed in a label, preferrably
	 *                  unique.
	 * @param value     A string that will be displayed in a textfield.
	 * @param textField A JTextField or subclass that will be used to display the
	 *                  value. If null, a stock JTextField will be used.
	 */
	public void addPair(String key, String value, JTextField textField) {
		if (value == null) {
			value = "";
		}
		JTextField field = textField;
		if (field == null) {
			field = new JTextField(15); // default to 15 columns
		} else {
			field = textField;
		}
		field.setText(value);

		addPair(key, (Component) field);
	}

	/**
	 * Removes all components from the list. Buttons, if any, will remain unchanged
	 * - use setButtons( null ) to remove them. NOTE: does not call
	 * super.removeAll().
	 */
	public void removeAll() {
		Object component;
		Method method;
		Class[] paramClasses = new Class[] { ActionListener.class };
		Object[] paramObjects = new Object[] { this };

		Iterator iterator = listenedToComponents.iterator();
		while (iterator.hasNext()) {
			component = iterator.next();
			try {
				method = component.getClass().getMethod("removeActionListener", paramClasses);
				if (method != null) {
					method.invoke(component, paramObjects);
				}
			} catch (Exception exception) {
				// No removeActionListener() method, move along.
			}
		}

		listenedToComponents.clear();

		listContainer.removeAll();
		fields.clear();
		labels.clear();
		this.revalidate();
		this.repaint();

		// FIXME: It is very confusing that this
		// implementation does not call super.removeAll().
	}

	/**
	 * Adds one or buttons to the bottom of the panel with the specified labels from
	 * left to right. Any action listeners will receive action events from clicks on
	 * these buttons - the supplied label will be used as the action command.
	 * 
	 * @param buttons A string array containing the strings to be used for the
	 *                button labels and action commands. A null value will remove
	 *                the button panel.
	 * @see ButtonPanel
	 */
	public void setButtons(String[] buttons) {
		if (buttonPanel == null) {
			buttonPanel = new ButtonPanel();
			buttonPanel.setInsets(new Insets(6, 0, 0, 0));
			// button panel has a 11-pixel top inset
			// and java l&f guide says 17-pixels before command buttons
			buttonPanel.addActionListener(this);
			this.add(buttonPanel, BorderLayout.SOUTH);
		}
		if (buttons == null) {
			this.remove(buttonPanel);
			buttonPanel = null;
		} else {
			buttonPanel.setLabels(buttons);
		}

		this.revalidate();
		this.repaint();
	}

	protected Collection listenedToComponents = new LinkedList();

	/**
	 * Retrieves the names of the buttons that are displayed, if any.
	 * 
	 * @return A string array containing the strings used for the button labels and
	 *         action commands, or null if no buttons have been created.
	 * @see ButtonPanel
	 */
	public String[] getButtons() {
		if (buttonPanel == null) {
			return null; // none created
		}

		return buttonPanel.getLabels();
	}

	/**
	 * Retrieves the actual button panel, if any.
	 * 
	 * @return A button panel, or null if none has been created.
	 * @see ButtonPanel
	 */
	public ButtonPanel getButtonPanel() {
		return buttonPanel;
	}

	/**
	 * Sets whether the values displayed in the panel should be editable. Defaults
	 * to true.
	 * 
	 * @param isEditable Whether the values should be editable.
	 */
	public void setEditable(boolean isEditable) {
		this.isEditable = isEditable;
		Iterator enumeration = fields.iterator();
		while (enumeration.hasNext()) {
			((Component) enumeration.next()).setEnabled(isEditable);
		}
	}

	/**
	 * Gets whether the values displayed in the panel are editable.
	 * 
	 * @return Whether the values should be editable.
	 */
	public boolean isEditable() {
		return this.isEditable;
	}

	/**
	 * Sets the field associated with the key to the specified value. Note: If the
	 * component does not respond to setText() or setString() or setValue() the
	 * value will not be set. JTextFields and the like will work.
	 * 
	 * @param key   A string representing the key associated with the field. Nulls
	 *              are converted to an empty string.
	 * @param value A object to be displayed in the specified field. Nulls are
	 *              converted to an empty string.
	 */
	public void setValueForKey(String key, Object value) {
		setValueForKey(key, value, 0);
	}

	/**
	 * Sets the field associated with the key to the specified value. Note: If the
	 * component does not respond to setText() or setString() or setValue() the
	 * value will not be set. JTextFields and the like will work.
	 * 
	 * @param key   A string representing the key associated with the field. Nulls
	 *              are converted to an empty string.
	 * @param value A object to be displayed in the specified field. Nulls are
	 *              converted to an empty string.
	 */
	public void setValueForKey(String key, Object value, int index) {
		if (key == null) {
			key = "";
		}

		Container field = null;
		for (int i = 0; i < fields.size(); i++) {
			field = (Container) fields.get(i);
			if (key.equals(field.getName())) {
				setValueForIndex(index, i, value);
				return;
			}
		}
		// else not found - ignore
	}

	/**
	 * Sets the first field at the specified row index to the specified value. Note:
	 * If the component does not respond to setText() or setString() or setValue()
	 * the value will not be set. JTextFields and the like will work.
	 * 
	 * @param row   The row index of the component.
	 * @param value A object to be displayed in the specified field. Nulls are
	 *              converted to an empty string.
	 */
	public void setValueForIndex(int row, Object value) {
		setValueForIndex(row, 0, value);
	}

	/**
	 * Sets the field at the specified row index and column index to the specified
	 * value. Note: If the component does not respond to setText() or setString() or
	 * setValue() the value will not be set. JTextFields and the like will work.
	 * 
	 * @param row   The row index of the component.
	 * @param index The column index of the component.
	 * @param value A object to be displayed in the specified field. Nulls are
	 *              converted to an empty string.
	 */
	public void setValueForIndex(int row, int col, Object value) {
		Container field = (Container) fields.get(row);
		Component c = field.getComponent(col);
		setValueForComponent(c, value);
	}

	/**
	 * Sets the value in the field at the specified index. Note: If the component
	 * does not respond to setText() or setString() or setValue() this method will
	 * return null. JTextFields and the like will work.
	 * 
	 * @param A     valid index.
	 * @param value A object to be displayed in the specified field.
	 */
	protected void setValueForComponent(Component aComponent, Object value) {
		// try to set a text or string property
		try {
			BeanInfo info = Introspector.getBeanInfo(aComponent.getClass());
			MethodDescriptor[] methods = info.getMethodDescriptors();
			for (int i = 0; i < methods.length; i++) {
				Method m = methods[i].getMethod();
				Class[] paramTypes = m.getParameterTypes();
				if (paramTypes.length == 1) {
					if (m.getName().equals("setText")) {
						if (paramTypes[0].getName().equals(String.class.getName())) {
							m.invoke(aComponent, new Object[] { value });
						}
					}
					if (m.getName().equals("setString")) {
						if (paramTypes[0].getName().equals(String.class.getName())) {
							m.invoke(aComponent, new Object[] { value });
						}
					}
					if (m.getName().equals("setValue")) {
						if (paramTypes[0].getName().equals(Object.class.getName())) {
							m.invoke(aComponent, new Object[] { value });
						}
					}
				}
			}
		} catch (Exception exc) { // error occured while introspecting... move along.
									// FIXME: should log error in ErrorManager
			System.out.println("InfoPanel.setValueForComponent: " + exc);
		}
	}

	/**
	 * Gets the value in the field at the specified index. Note: If the component
	 * does not respond to getText() or getString() or getSelectedItem() this method
	 * will return null. JTextFields and the like will work.
	 * 
	 * @param A valid index.
	 * @return An object representing the value in the field at the specified index,
	 *         or null if the component does not have a text property or if the
	 *         index is out of bounds.
	 */
	public Object getValueForIndex(int anIndex) {
		return getValueForIndex(anIndex, 0);
	}

	/**
	 * Gets the value in the field at the specified row and column. Note: If the
	 * component does not respond to getText() or getString() or getSelectedItem()
	 * this method will return null. JTextFields and the like will work.
	 * 
	 * @param A valid index.
	 * @return An object representing the value in the field at the specified index,
	 *         or null if the component does not have a text property or if the
	 *         index is out of bounds.
	 */
	public Object getValueForIndex(int row, int col) {
		if ((row >= fields.size()) || (row < 0)) { // out of bounds
			return null;
		}

		Container field = (Container) fields.get(row);
		Component c = field.getComponent(col);
		return getValueForComponent(c);
	}

	/**
	 * Gets the value in the field associated with the key. Note: If the component
	 * does not respond to getText() or getString() or getSelectedItem() this method
	 * will return null. JTextFields and the like will work.
	 * 
	 * @param key An string representing the key associated with the field. Nulls
	 *            are converted to an empty string.
	 * @return An object representing the value in the field associated with the
	 *         key, or null if the key does not exist or if the component does not
	 *         have a text property.
	 */
	public Object getValueForKey(String key) {
		return getValueForKey(key, 0);
	}

	/**
	 * Gets the value in the field associated with the key. Note: If the component
	 * does not respond to getText() or getString() or getSelectedItem() this method
	 * will return null. JTextFields and the like will work.
	 * 
	 * @param key An string representing the key associated with the field. Nulls
	 *            are converted to an empty string.
	 * @return An object representing the value in the field associated with the
	 *         key, or null if the key does not exist or if the component does not
	 *         have a text property.
	 */
	public Object getValueForKey(String key, int index) {
		if (key == null) {
			key = "";
		}

		Container field = null;
		Iterator enumeration = fields.iterator();
		while (enumeration.hasNext()) { // finds first value in list with specified key
			field = (Container) enumeration.next();
			if (key.equals(field.getName())) {
				Component c = field.getComponent(index);
				if (c != null) {
					return getValueForComponent(c);
				}
			}
		}
		// else not found
		return null;
	}

	/**
	 * Gets the value in the specified component. Note: If the component does not
	 * respond to getText() or getString() or getSelectedItem() this method will
	 * return null. JTextFields and the like will work.
	 * 
	 * @param aComponent The specified component.
	 * @return An object representing the value in the component. or null if the
	 *         component does not have a text property.
	 */
	protected Object getValueForComponent(Component aComponent) {
		// try to get a text or string property
		try {
			BeanInfo info = Introspector.getBeanInfo(aComponent.getClass());
			MethodDescriptor[] methods = info.getMethodDescriptors();
			for (int i = 0; i < methods.length; i++) {
				Method m = methods[i].getMethod();
				Class[] paramTypes = m.getParameterTypes();
				if (m.getName().equals("getText")) {
					if (paramTypes.length == 0) {
						return m.invoke(aComponent, new Object[] {});
					}
				}
				if (m.getName().equals("getString")) {
					if (paramTypes.length == 0) {
						return m.invoke(aComponent, new Object[] {});
					}
				}
				if (m.getName().equals("getSelectedItem")) {
					if (paramTypes.length == 0) {
						return m.invoke(aComponent, new Object[] {});
					}
				}
				// TODO: should also handle variants of setValue()
			}
		} catch (Exception exc) { // error occured while introspecting... move along.
			System.out.println("InfoPanel.getValueFromComponent: " + exc);
		}

		// not found
		return null;
	}

	/**
	 * Gets the component associated with the key as a JTextField, for backwards
	 * compatibility.
	 * 
	 * @param key A string representing the key associated with the component. Nulls
	 *            are converted to an empty string.
	 * @return A JTextField that contains the value associated with the key, or null
	 *         if the key does not exist or if the component is not a JTextField.
	 */
	public JTextField getFieldForKey(String key) {
		Component c = getComponentForKey(key);
		if (c instanceof JTextField) {
			return (JTextField) c;
		}
		return null;
	}

	/**
	 * Gets the component associated with the key. If more than one component is
	 * associated with the key, returns the first such component.
	 * 
	 * @param key A string representing the key associated with the component. Nulls
	 *            are converted to an empty string.
	 * @return A component that contains the value associated with the key, or null
	 *         if the key does not exist.
	 */
	public Component getComponentForKey(String key) {
		return getComponentForKey(key, 0);
	}

	/**
	 * Gets the component associated with the key and index.
	 * 
	 * @param key A string representing the key associated with the component. Nulls
	 *            are converted to an empty string.
	 * @return A component that contains the value associated with the key, or null
	 *         if the key does not exist.
	 */
	public Component getComponentForKey(String key, int index) {
		Container c = getCompositeComponentForKey(key);
		if (c == null)
			return null;
		return c.getComponent(index);
	}

	/**
	 * Gets the component at the specified row. If more than one component exists on
	 * that row, returns the first such component.
	 * 
	 * @return A component or null if the row does not exist.
	 */
	public Object getComponentForIndex(int row) {
		return getComponentForIndex(row, 0);
	}

	/**
	 * Gets the component at the specified row and column.
	 * 
	 * @return A component or null if the index is out of bounds.
	 */
	public Object getComponentForIndex(int row, int col) {
		if ((row > fields.size()) || (row < 0)) { // out of bounds
			return null;
		}

		Container field = (Container) fields.get(row);
		return field.getComponent(col);
	}

	/**
	 * Gets the container associated with the key.
	 * 
	 * @param key A string representing the key associated with the component. Nulls
	 *            are converted to an empty string.
	 * @return A component that contains the value associated with the key, or null
	 *         if the key does not exist.
	 */
	protected Container getCompositeComponentForKey(String key) {
		if (key == null) {
			key = "";
		}

		JPanel field = null;
		Iterator enumeration = fields.iterator();
		while (enumeration.hasNext()) { // finds first value in list with specified key
			field = (JPanel) enumeration.next();
			if (key.equals(field.getName())) {
				return field;
			}
		}

		// else not found
		return null;
	}

	/**
	 * Provided for backwards compatibility: calls getLabelComponentForKey.
	 * 
	 * @param key A string representing the key associated with the compoent. Nulls
	 *            are converted to an empty string.
	 * @return Component label object associated with the key, or null if the key
	 *         does not exist or if the label component is not an instance of
	 *         JLabel.
	 */
	public JLabel getLabelForKey(String key) {
		Component result = getLabelComponentForKey(key);
		if (result instanceof JLabel)
			return (JLabel) result;
		return null;
	}

	/**
	 * Get the label component associated with the key.
	 * 
	 * @param key A string representing the key associated with the compoent. Nulls
	 *            are converted to an empty string.
	 * @return Component label object associated with the key, or null if the key
	 *         does not exist.
	 */
	public Component getLabelComponentForKey(String key) {
		if (key == null) {
			key = "";
		}

		Component label = null;
		Iterator enumeration = labels.iterator();
		while (enumeration.hasNext()) { // finds first value in list with specified key
			label = (Component) enumeration.next();
			if (key.equals(label.getName())) {
				return label;
			}
		}

		// else not found
		return null;
	}

	/**
	 * Replaces the first component associated with the key. Any value in the
	 * existing component will be copied to the new component.
	 * 
	 * @param key A string representing the key to be associated with the component.
	 *            Nulls are converted to an empty string.
	 * @param c   A component to be placed next to the label corresponding to the
	 *            key. Nulls are converted to a JTextField.
	 */
	public void setComponentForKey(String key, Component c) {
		setComponentForKey(key, c, 0);
	}

	/**
	 * Replaces the component associated with the key. Any value in the existing
	 * component will be copied to the new component.
	 * 
	 * @param key A string representing the key to be associated with the component.
	 *            Nulls are converted to an empty string.
	 * @param c   A component to be placed next to the label corresponding to the
	 *            key. Nulls are converted to a JTextField.
	 */
	public void setComponentForKey(String key, Component c, int index) {
		if (c == null) {
			c = new JTextField(15);
		}
		if (key == null) {
			key = "";
		}

		Container container = this.getCompositeComponentForKey(key);
		Component field = container.getComponent(index);
		Object value = this.getValueForKey(key, index);
		if (field != null) {
			container.remove(index);
			container.add(c, index);
			c.setEnabled(this.isEditable);
			introspectComponent(c, key);
			setValueForComponent(c, value);
		}
	}

	/**
	 * Replaces the first component in the specified row. Any value in the existing
	 * component will be copied to the new component.
	 * 
	 * @param row A valid index.
	 * @param c   A component to be placed next to the label corresponding to the
	 *            key.
	 */
	public void setComponentForIndex(int row, Component c) {
		setComponentForIndex(row, 0, c);
	}

	/**
	 * Replaces the component associated with the key. Any value in the existing
	 * component will be copied to the new component.
	 * 
	 * @param row A valid index.
	 * @param c   A component to be placed next to the label corresponding to the
	 *            key.
	 */
	public void setComponentForIndex(int row, int col, Component c) {
		setComponentForKey(getLabels()[row], c, col);
	}

	/**
	 * Sets the string that appears before each label's text on the panel.
	 * 
	 * @param aString A String to be used as the label prefix.
	 */
	public void setLabelPrefix(String aString) {
		prefix = aString;
		setLabels(getLabels()); // force refresh
	}

	/**
	 * Gets the string that appears before each label's text on the panel. Defaults
	 * to "", an empty string.
	 * 
	 * @return A String that is currently used as the label prefix.
	 */
	public String getLabelPrefix() {
		return prefix;
	}

	/**
	 * Sets the string that appears after each label's text on the panel. Defaults
	 * to ": ", a colon followed by a space.
	 * 
	 * @param aString A String to be used as the label postfix.
	 */
	public void setLabelPostfix(String aString) {
		postfix = aString;
		setLabels(getLabels()); // force refresh
	}

	/**
	 * Gets the string that appears after each label's text on the panel.
	 * 
	 * @return A String that is currently used as the label postfix.
	 */
	public String getLabelPostfix() {
		return postfix;
	}

	/**
	 * Adds an action listener to the list that will be notified by events occurring
	 * in the panel.
	 * 
	 * @param l An action listener to be notified.
	 */
	public void addActionListener(ActionListener l) {
		actionListener = AWTEventMulticaster.add(actionListener, l);
	}

	/**
	 * Removes an action listener from the list that will be notified by events
	 * occurring in the panel.
	 * 
	 * @param l An action listener to be removed.
	 */
	public void removeActionListener(ActionListener l) {
		actionListener = AWTEventMulticaster.remove(actionListener, l);
	}

	/**
	 * Notifies all registered action listeners of a pending Action Event.
	 * 
	 * @param e An action event to be broadcast.
	 */
	protected void broadcastEvent(ActionEvent e) {
		if (actionListener != null) {
			actionListener.actionPerformed(e);
		}
	}

	// interface ActionListener

	/**
	 * Called by buttons on panel and by other components that might be set to
	 * broadcast events to this listener. Simply forwards the action event
	 * unchanged.
	 * 
	 * @param e An action event to be received.
	 */
	public void actionPerformed(ActionEvent e) {
//        if ( e.getSource() instanceof AbstractButton )
//        {
		broadcastEvent(e);
//        }
	}

	/**
	 * GridBagLayout allocates weightx only after considering the preferred width of
	 * the components in a column. We'd prefer that preferred width wasn't
	 * considered, so that the layout worked more like a html-table. GridBagLayout
	 * is poorly factored for subclassing, so this code is going to get a little bit
	 * ugly. Really, what good is a protected method that returns a private class?
	 * Would have liked to just override getLayoutInfo and be done with it.
	 */
	private class BetterGridBagLayout extends GridBagLayout {
		public Dimension preferredLayoutSize(Container parent) {
			preprocess();
			return super.preferredLayoutSize(parent);
		}

		public Dimension minimumLayoutSize(Container parent) {
			preprocess();
			return super.minimumLayoutSize(parent);
		}

		public void layoutContainer(Container parent) {
			preprocess();
			super.layoutContainer(parent);
		}

		protected void preprocess() {
			if (fieldSpacers == null)
				return;
			Iterator i;

			// find the field with the widest preferred size
			Component c;
			int maxWidth = 0;
			i = fields.iterator();
			while (i.hasNext()) {
				c = (Component) i.next();
				maxWidth = Math.max(maxWidth, Math.max(c.getPreferredSize().width, c.getMinimumSize().width));
			}

			// set each column's spacers to that preferred size
			Dimension min = new Dimension(0, 0);
			Dimension pref = new Dimension(maxWidth, 0);
			i = fieldSpacers.iterator();
			while (i.hasNext()) {
				((Box.Filler) i.next()).changeShape(min, pref, pref);
			}
		}
	}
}