ListLayout.java

/*
 * Copyright (c) 2011, Nikolaus Moll
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the name of the jo-widgets.org nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL jo-widgets.org BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package org.jowidgets.impl.layout;

import java.util.HashMap;

import org.jowidgets.api.widgets.IContainer;
import org.jowidgets.api.widgets.IControl;
import org.jowidgets.common.color.IColorConstant;
import org.jowidgets.common.types.Dimension;
import org.jowidgets.common.types.Rectangle;
import org.jowidgets.common.widgets.layout.ILayouter;

public final class ListLayout implements ILayouter {

    private final IContainer container;
    private final HashMap<IControl, Dimension> preferredSizes;
    private Dimension preferredSize;
    private final IColorConstant[] colors;
    private int lastWidth;

    public ListLayout(final IContainer container, final IColorConstant[] backgroundColors) {
        this.container = container;
        this.colors = backgroundColors;
        this.preferredSizes = new HashMap<IControl, Dimension>();
        this.lastWidth = -1;
    }

    @Override
    public void layout() {
        final Rectangle clientArea = container.getClientArea();
        final int x = clientArea.getX();
        int y = clientArea.getY();
        final int width = clientArea.getWidth();

        int groupIndex = 0;

        for (final IControl control : container.getChildren()) {
            final boolean controlVisible = control.isVisible();
            if (!shouldControlBeVisible(control)) {
                if (controlVisible) {
                    control.setVisible(false);
                }
                continue;
            }

            if (!controlVisible) {
                control.setVisible(true);
                if (control instanceof IContainer) {
                    final IContainer c = (IContainer) control;
                    c.layoutBegin();
                    c.layoutEnd();
                }
            }

            final Dimension size = getPreferredSize(control);

            control.setPosition(x, y);
            control.setSize(width, size.getHeight());
            if (lastWidth != width && control instanceof IContainer) {
                final IContainer c = ((IContainer) control);
                c.layoutBegin();
                c.layoutEnd();
            }

            if (size.getHeight() > 0 && colors.length > 0) {
                control.setBackgroundColor(getAttributeColor(groupIndex));
                groupIndex++;
            }

            y = y + size.getHeight();
        }

        lastWidth = width;
    }

    private IColorConstant getAttributeColor(final int index) {
        return colors[index % colors.length];
    }

    @Override
    public Dimension getMinSize() {
        return getPreferredSize();
    }

    @Override
    public Dimension getPreferredSize() {
        if (preferredSize == null) {
            calculateSizes();
        }
        return preferredSize;
    }

    @Override
    public Dimension getMaxSize() {
        return getPreferredSize();
    }

    @Override
    public void invalidate() {
        preferredSizes.clear();
        preferredSize = null;
    }

    private void calculateSizes() {
        //final Rectangle clientArea = container.getClientArea();
        int preferredWidth = 0;
        int preferredHeight = 0;
        for (final IControl control : container.getChildren()) {
            final boolean controlVisible = control.isVisible();
            if (!shouldControlBeVisible(control)) {
                if (controlVisible) {
                    control.setVisible(false);
                }
                continue;
            }

            if (!controlVisible) {
                control.setVisible(true);
            }

            final Dimension size = getPreferredSize(control);
            preferredWidth = Math.max(preferredWidth, size.getWidth());
            preferredHeight = preferredHeight + size.getHeight();
        }
        preferredSize = container.computeDecoratedSize(new Dimension(preferredWidth, preferredHeight));
    }

    private Dimension getPreferredSize(final IControl control) {
        if (!preferredSizes.containsKey(control)) {
            final Dimension size = control.getPreferredSize();
            if (size == null) {
                return new Dimension(0, 0);
            }
            if (size.getHeight() > 0) {
                preferredSizes.put(control, size);
            }
            return size;
        }
        return preferredSizes.get(control);
    }

    private boolean shouldControlBeVisible(final IControl control) {
        if (control.getLayoutConstraints() == null) {
            return true;
        }
        if (control.getLayoutConstraints() instanceof Boolean) {
            final Boolean visible = (Boolean) control.getLayoutConstraints();
            return visible.booleanValue();
        }

        return true;
    }

}