org.mihalis.opal/src/main/java/org/mihalis/opal/heapManager/HeapManager.java

/*******************************************************************************
 * Copyright (c) 2011 Laurent CARON
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Laurent CARON (laurent.caron at gmail dot com) - Initial implementation and API
 *******************************************************************************/
package org.mihalis.opal.heapManager;

import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Widget;
import org.mihalis.opal.utils.ResourceManager;
import org.mihalis.opal.utils.SWTGraphicUtil;

/**
 * Instances of this class are controls that display the memory used, the whole
 * memory, and contains a button to perform a GC.
 */
public class HeapManager extends Composite {
	
	/** The bar. */
	private Canvas bar;
	
	/** The button. */
	private Button button;
	
	/** The heap max size. */
	private int heapMaxSize;
	
	/** The heap size. */
	private int heapSize;
	
	/** The bar border color. */
	private Color barBorderColor;
	
	/** The bar inner color. */
	private Color barInnerColor;
	
	/** The bar text color. */
	private Color barTextColor;
	
	/** The bar gradient color top start. */
	private Color barGradientColorTopStart;
	
	/** The bar gradient color top end. */
	private Color barGradientColorTopEnd;
	
	/** The bar gradient color middle start. */
	private Color barGradientColorMiddleStart;

	/**
	 * Constructs a new instance of this class given its parent and a style
	 * value describing its behavior and appearance.
	 * <p>
	 * The style value is either one of the style constants defined in class
	 * <code>SWT</code> which is applicable to instances of this class, or must
	 * be built by <em>bitwise OR</em>'ing together (that is, using the
	 * <code>int</code> "|" operator) two or more of those <code>SWT</code>
	 * style constants. The class description lists the style constants that are
	 * applicable to the class. Style bits are also inherited from superclasses.
	 * </p>
	 *
	 * @param parent a widget which will be the parent of the new instance
	 *            (cannot be null)
	 * @param style the style of widget to construct
	 * @see Composite#Composite(Composite, int)
	 * @see Widget#getStyle
	 * @exception IllegalArgumentException <ul>
	 *                <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	 *                </ul>
	 * @exception SWTException <ul>
	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	 *                thread that created the parent</li>
	 *                </ul>
	 */
	public HeapManager(final Composite parent, final int style) {
		super(parent, style);
		final GridLayout gridLayout = new GridLayout(2, false);
		gridLayout.horizontalSpacing = gridLayout.verticalSpacing = 0;
		setLayout(gridLayout);

		createBar();
		createButton();
		updateContent();
		createDefaultColors();
	}

	/**
	 * Creates the bar that displays the memory.
	 */
	private void createBar() {
		this.bar = new Canvas(this, SWT.NONE);
		final GridData gd = new GridData(GridData.FILL, GridData.FILL, true, false);
		gd.minimumWidth = 100;
		gd.heightHint = 30;
		this.bar.setLayoutData(gd);
		this.heapMaxSize = (int) (Runtime.getRuntime().maxMemory() / (1024 * 1024));
		this.bar.addPaintListener(new PaintListener() {
			@Override
			public void paintControl(final PaintEvent e) {
				drawBar(e);
			}
		});
	}

	/**
	 * Draw the bar.
	 *
	 * @param e {@link PaintEvent}
	 */
	private void drawBar(final PaintEvent e) {
		final GC gc = e.gc;
		final Rectangle clientArea = this.bar.getClientArea();

		gc.setForeground(this.barBorderColor);
		gc.setBackground(this.barInnerColor);
		gc.fillRectangle(clientArea);
		gc.drawRectangle(clientArea.x, clientArea.y, clientArea.width - 1, clientArea.height - 1);

		final float width = (clientArea.width - 2f) * this.heapSize / this.heapMaxSize;

		gc.setForeground(this.barGradientColorTopStart);
		gc.setBackground(this.barGradientColorTopEnd);
		gc.fillGradientRectangle(clientArea.x + 1, clientArea.y + 1, (int) width, clientArea.height / 2, true);

		gc.setForeground(this.barGradientColorMiddleStart);
		gc.setBackground(this.barBorderColor);
		gc.fillGradientRectangle(clientArea.x + 1, clientArea.height / 2, (int) width, clientArea.height / 2, true);

		final String message = this.heapSize + " " + ResourceManager.getLabel(ResourceManager.MEGABYTES) + "/" + //
				this.heapMaxSize + " " + ResourceManager.getLabel(ResourceManager.MEGABYTES);
		final Point size = gc.stringExtent(message);

		gc.setForeground(this.barTextColor);
		gc.setFont(getFont());
		gc.drawText(message, (clientArea.width - size.x) / 2, (clientArea.height - size.y) / 2, true);

		gc.dispose();

	}

	/**
	 * Create the button used to perform GC.
	 */
	private void createButton() {
		this.button = new Button(this, SWT.PUSH);
		final Image image = SWTGraphicUtil.createImageFromFile("images/trash.png");
		this.button.setImage(image);
		SWTGraphicUtil.addDisposer(this.button, image);
		this.button.setLayoutData(new GridData(GridData.FILL, GridData.FILL, false, false));
		this.button.addSelectionListener(new SelectionAdapter() {
			/**
			 * @see org.eclipse.swt.events.SelectionAdapter#widgetSelected(org.eclipse.swt.events.SelectionEvent)
			 */
			@Override
			public void widgetSelected(final SelectionEvent e) {
				// SONAR is not amused about self initiated garbage collector calls!
//				System.gc();
			}
		});
		this.button.setToolTipText(ResourceManager.getLabel(ResourceManager.PERFORM_GC));
		this.button.pack();
	}

	/**
	 * Update the content of the bar.
	 */
	private void updateContent() {
		getDisplay().timerExec(500, new Runnable() {
			@Override
			public void run() {
				HeapManager.this.heapSize = (int) (Runtime.getRuntime().totalMemory() / (1024 * 1024));
				if (!isDisposed()) {
					HeapManager.this.bar.redraw();
					if (!getDisplay().isDisposed()) {
						getDisplay().timerExec(500, this);
					}
				}
			}
		});
	}

	/**
	 * Creates the default colors.
	 */
	private void createDefaultColors() {
		this.barTextColor = SWTGraphicUtil.getDefaultColor(this, 57, 98, 149);
		this.barInnerColor = SWTGraphicUtil.getDefaultColor(this, 219, 230, 243);
		this.barBorderColor = SWTGraphicUtil.getDefaultColor(this, 101, 148, 207);
		this.barGradientColorTopStart = SWTGraphicUtil.getDefaultColor(this, 175, 202, 237);
		this.barGradientColorTopEnd = SWTGraphicUtil.getDefaultColor(this, 136, 177, 229);
		this.barGradientColorMiddleStart = SWTGraphicUtil.getDefaultColor(this, 112, 161, 223);
	}

	/**
	 * Gets the bar border color.
	 *
	 * @return the barBorderColor
	 */
	public Color getBarBorderColor() {
		return this.barBorderColor;
	}

	/**
	 * Sets the bar border color.
	 *
	 * @param barBorderColor the barBorderColor to set
	 */
	public void setBarBorderColor(final Color barBorderColor) {
		this.barBorderColor = barBorderColor;
	}

	/**
	 * Gets the bar inner color.
	 *
	 * @return the barInnerColor
	 */
	public Color getBarInnerColor() {
		return this.barInnerColor;
	}

	/**
	 * Sets the bar inner color.
	 *
	 * @param barInnerColor the barInnerColor to set
	 */
	public void setBarInnerColor(final Color barInnerColor) {
		this.barInnerColor = barInnerColor;
	}

	/**
	 * Gets the bar text color.
	 *
	 * @return the barTextColor
	 */
	public Color getBarTextColor() {
		return this.barTextColor;
	}

	/**
	 * Sets the bar text color.
	 *
	 * @param barTextColor the barTextColor to set
	 */
	public void setBarTextColor(final Color barTextColor) {
		this.barTextColor = barTextColor;
	}

	/**
	 * Gets the bar gradient color top start.
	 *
	 * @return the barGradientColorTopStart
	 */
	public Color getBarGradientColorTopStart() {
		return this.barGradientColorTopStart;
	}

	/**
	 * Sets the bar gradient color top start.
	 *
	 * @param barGradientColorTopStart the barGradientColorTopStart to set
	 */
	public void setBarGradientColorTopStart(final Color barGradientColorTopStart) {
		this.barGradientColorTopStart = barGradientColorTopStart;
	}

	/**
	 * Gets the bar gradient color top end.
	 *
	 * @return the barGradientColorTopEnd
	 */
	public Color getBarGradientColorTopEnd() {
		return this.barGradientColorTopEnd;
	}

	/**
	 * Sets the bar gradient color top end.
	 *
	 * @param barGradientColorTopEnd the barGradientColorTopEnd to set
	 */
	public void setBarGradientColorTopEnd(final Color barGradientColorTopEnd) {
		this.barGradientColorTopEnd = barGradientColorTopEnd;
	}

	/**
	 * Gets the bar gradient color middle start.
	 *
	 * @return the barGradientColorMiddleStart
	 */
	public Color getBarGradientColorMiddleStart() {
		return this.barGradientColorMiddleStart;
	}

	/**
	 * Sets the bar gradient color middle start.
	 *
	 * @param barGradientColorMiddleStart the barGradientColorMiddleStart to set
	 */
	public void setBarGradientColorMiddleStart(final Color barGradientColorMiddleStart) {
		this.barGradientColorMiddleStart = barGradientColorMiddleStart;
	}

}