Java tutorial
/******************************************************************************* * Copyright (c) 2008, 2015 Micah Hainline and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * Micah Hainline - initial API and implementation * Stefan Xenos, IBM Corporation - review, javadoc, and extendedMargins(Rectangle) *******************************************************************************/ package org.eclipse.jface.layout; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.layout.RowLayout; import org.eclipse.swt.widgets.Composite; /** * RowLayoutFactory creates and initializes row layouts. There are two ways to * use RowLayoutFactory. Normally, it is used as a shorthand for writing * "new RowLayout()" and initializing a bunch of fields. In this case the main * benefit is a more concise syntax and the ability to create more than one * identical RowLayout from the same factory. Changing a property of the factory * will affect future layouts created by the factory, but has no effect on * layouts that have already been created. * * @since 3.5 */ public final class RowLayoutFactory { /** * Template layout. The factory will create copies of this layout. */ private RowLayout layout; /** * Creates a new RowLayoutFactory that will create copies of the given * layout. * * @param layout * layout to copy */ private RowLayoutFactory(RowLayout layout) { this.layout = layout; } /** * Creates a factory that creates copies of the given layout. * * @param layout * layout to copy * @return a new RowLayoutFactory instance that creates copies of the given * layout */ public static RowLayoutFactory createFrom(RowLayout layout) { return new RowLayoutFactory(copyLayout(layout)); } /** * Creates a copy of the receiver. * * @return a copy of the receiver */ public RowLayoutFactory copy() { return new RowLayoutFactory(create()); } /** * Creates a RowLayoutFactory that creates RowLayouts with the default SWT * values. * * <p> * Initial values are: * </p> * * <ul> * <li>margins(0,0)</li> * <li>extendedMargins(3,3,3,3)</li> * <li>wrap(true)</li> * <li>pack(true)</li> * <li>fill(false)</li> * <li>justify(false)</li> * <li>spacing(3)</li> * </ul> * * @return a RowLayoutFactory that creates RowLayouts as though created with * their default constructor * @see #fillDefaults */ public static RowLayoutFactory swtDefaults() { return new RowLayoutFactory(new RowLayout()); } /** * Creates a RowLayoutFactory that creates RowLayouts with no margins, fill * behavior, and default dialog spacing. * * <p> * Initial values are: * </p> * * <ul> * <li>margins(0,0)</li> * <li>extendedMargins(0,0,0,0)</li> * <li>wrap(true)</li> * <li>pack(true)</li> * <li>fill(false)</li> * <li>justify(false)</li> * <li>spacing(LayoutConstants.getSpacing().x</li> * </ul> * * @return a RowLayoutFactory that creates RowLayouts with no margins * @see #swtDefaults */ public static RowLayoutFactory fillDefaults() { RowLayout layout = new RowLayout(); layout.marginTop = 0; layout.marginBottom = 0; layout.marginLeft = 0; layout.marginRight = 0; layout.spacing = LayoutConstants.getSpacing().x; return new RowLayoutFactory(layout); } /** * Sets the spacing for layouts created with this factory. The spacing is * the distance between items within the layout. * * @param spacing * spacing (pixels) * @return this * @see #margins(Point) * @see #margins(int, int) */ public RowLayoutFactory spacing(int spacing) { layout.spacing = spacing; return this; } /** * Sets the margins for layouts created with this factory. The margins are * the distance between the outer cells and the edge of the layout. * * @param margins * margin size (pixels) * @return this * @see #spacing(int) */ public RowLayoutFactory margins(Point margins) { layout.marginWidth = margins.x; layout.marginHeight = margins.y; return this; } /** * Sets the margins for layouts created with this factory. The margins * specify the number of pixels of horizontal and vertical margin that will * be placed along the left/right and top/bottom edges of the layout. Note * that these margins will be added to the ones specified by * {@link #extendedMargins(int, int, int, int)}. * * @param width * margin width (pixels) * @param height * margin height (pixels) * @return this * @see #spacing(int) */ public RowLayoutFactory margins(int width, int height) { layout.marginWidth = width; layout.marginHeight = height; return this; } /** * Sets the margins for layouts created with this factory. The margins * specify the number of pixels of horizontal and vertical margin that will * be placed along the left, right, top, and bottom edges of the layout. * Note that these margins will be added to the ones specified by * {@link #margins(int, int)}. * * @param left * left margin size (pixels) * @param right * right margin size (pixels) * @param top * top margin size (pixels) * @param bottom * bottom margin size (pixels) * @return this * @see #spacing(int) * * @since 3.3 */ public RowLayoutFactory extendedMargins(int left, int right, int top, int bottom) { layout.marginLeft = left; layout.marginRight = right; layout.marginTop = top; layout.marginBottom = bottom; return this; } /** * Fill specifies whether the controls in a row should be all the same * height for horizontal layouts, or the same width for vertical layouts. * * @param fill * the fill status * @return this */ public RowLayoutFactory fill(boolean fill) { layout.fill = fill; return this; } /** * Justify specifies whether the controls in a row should be fully * justified, with any extra space placed between the controls. * * @param justify * the justify status * @return this */ public RowLayoutFactory justify(boolean justify) { layout.justify = justify; return this; } /** * Pack specifies whether all controls in the layout take their preferred * size. If pack is false, all controls will have the same size which is the * size required to accommodate the largest preferred height and the largest * preferred width of all the controls in the layout. * * @param pack * the pack status * @return this */ public RowLayoutFactory pack(boolean pack) { layout.pack = pack; return this; } /** * Wrap specifies whether a control will be wrapped to the next row if there * is insufficient space on the current row. * * @param wrap * the wrap status * @return this */ public RowLayoutFactory wrap(boolean wrap) { layout.wrap = wrap; return this; } /** * type specifies whether the layout places controls in rows or columns. * * Possible values are: * <ul> * <li>HORIZONTAL: Position the controls horizontally from left to right</li> * <li>VERTICAL: Position the controls vertically from top to bottom</li> * </ul> * * @param type * One of SWT.HORIZONTAL or SWT.VERTICAL * @return this * * @throws IllegalArgumentException * if type is not one of HORIZONTAL or VERTICAL */ public RowLayoutFactory type(int type) { if (type != SWT.HORIZONTAL && type != SWT.VERTICAL) { throw new IllegalArgumentException(); } layout.type = type; return this; } /** * Creates a new RowLayout, and initializes it with values from the factory. * * @return a new initialized RowLayout. * @see #applyTo */ public RowLayout create() { return copyLayout(layout); } /** * Creates a new RowLayout and attaches it to the given composite. Does not * create the rowData of any of the controls in the composite. * * @param c * composite whose layout will be set * @see #create * @see RowLayoutFactory */ public void applyTo(Composite c) { c.setLayout(copyLayout(layout)); } /** * Copies the given RowLayout instance * * @param layout * layout to copy * @return a new RowLayout */ public static RowLayout copyLayout(RowLayout layout) { RowLayout result = new RowLayout(layout.type); result.marginBottom = layout.marginBottom; result.marginTop = layout.marginTop; result.marginLeft = layout.marginLeft; result.marginRight = layout.marginRight; result.marginHeight = layout.marginHeight; result.marginWidth = layout.marginWidth; result.fill = layout.fill; result.justify = layout.justify; result.pack = layout.pack; result.spacing = layout.spacing; result.wrap = layout.wrap; result.type = layout.type; return result; } }