| /* | |
| * Copyright (c) 1995, 2025, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| * | |
| * This code is free software; you can redistribute it and/or modify it | |
| * under the terms of the GNU General Public License version 2 only, as | |
| * published by the Free Software Foundation. Oracle designates this | |
| * particular file as subject to the "Classpath" exception as provided | |
| * by Oracle in the LICENSE file that accompanied this code. | |
| * | |
| * This code 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 General Public License | |
| * version 2 for more details (a copy is included in the LICENSE file that | |
| * accompanied this code). | |
| * | |
| * You should have received a copy of the GNU General Public License version | |
| * 2 along with this work; if not, write to the Free Software Foundation, | |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| * | |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| * or visit www.oracle.com if you need additional information or have any | |
| * questions. | |
| */ | |
| package java.awt; | |
| import java.io.Serial; | |
| /** | |
| * A border layout lays out a container, arranging and resizing | |
| * its components to fit in five regions: | |
| * north, south, east, west, and center. | |
| * Each region may contain no more than one component, and | |
| * is identified by a corresponding constant: | |
| * {@code NORTH}, {@code SOUTH}, {@code EAST}, | |
| * {@code WEST}, and {@code CENTER}. When adding a | |
| * component to a container with a border layout, use one of these | |
| * five constants, for example: | |
| * <pre> | |
| * Panel p = new Panel(); | |
| * p.setLayout(new BorderLayout()); | |
| * p.add(new Button("Okay"), BorderLayout.SOUTH); | |
| * </pre> | |
| * As a convenience, {@code BorderLayout} interprets the | |
| * absence of a string specification the same as the constant | |
| * {@code CENTER}: | |
| * <pre> | |
| * Panel p2 = new Panel(); | |
| * p2.setLayout(new BorderLayout()); | |
| * p2.add(new TextArea()); // Same as p.add(new TextArea(), BorderLayout.CENTER); | |
| * </pre> | |
| * <p> | |
| * In addition, {@code BorderLayout} supports the relative | |
| * positioning constants, {@code PAGE_START}, {@code PAGE_END}, | |
| * {@code LINE_START}, and {@code LINE_END}. | |
| * In a container whose {@code ComponentOrientation} is set to | |
| * {@code ComponentOrientation.LEFT_TO_RIGHT}, these constants map to | |
| * {@code NORTH}, {@code SOUTH}, {@code WEST}, and | |
| * {@code EAST}, respectively. | |
| * <p> | |
| * For compatibility with previous releases, {@code BorderLayout} | |
| * also includes the relative positioning constants {@code BEFORE_FIRST_LINE}, | |
| * {@code AFTER_LAST_LINE}, {@code BEFORE_LINE_BEGINS} and | |
| * {@code AFTER_LINE_ENDS}. These are equivalent to | |
| * {@code PAGE_START}, {@code PAGE_END}, {@code LINE_START} | |
| * and {@code LINE_END} respectively. For | |
| * consistency with the relative positioning constants used by other | |
| * components, the latter constants are preferred. | |
| * <p> | |
| * Mixing both absolute and relative positioning constants can lead to | |
| * unpredictable results. If | |
| * you use both types, the relative constants will take precedence. | |
| * For example, if you add components using both the {@code NORTH} | |
| * and {@code PAGE_START} constants in a container whose | |
| * orientation is {@code LEFT_TO_RIGHT}, only the | |
| * {@code PAGE_START} will be laid out. | |
| * <p> | |
| * NOTE: Currently, | |
| * {@code BorderLayout} does not support vertical | |
| * orientations. The {@code isVertical} setting on the container's | |
| * {@code ComponentOrientation} is not respected. | |
| * <p> | |
| * The components are laid out according to their | |
| * preferred sizes and the constraints of the container's size. | |
| * The {@code NORTH} and {@code SOUTH} components may | |
| * be stretched horizontally; the {@code EAST} and | |
| * {@code WEST} components may be stretched vertically; | |
| * the {@code CENTER} component may stretch both horizontally | |
| * and vertically to fill any space left over. | |
| * <p> | |
| * Here is an example of five buttons in a window laid out using | |
| * the {@code BorderLayout} layout manager: | |
| * <p> | |
| * <img src="doc-files/BorderLayout-1.png" alt="Diagram of a window | |
| * demonstrating BorderLayout. Each section of the BorderLayout contains a | |
| * Button corresponding to its position in the layout, one of: North, West, | |
| * Center, East, or South."> | |
| * <p> | |
| * The code for this program is as follows: | |
| * | |
| * {@snippet lang='java': | |
| * import java.awt.BorderLayout; | |
| * import java.awt.Button; | |
| * import java.awt.EventQueue; | |
| * import java.awt.Frame; | |
| * | |
| * public class BorderLayoutExample { | |
| * | |
| * public static void main(String[] args) throws Exception { | |
| * EventQueue.invokeAndWait(() -> { | |
| * Frame frame = new Frame("BorderLayout"); | |
| * frame.setLayout(new BorderLayout()); | |
| * frame.add(new Button("North"), BorderLayout.NORTH); | |
| * frame.add(new Button("South"), BorderLayout.SOUTH); | |
| * frame.add(new Button("East"), BorderLayout.EAST); | |
| * frame.add(new Button("West"), BorderLayout.WEST); | |
| * frame.add(new Button("Center"), BorderLayout.CENTER); | |
| * frame.setSize(300, 300); | |
| * frame.setVisible(true); | |
| * }); | |
| * } | |
| * } | |
| * } | |
| * | |
| * @author Arthur van Hoff | |
| * @see java.awt.Container#add(String, Component) | |
| * @see java.awt.ComponentOrientation | |
| * @since 1.0 | |
| */ | |
| public class BorderLayout implements LayoutManager2, | |
| java.io.Serializable { | |
| /** | |
| * Constructs a border layout with the horizontal gaps | |
| * between components. | |
| * The horizontal gap is specified by {@code hgap}. | |
| * | |
| * @see #getHgap() | |
| * @see #setHgap(int) | |
| * | |
| * @serial | |
| */ | |
| int hgap; | |
| /** | |
| * Constructs a border layout with the vertical gaps | |
| * between components. | |
| * The vertical gap is specified by {@code vgap}. | |
| * | |
| * @see #getVgap() | |
| * @see #setVgap(int) | |
| * @serial | |
| */ | |
| int vgap; | |
| /** | |
| * Constant to specify components location to be the | |
| * north portion of the border layout. | |
| * @serial | |
| * @see #getChild(String, boolean) | |
| * @see #addLayoutComponent | |
| * @see #getLayoutAlignmentX | |
| * @see #getLayoutAlignmentY | |
| * @see #removeLayoutComponent | |
| */ | |
| Component north; | |
| /** | |
| * Constant to specify components location to be the | |
| * west portion of the border layout. | |
| * @serial | |
| * @see #getChild(String, boolean) | |
| * @see #addLayoutComponent | |
| * @see #getLayoutAlignmentX | |
| * @see #getLayoutAlignmentY | |
| * @see #removeLayoutComponent | |
| */ | |
| Component west; | |
| /** | |
| * Constant to specify components location to be the | |
| * east portion of the border layout. | |
| * @serial | |
| * @see #getChild(String, boolean) | |
| * @see #addLayoutComponent | |
| * @see #getLayoutAlignmentX | |
| * @see #getLayoutAlignmentY | |
| * @see #removeLayoutComponent | |
| */ | |
| Component east; | |
| /** | |
| * Constant to specify components location to be the | |
| * south portion of the border layout. | |
| * @serial | |
| * @see #getChild(String, boolean) | |
| * @see #addLayoutComponent | |
| * @see #getLayoutAlignmentX | |
| * @see #getLayoutAlignmentY | |
| * @see #removeLayoutComponent | |
| */ | |
| Component south; | |
| /** | |
| * Constant to specify components location to be the | |
| * center portion of the border layout. | |
| * @serial | |
| * @see #getChild(String, boolean) | |
| * @see #addLayoutComponent | |
| * @see #getLayoutAlignmentX | |
| * @see #getLayoutAlignmentY | |
| * @see #removeLayoutComponent | |
| */ | |
| Component center; | |
| /** | |
| * | |
| * A relative positioning constant, that can be used instead of | |
| * north, south, east, west or center. | |
| * mixing the two types of constants can lead to unpredictable results. If | |
| * you use both types, the relative constants will take precedence. | |
| * For example, if you add components using both the {@code NORTH} | |
| * and {@code BEFORE_FIRST_LINE} constants in a container whose | |
| * orientation is {@code LEFT_TO_RIGHT}, only the | |
| * {@code BEFORE_FIRST_LINE} will be laid out. | |
| * This will be the same for lastLine, firstItem, lastItem. | |
| * @serial | |
| */ | |
| Component firstLine; | |
| /** | |
| * A relative positioning constant, that can be used instead of | |
| * north, south, east, west or center. | |
| * Please read Description for firstLine. | |
| * @serial | |
| */ | |
| Component lastLine; | |
| /** | |
| * A relative positioning constant, that can be used instead of | |
| * north, south, east, west or center. | |
| * Please read Description for firstLine. | |
| * @serial | |
| */ | |
| Component firstItem; | |
| /** | |
| * A relative positioning constant, that can be used instead of | |
| * north, south, east, west or center. | |
| * Please read Description for firstLine. | |
| * @serial | |
| */ | |
| Component lastItem; | |
| /** | |
| * The north layout constraint (top of container). | |
| */ | |
| public static final String NORTH = "North"; | |
| /** | |
| * The south layout constraint (bottom of container). | |
| */ | |
| public static final String SOUTH = "South"; | |
| /** | |
| * The east layout constraint (right side of container). | |
| */ | |
| public static final String EAST = "East"; | |
| /** | |
| * The west layout constraint (left side of container). | |
| */ | |
| public static final String WEST = "West"; | |
| /** | |
| * The center layout constraint (middle of container). | |
| */ | |
| public static final String CENTER = "Center"; | |
| /** | |
| * Synonym for PAGE_START. Exists for compatibility with previous | |
| * versions. PAGE_START is preferred. | |
| * | |
| * @see #PAGE_START | |
| * @since 1.2 | |
| */ | |
| public static final String BEFORE_FIRST_LINE = "First"; | |
| /** | |
| * Synonym for PAGE_END. Exists for compatibility with previous | |
| * versions. PAGE_END is preferred. | |
| * | |
| * @see #PAGE_END | |
| * @since 1.2 | |
| */ | |
| public static final String AFTER_LAST_LINE = "Last"; | |
| /** | |
| * Synonym for LINE_START. Exists for compatibility with previous | |
| * versions. LINE_START is preferred. | |
| * | |
| * @see #LINE_START | |
| * @since 1.2 | |
| */ | |
| public static final String BEFORE_LINE_BEGINS = "Before"; | |
| /** | |
| * Synonym for LINE_END. Exists for compatibility with previous | |
| * versions. LINE_END is preferred. | |
| * | |
| * @see #LINE_END | |
| * @since 1.2 | |
| */ | |
| public static final String AFTER_LINE_ENDS = "After"; | |
| /** | |
| * The component comes before the first line of the layout's content. | |
| * For Western, left-to-right and top-to-bottom orientations, this is | |
| * equivalent to NORTH. | |
| * | |
| * @see java.awt.Component#getComponentOrientation | |
| * @since 1.4 | |
| */ | |
| public static final String PAGE_START = BEFORE_FIRST_LINE; | |
| /** | |
| * The component comes after the last line of the layout's content. | |
| * For Western, left-to-right and top-to-bottom orientations, this is | |
| * equivalent to SOUTH. | |
| * | |
| * @see java.awt.Component#getComponentOrientation | |
| * @since 1.4 | |
| */ | |
| public static final String PAGE_END = AFTER_LAST_LINE; | |
| /** | |
| * The component goes at the beginning of the line direction for the | |
| * layout. For Western, left-to-right and top-to-bottom orientations, | |
| * this is equivalent to WEST. | |
| * | |
| * @see java.awt.Component#getComponentOrientation | |
| * @since 1.4 | |
| */ | |
| public static final String LINE_START = BEFORE_LINE_BEGINS; | |
| /** | |
| * The component goes at the end of the line direction for the | |
| * layout. For Western, left-to-right and top-to-bottom orientations, | |
| * this is equivalent to EAST. | |
| * | |
| * @see java.awt.Component#getComponentOrientation | |
| * @since 1.4 | |
| */ | |
| public static final String LINE_END = AFTER_LINE_ENDS; | |
| /** | |
| * Use serialVersionUID from JDK 1.1 for interoperability. | |
| */ | |
| @Serial | |
| private static final long serialVersionUID = -8658291919501921765L; | |
| /** | |
| * Constructs a new border layout with | |
| * no gaps between components. | |
| */ | |
| public BorderLayout() { | |
| this(0, 0); | |
| } | |
| /** | |
| * Constructs a border layout with the specified gaps | |
| * between components. | |
| * The horizontal gap is specified by {@code hgap} | |
| * and the vertical gap is specified by {@code vgap}. | |
| * @param hgap the horizontal gap. | |
| * @param vgap the vertical gap. | |
| */ | |
| public BorderLayout(int hgap, int vgap) { | |
| this.hgap = hgap; | |
| this.vgap = vgap; | |
| } | |
| /** | |
| * Returns the horizontal gap between components. | |
| * | |
| * @return the horizontal gap between components | |
| * @since 1.1 | |
| */ | |
| public int getHgap() { | |
| return hgap; | |
| } | |
| /** | |
| * Sets the horizontal gap between components. | |
| * | |
| * @param hgap the horizontal gap between components | |
| * @since 1.1 | |
| */ | |
| public void setHgap(int hgap) { | |
| this.hgap = hgap; | |
| } | |
| /** | |
| * Returns the vertical gap between components. | |
| * | |
| * @return the vertical gap between components | |
| * @since 1.1 | |
| */ | |
| public int getVgap() { | |
| return vgap; | |
| } | |
| /** | |
| * Sets the vertical gap between components. | |
| * | |
| * @param vgap the vertical gap between components | |
| * @since 1.1 | |
| */ | |
| public void setVgap(int vgap) { | |
| this.vgap = vgap; | |
| } | |
| /** | |
| * Adds the specified component to the layout, using the specified | |
| * constraint object. For border layouts, the constraint must be | |
| * one of the following constants: {@code NORTH}, | |
| * {@code SOUTH}, {@code EAST}, | |
| * {@code WEST}, or {@code CENTER}. | |
| * <p> | |
| * Most applications do not call this method directly. This method | |
| * is called when a component is added to a container using the | |
| * {@code Container.add} method with the same argument types. | |
| * @param comp the component to be added. | |
| * @param constraints an object that specifies how and where | |
| * the component is added to the layout. | |
| * @see java.awt.Container#add(java.awt.Component, java.lang.Object) | |
| * @throws IllegalArgumentException if the constraint object is not | |
| * a string, or if it not one of the five specified constants. | |
| * @since 1.1 | |
| */ | |
| public void addLayoutComponent(Component comp, Object constraints) { | |
| synchronized (comp.getTreeLock()) { | |
| if ((constraints == null) || (constraints instanceof String)) { | |
| addLayoutComponent((String)constraints, comp); | |
| } else { | |
| throw new IllegalArgumentException("cannot add to layout: constraint must be a string (or null)"); | |
| } | |
| } | |
| } | |
| /** | |
| * @deprecated replaced by {@code addLayoutComponent(Component, Object)}. | |
| */ | |
| @Deprecated | |
| public void addLayoutComponent(String name, Component comp) { | |
| synchronized (comp.getTreeLock()) { | |
| /* Special case: treat null the same as "Center". */ | |
| if (name == null) { | |
| name = "Center"; | |
| } | |
| /* Assign the component to one of the known regions of the layout. | |
| */ | |
| if ("Center".equals(name)) { | |
| center = comp; | |
| } else if ("North".equals(name)) { | |
| north = comp; | |
| } else if ("South".equals(name)) { | |
| south = comp; | |
| } else if ("East".equals(name)) { | |
| east = comp; | |
| } else if ("West".equals(name)) { | |
| west = comp; | |
| } else if (BEFORE_FIRST_LINE.equals(name)) { | |
| firstLine = comp; | |
| } else if (AFTER_LAST_LINE.equals(name)) { | |
| lastLine = comp; | |
| } else if (BEFORE_LINE_BEGINS.equals(name)) { | |
| firstItem = comp; | |
| } else if (AFTER_LINE_ENDS.equals(name)) { | |
| lastItem = comp; | |
| } else { | |
| throw new IllegalArgumentException("cannot add to layout: unknown constraint: " + name); | |
| } | |
| } | |
| } | |
| /** | |
| * Removes the specified component from this border layout. This | |
| * method is called when a container calls its {@code remove} or | |
| * {@code removeAll} methods. Most applications do not call this | |
| * method directly. | |
| * @param comp the component to be removed. | |
| * @see java.awt.Container#remove(java.awt.Component) | |
| * @see java.awt.Container#removeAll() | |
| */ | |
| public void removeLayoutComponent(Component comp) { | |
| synchronized (comp.getTreeLock()) { | |
| if (comp == center) { | |
| center = null; | |
| } else if (comp == north) { | |
| north = null; | |
| } else if (comp == south) { | |
| south = null; | |
| } else if (comp == east) { | |
| east = null; | |
| } else if (comp == west) { | |
| west = null; | |
| } | |
| if (comp == firstLine) { | |
| firstLine = null; | |
| } else if (comp == lastLine) { | |
| lastLine = null; | |
| } else if (comp == firstItem) { | |
| firstItem = null; | |
| } else if (comp == lastItem) { | |
| lastItem = null; | |
| } | |
| } | |
| } | |
| /** | |
| * Gets the component that was added using the given constraint | |
| * | |
| * @param constraints the desired constraint, one of {@code CENTER}, | |
| * {@code NORTH}, {@code SOUTH}, | |
| * {@code WEST}, {@code EAST}, | |
| * {@code PAGE_START}, {@code PAGE_END}, | |
| * {@code LINE_START}, {@code LINE_END} | |
| * @return the component at the given location, or {@code null} if | |
| * the location is empty | |
| * @throws IllegalArgumentException if the constraint object is | |
| * not one of the nine specified constants | |
| * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| * @since 1.5 | |
| */ | |
| public Component getLayoutComponent(Object constraints) { | |
| if (CENTER.equals(constraints)) { | |
| return center; | |
| } else if (NORTH.equals(constraints)) { | |
| return north; | |
| } else if (SOUTH.equals(constraints)) { | |
| return south; | |
| } else if (WEST.equals(constraints)) { | |
| return west; | |
| } else if (EAST.equals(constraints)) { | |
| return east; | |
| } else if (PAGE_START.equals(constraints)) { | |
| return firstLine; | |
| } else if (PAGE_END.equals(constraints)) { | |
| return lastLine; | |
| } else if (LINE_START.equals(constraints)) { | |
| return firstItem; | |
| } else if (LINE_END.equals(constraints)) { | |
| return lastItem; | |
| } else { | |
| throw new IllegalArgumentException("cannot get component: unknown constraint: " + constraints); | |
| } | |
| } | |
| /** | |
| * Returns the component that corresponds to the given constraint location | |
| * based on the target {@code Container}'s component orientation. | |
| * Components added with the relative constraints {@code PAGE_START}, | |
| * {@code PAGE_END}, {@code LINE_START}, and {@code LINE_END} | |
| * take precedence over components added with the explicit constraints | |
| * {@code NORTH}, {@code SOUTH}, {@code WEST}, and {@code EAST}. | |
| * The {@code Container}'s component orientation is used to determine the location of components | |
| * added with {@code LINE_START} and {@code LINE_END}. | |
| * | |
| * @param target the {@code Container} used to obtain | |
| * the constraint location based on the target | |
| * {@code Container}'s component orientation. | |
| * @param constraints the desired absolute position, one of {@code CENTER}, | |
| * {@code NORTH}, {@code SOUTH}, | |
| * {@code EAST}, {@code WEST} | |
| * @return the component at the given location, or {@code null} if | |
| * the location is empty | |
| * @throws IllegalArgumentException if the constraint object is | |
| * not one of the five specified constants | |
| * @throws NullPointerException if the target parameter is null | |
| * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| * @since 1.5 | |
| */ | |
| public Component getLayoutComponent(Container target, Object constraints) { | |
| boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| Component result = null; | |
| if (NORTH.equals(constraints)) { | |
| result = (firstLine != null) ? firstLine : north; | |
| } else if (SOUTH.equals(constraints)) { | |
| result = (lastLine != null) ? lastLine : south; | |
| } else if (WEST.equals(constraints)) { | |
| result = ltr ? firstItem : lastItem; | |
| if (result == null) { | |
| result = west; | |
| } | |
| } else if (EAST.equals(constraints)) { | |
| result = ltr ? lastItem : firstItem; | |
| if (result == null) { | |
| result = east; | |
| } | |
| } else if (CENTER.equals(constraints)) { | |
| result = center; | |
| } else { | |
| throw new IllegalArgumentException("cannot get component: invalid constraint: " + constraints); | |
| } | |
| return result; | |
| } | |
| /** | |
| * Gets the constraints for the specified component | |
| * | |
| * @param comp the component to be queried | |
| * @return the constraint for the specified component, | |
| * or null if component is null or is not present | |
| * in this layout | |
| * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| * @since 1.5 | |
| */ | |
| public Object getConstraints(Component comp) { | |
| //fix for 6242148 : API method java.awt.BorderLayout.getConstraints(null) should return null | |
| if (comp == null){ | |
| return null; | |
| } | |
| if (comp == center) { | |
| return CENTER; | |
| } else if (comp == north) { | |
| return NORTH; | |
| } else if (comp == south) { | |
| return SOUTH; | |
| } else if (comp == west) { | |
| return WEST; | |
| } else if (comp == east) { | |
| return EAST; | |
| } else if (comp == firstLine) { | |
| return PAGE_START; | |
| } else if (comp == lastLine) { | |
| return PAGE_END; | |
| } else if (comp == firstItem) { | |
| return LINE_START; | |
| } else if (comp == lastItem) { | |
| return LINE_END; | |
| } | |
| return null; | |
| } | |
| /** | |
| * Determines the minimum size of the {@code target} container | |
| * using this layout manager. | |
| * <p> | |
| * This method is called when a container calls its | |
| * {@code getMinimumSize} method. Most applications do not call | |
| * this method directly. | |
| * @param target the container in which to do the layout. | |
| * @return the minimum dimensions needed to lay out the subcomponents | |
| * of the specified container. | |
| * @see java.awt.Container | |
| * @see java.awt.BorderLayout#preferredLayoutSize | |
| * @see java.awt.Container#getMinimumSize() | |
| */ | |
| public Dimension minimumLayoutSize(Container target) { | |
| synchronized (target.getTreeLock()) { | |
| Dimension dim = new Dimension(0, 0); | |
| boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| Component c = null; | |
| if ((c=getChild(EAST,ltr)) != null) { | |
| Dimension d = c.getMinimumSize(); | |
| dim.width += d.width + hgap; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(WEST,ltr)) != null) { | |
| Dimension d = c.getMinimumSize(); | |
| dim.width += d.width + hgap; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(CENTER,ltr)) != null) { | |
| Dimension d = c.getMinimumSize(); | |
| dim.width += d.width; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(NORTH,ltr)) != null) { | |
| Dimension d = c.getMinimumSize(); | |
| dim.width = Math.max(d.width, dim.width); | |
| dim.height += d.height + vgap; | |
| } | |
| if ((c=getChild(SOUTH,ltr)) != null) { | |
| Dimension d = c.getMinimumSize(); | |
| dim.width = Math.max(d.width, dim.width); | |
| dim.height += d.height + vgap; | |
| } | |
| Insets insets = target.getInsets(); | |
| dim.width += insets.left + insets.right; | |
| dim.height += insets.top + insets.bottom; | |
| return dim; | |
| } | |
| } | |
| /** | |
| * Determines the preferred size of the {@code target} | |
| * container using this layout manager, based on the components | |
| * in the container. | |
| * <p> | |
| * Most applications do not call this method directly. This method | |
| * is called when a container calls its {@code getPreferredSize} | |
| * method. | |
| * @param target the container in which to do the layout. | |
| * @return the preferred dimensions to lay out the subcomponents | |
| * of the specified container. | |
| * @see java.awt.Container | |
| * @see java.awt.BorderLayout#minimumLayoutSize | |
| * @see java.awt.Container#getPreferredSize() | |
| */ | |
| public Dimension preferredLayoutSize(Container target) { | |
| synchronized (target.getTreeLock()) { | |
| Dimension dim = new Dimension(0, 0); | |
| boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| Component c = null; | |
| if ((c=getChild(EAST,ltr)) != null) { | |
| Dimension d = c.getPreferredSize(); | |
| dim.width += d.width + hgap; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(WEST,ltr)) != null) { | |
| Dimension d = c.getPreferredSize(); | |
| dim.width += d.width + hgap; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(CENTER,ltr)) != null) { | |
| Dimension d = c.getPreferredSize(); | |
| dim.width += d.width; | |
| dim.height = Math.max(d.height, dim.height); | |
| } | |
| if ((c=getChild(NORTH,ltr)) != null) { | |
| Dimension d = c.getPreferredSize(); | |
| dim.width = Math.max(d.width, dim.width); | |
| dim.height += d.height + vgap; | |
| } | |
| if ((c=getChild(SOUTH,ltr)) != null) { | |
| Dimension d = c.getPreferredSize(); | |
| dim.width = Math.max(d.width, dim.width); | |
| dim.height += d.height + vgap; | |
| } | |
| Insets insets = target.getInsets(); | |
| dim.width += insets.left + insets.right; | |
| dim.height += insets.top + insets.bottom; | |
| return dim; | |
| } | |
| } | |
| /** | |
| * Returns the maximum dimensions for this layout given the components | |
| * in the specified target container. | |
| * @param target the component which needs to be laid out | |
| * @see Container | |
| * @see #minimumLayoutSize | |
| * @see #preferredLayoutSize | |
| */ | |
| public Dimension maximumLayoutSize(Container target) { | |
| return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE); | |
| } | |
| /** | |
| * Returns the alignment along the x axis. This specifies how | |
| * the component would like to be aligned relative to other | |
| * components. The value should be a number between 0 and 1 | |
| * where 0 represents alignment along the origin, 1 is aligned | |
| * the furthest away from the origin, 0.5 is centered, etc. | |
| */ | |
| public float getLayoutAlignmentX(Container parent) { | |
| return 0.5f; | |
| } | |
| /** | |
| * Returns the alignment along the y axis. This specifies how | |
| * the component would like to be aligned relative to other | |
| * components. The value should be a number between 0 and 1 | |
| * where 0 represents alignment along the origin, 1 is aligned | |
| * the furthest away from the origin, 0.5 is centered, etc. | |
| */ | |
| public float getLayoutAlignmentY(Container parent) { | |
| return 0.5f; | |
| } | |
| /** | |
| * Invalidates the layout, indicating that if the layout manager | |
| * has cached information it should be discarded. | |
| */ | |
| public void invalidateLayout(Container target) { | |
| } | |
| /** | |
| * Lays out the container argument using this border layout. | |
| * <p> | |
| * This method actually reshapes the components in the specified | |
| * container in order to satisfy the constraints of this | |
| * {@code BorderLayout} object. The {@code NORTH} | |
| * and {@code SOUTH} components, if any, are placed at | |
| * the top and bottom of the container, respectively. The | |
| * {@code WEST} and {@code EAST} components are | |
| * then placed on the left and right, respectively. Finally, | |
| * the {@code CENTER} object is placed in any remaining | |
| * space in the middle. | |
| * <p> | |
| * Most applications do not call this method directly. This method | |
| * is called when a container calls its {@code doLayout} method. | |
| * @param target the container in which to do the layout. | |
| * @see java.awt.Container | |
| * @see java.awt.Container#doLayout() | |
| */ | |
| public void layoutContainer(Container target) { | |
| synchronized (target.getTreeLock()) { | |
| Insets insets = target.getInsets(); | |
| int top = insets.top; | |
| int bottom = target.height - insets.bottom; | |
| int left = insets.left; | |
| int right = target.width - insets.right; | |
| boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| Component c = null; | |
| if ((c=getChild(NORTH,ltr)) != null) { | |
| c.setSize(right - left, c.height); | |
| Dimension d = c.getPreferredSize(); | |
| c.setBounds(left, top, right - left, d.height); | |
| top += d.height + vgap; | |
| } | |
| if ((c=getChild(SOUTH,ltr)) != null) { | |
| c.setSize(right - left, c.height); | |
| Dimension d = c.getPreferredSize(); | |
| c.setBounds(left, bottom - d.height, right - left, d.height); | |
| bottom -= d.height + vgap; | |
| } | |
| if ((c=getChild(EAST,ltr)) != null) { | |
| c.setSize(c.width, bottom - top); | |
| Dimension d = c.getPreferredSize(); | |
| c.setBounds(right - d.width, top, d.width, bottom - top); | |
| right -= d.width + hgap; | |
| } | |
| if ((c=getChild(WEST,ltr)) != null) { | |
| c.setSize(c.width, bottom - top); | |
| Dimension d = c.getPreferredSize(); | |
| c.setBounds(left, top, d.width, bottom - top); | |
| left += d.width + hgap; | |
| } | |
| if ((c=getChild(CENTER,ltr)) != null) { | |
| c.setBounds(left, top, right - left, bottom - top); | |
| } | |
| } | |
| } | |
| /** | |
| * Get the component that corresponds to the given constraint location | |
| * | |
| * @param key The desired absolute position, | |
| * either NORTH, SOUTH, EAST, or WEST. | |
| * @param ltr Is the component line direction left-to-right? | |
| */ | |
| private Component getChild(String key, boolean ltr) { | |
| Component result = null; | |
| if (key == NORTH) { | |
| result = (firstLine != null) ? firstLine : north; | |
| } | |
| else if (key == SOUTH) { | |
| result = (lastLine != null) ? lastLine : south; | |
| } | |
| else if (key == WEST) { | |
| result = ltr ? firstItem : lastItem; | |
| if (result == null) { | |
| result = west; | |
| } | |
| } | |
| else if (key == EAST) { | |
| result = ltr ? lastItem : firstItem; | |
| if (result == null) { | |
| result = east; | |
| } | |
| } | |
| else if (key == CENTER) { | |
| result = center; | |
| } | |
| if (result != null && !result.visible) { | |
| result = null; | |
| } | |
| return result; | |
| } | |
| /** | |
| * Returns a string representation of the state of this border layout. | |
| * @return a string representation of this border layout. | |
| */ | |
| public String toString() { | |
| return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap + "]"; | |
| } | |
| } |