| /* |
| * Copyright (c) 1995, 2014, 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.util.Hashtable; |
| |
| /** |
| * 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 (in the Java 2 platform v1.2), |
| * {@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 an applet laid out using |
| * the {@code BorderLayout} layout manager: |
| * <p> |
| * <img src="doc-files/BorderLayout-1.gif" |
| * alt="Diagram of an applet 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." |
| * style="float:center; margin: 7px 10px;"> |
| * <p> |
| * The code for this applet is as follows: |
| * |
| * <hr><blockquote><pre> |
| * import java.awt.*; |
| * import java.applet.Applet; |
| * |
| * public class buttonDir extends Applet { |
| * public void init() { |
| * setLayout(new BorderLayout()); |
| * add(new Button("North"), BorderLayout.NORTH); |
| * add(new Button("South"), BorderLayout.SOUTH); |
| * add(new Button("East"), BorderLayout.EAST); |
| * add(new Button("West"), BorderLayout.WEST); |
| * add(new Button("Center"), BorderLayout.CENTER); |
| * } |
| * } |
| * </pre></blockquote><hr> |
| * |
| * @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; |
| |
| /* |
| * JDK 1.1 serialVersionUID |
| */ |
| 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) |
| * @exception 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 |
| * @exception 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 constraints the desired absolute position, one of {@code CENTER}, |
| * {@code NORTH}, {@code SOUTH}, |
| * {@code EAST}, {@code WEST} |
| * @param target the {@code Container} used to obtain |
| * the constraint location based on the target |
| * {@code Container}'s component orientation. |
| * @return the component at the given location, or {@code null} if |
| * the location is empty |
| * @exception IllegalArgumentException if the constraint object is |
| * not one of the five specified constants |
| * @exception 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 + "]"; |
| } |
| } |
