import javax.swing.*;import javax.swing.SpringLayout;import java.awt.*;/** * A 1.4 file that provides utility methods for * creating form- or grid-style layouts with SpringLayout. * These utilities are used by several programs, such as * SpringBox and SpringCompactGrid. */public class SpringUtilities {    /**     * A debugging utility that prints to stdout the component's     * minimum, preferred, and maximum sizes.     */    public static void printSizes(Component c) {        System.out.println("minimumSize = " + c.getMinimumSize());        System.out.println("preferredSize = " + c.getPreferredSize());        System.out.println("maximumSize = " + c.getMaximumSize());    }    /**     * Aligns the first <code>rows</code> * <code>cols</code>     * components of <code>parent</code> in     * a grid. Each component is as big as the maximum     * preferred width and height of the components.     * The parent is made just big enough to fit them all.     *     * @param rows number of rows     * @param cols number of columns     * @param initialX x location to start the grid at     * @param initialY y location to start the grid at     * @param xPad x padding between cells     * @param yPad y padding between cells     */    public static void makeGrid(Container parent,                                int rows, int cols,                                int initialX, int initialY,                                int xPad, int yPad) {        SpringLayout layout;        try {            layout = (SpringLayout)parent.getLayout();        } catch (ClassCastException exc) {            System.err.println("The first argument to makeGrid must use SpringLayout.");            return;        }        Spring xPadSpring = Spring.constant(xPad);        Spring yPadSpring = Spring.constant(yPad);        Spring initialXSpring = Spring.constant(initialX);        Spring initialYSpring = Spring.constant(initialY);        int max = rows * cols;        //Calculate Springs that are the max of the width/height so that all        //cells have the same size.        Spring maxWidthSpring = layout.getConstraints(parent.getComponent(0)).                                    getWidth();        Spring maxHeightSpring = layout.getConstraints(parent.getComponent(0)).                                    getWidth();        for (int i = 1; i < max; i++) {            SpringLayout.Constraints cons = layout.getConstraints(                                            parent.getComponent(i));            maxWidthSpring = Spring.max(maxWidthSpring, cons.getWidth());            maxHeightSpring = Spring.max(maxHeightSpring, cons.getHeight());        }        //Apply the new width/height Spring. This forces all the        //components to have the same size.        for (int i = 0; i < max; i++) {            SpringLayout.Constraints cons = layout.getConstraints(                                            parent.getComponent(i));            cons.setWidth(maxWidthSpring);            cons.setHeight(maxHeightSpring);        }        //Then adjust the x/y constraints of all the cells so that they        //are aligned in a grid.        SpringLayout.Constraints lastCons = null;        SpringLayout.Constraints lastRowCons = null;        for (int i = 0; i < max; i++) {            SpringLayout.Constraints cons = layout.getConstraints(                                                 parent.getComponent(i));            if (i % cols == 0) { //start of new row                lastRowCons = lastCons;                cons.setX(initialXSpring);            } else { //x position depends on previous component                cons.setX(Spring.sum(lastCons.getConstraint(SpringLayout.EAST),                                     xPadSpring));            }            if (i / cols == 0) { //first row                cons.setY(initialYSpring);            } else { //y position depends on previous row                cons.setY(Spring.sum(lastRowCons.getConstraint(SpringLayout.SOUTH),                                     yPadSpring));            }            lastCons = cons;        }        //Set the parent's size.        SpringLayout.Constraints pCons = layout.getConstraints(parent);        pCons.setConstraint(SpringLayout.SOUTH,                            Spring.sum(                                Spring.constant(yPad),                                lastCons.getConstraint(SpringLayout.SOUTH)));        pCons.setConstraint(SpringLayout.EAST,                            Spring.sum(                                Spring.constant(xPad),                                lastCons.getConstraint(SpringLayout.EAST)));    }    /* Used by makeCompactGrid. */    private static SpringLayout.Constraints getConstraintsForCell(                                                int row, int col,                                                Container parent,                                                int cols) {        SpringLayout layout = (SpringLayout) parent.getLayout();        Component c = parent.getComponent(row * cols + col);        return layout.getConstraints(c);    }    /**     * Aligns the first <code>rows</code> * <code>cols</code>     * components of <code>parent</code> in     * a grid. Each component in a column is as wide as the maximum     * preferred width of the components in that column;     * height is similarly determined for each row.     * The parent is made just big enough to fit them all.     *     * @param rows number of rows     * @param cols number of columns     * @param initialX x location to start the grid at     * @param initialY y location to start the grid at     * @param xPad x padding between cells     * @param yPad y padding between cells     */    public static void makeCompactGrid(Container parent,                                       int rows, int cols,                                       int initialX, int initialY,                                       int xPad, int yPad) {        SpringLayout layout;        try {            layout = (SpringLayout)parent.getLayout();        } catch (ClassCastException exc) {            System.err.println("The first argument to makeCompactGrid must use SpringLayout.");            return;        }        //Align all cells in each column and make them the same width.        Spring x = Spring.constant(initialX);        for (int c = 0; c < cols; c++) {            Spring width = Spring.constant(0);            for (int r = 0; r < rows; r++) {                width = Spring.max(width,                                   getConstraintsForCell(r, c, parent, cols).                                       getWidth());            }            for (int r = 0; r < rows; r++) {                SpringLayout.Constraints constraints =                        getConstraintsForCell(r, c, parent, cols);                constraints.setX(x);                constraints.setWidth(width);            }            x = Spring.sum(x, Spring.sum(width, Spring.constant(xPad)));        }        //Align all cells in each row and make them the same height.        Spring y = Spring.constant(initialY);        for (int r = 0; r < rows; r++) {            Spring height = Spring.constant(0);            for (int c = 0; c < cols; c++) {                height = Spring.max(height,                                    getConstraintsForCell(r, c, parent, cols).                                        getHeight());            }            for (int c = 0; c < cols; c++) {                SpringLayout.Constraints constraints =                        getConstraintsForCell(r, c, parent, cols);                constraints.setY(y);                constraints.setHeight(height);            }            y = Spring.sum(y, Spring.sum(height, Spring.constant(yPad)));        }        //Set the parent's size.        SpringLayout.Constraints pCons = layout.getConstraints(parent);        pCons.setConstraint(SpringLayout.SOUTH, y);        pCons.setConstraint(SpringLayout.EAST, x);    }}