| /* |
| * Copyright (c) 2001, 2005, 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 javax.swing; |
| |
| import java.awt.Component; |
| |
| /** |
| * An instance of the <code>Spring</code> class holds three properties that |
| * characterize its behavior: the <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values. Each of these properties may be involved in |
| * defining its fourth, <em>value</em>, property based on a series of rules. |
| * <p> |
| * An instance of the <code>Spring</code> class can be visualized as a |
| * mechanical spring that provides a corrective force as the spring is compressed |
| * or stretched away from its preferred value. This force is modelled |
| * as linear function of the distance from the preferred value, but with |
| * two different constants -- one for the compressional force and one for the |
| * tensional one. Those constants are specified by the minimum and maximum |
| * values of the spring such that a spring at its minimum value produces an |
| * equal and opposite force to that which is created when it is at its |
| * maximum value. The difference between the <em>preferred</em> and |
| * <em>minimum</em> values, therefore, represents the ease with which the |
| * spring can be compressed and the difference between its <em>maximum</em> |
| * and <em>preferred</em> values, indicates the ease with which the |
| * <code>Spring</code> can be extended. |
| * See the {@link #sum} method for details. |
| * |
| * <p> |
| * By defining simple arithmetic operations on <code>Spring</code>s, |
| * the behavior of a collection of <code>Spring</code>s |
| * can be reduced to that of an ordinary (non-compound) <code>Spring</code>. We define |
| * the "+", "-", <em>max</em>, and <em>min</em> operators on |
| * <code>Spring</code>s so that, in each case, the result is a <code>Spring</code> |
| * whose characteristics bear a useful mathematical relationship to its constituent |
| * springs. |
| * |
| * <p> |
| * A <code>Spring</code> can be treated as a pair of intervals |
| * with a single common point: the preferred value. |
| * The following rules define some of the |
| * arithmetic operators that can be applied to intervals |
| * (<code>[a, b]</code> refers to the interval |
| * from <code>a</code> |
| * to <code>b</code>, |
| * where <code>a <= b</code>). |
| * <p> |
| * <pre> |
| * [a1, b1] + [a2, b2] = [a1 + a2, b1 + b2] |
| * |
| * -[a, b] = [-b, -a] |
| * |
| * max([a1, b1], [a2, b2]) = [max(a1, a2), max(b1, b2)] |
| * </pre> |
| * <p> |
| * |
| * If we denote <code>Spring</code>s as <code>[a, b, c]</code>, |
| * where <code>a <= b <= c</code>, we can define the same |
| * arithmetic operators on <code>Spring</code>s: |
| * <p> |
| * <pre> |
| * [a1, b1, c1] + [a2, b2, c2] = [a1 + a2, b1 + b2, c1 + c2] |
| * |
| * -[a, b, c] = [-c, -b, -a] |
| * |
| * max([a1, b1, c1], [a2, b2, c2]) = [max(a1, a2), max(b1, b2), max(c1, c2)] |
| * </pre> |
| * <p> |
| * With both intervals and <code>Spring</code>s we can define "-" and <em>min</em> |
| * in terms of negation: |
| * <p> |
| * <pre> |
| * X - Y = X + (-Y) |
| * |
| * min(X, Y) = -max(-X, -Y) |
| * </pre> |
| * <p> |
| * For the static methods in this class that embody the arithmetic |
| * operators, we do not actually perform the operation in question as |
| * that would snapshot the values of the properties of the method's arguments |
| * at the time the static method is called. Instead, the static methods |
| * create a new <code>Spring</code> instance containing references to |
| * the method's arguments so that the characteristics of the new spring track the |
| * potentially changing characteristics of the springs from which it |
| * was made. This is a little like the idea of a <em>lazy value</em> |
| * in a functional language. |
| * <p> |
| * If you are implementing a <code>SpringLayout</code> you |
| * can find further information and examples in |
| * <a |
| href="http://java.sun.com/docs/books/tutorial/uiswing/layout/spring.html">How to Use SpringLayout</a>, |
| * a section in <em>The Java Tutorial.</em> |
| * <p> |
| * <strong>Warning:</strong> |
| * Serialized objects of this class will not be compatible with |
| * future Swing releases. The current serialization support is |
| * appropriate for short term storage or RMI between applications running |
| * the same version of Swing. As of 1.4, support for long term storage |
| * of all JavaBeans<sup><font size="-2">TM</font></sup> |
| * has been added to the <code>java.beans</code> package. |
| * Please see {@link java.beans.XMLEncoder}. |
| * |
| * @see SpringLayout |
| * @see SpringLayout.Constraints |
| * |
| * @author Philip Milne |
| * @since 1.4 |
| */ |
| public abstract class Spring { |
| |
| /** |
| * An integer value signifying that a property value has not yet been calculated. |
| */ |
| public static final int UNSET = Integer.MIN_VALUE; |
| |
| /** |
| * Used by factory methods to create a <code>Spring</code>. |
| * |
| * @see #constant(int) |
| * @see #constant(int, int, int) |
| * @see #max |
| * @see #minus |
| * @see #sum |
| * @see SpringLayout.Constraints |
| */ |
| protected Spring() {} |
| |
| /** |
| * Returns the <em>minimum</em> value of this <code>Spring</code>. |
| * |
| * @return the <code>minimumValue</code> property of this <code>Spring</code> |
| */ |
| public abstract int getMinimumValue(); |
| |
| /** |
| * Returns the <em>preferred</em> value of this <code>Spring</code>. |
| * |
| * @return the <code>preferredValue</code> of this <code>Spring</code> |
| */ |
| public abstract int getPreferredValue(); |
| |
| /** |
| * Returns the <em>maximum</em> value of this <code>Spring</code>. |
| * |
| * @return the <code>maximumValue</code> property of this <code>Spring</code> |
| */ |
| public abstract int getMaximumValue(); |
| |
| /** |
| * Returns the current <em>value</em> of this <code>Spring</code>. |
| * |
| * @return the <code>value</code> property of this <code>Spring</code> |
| * |
| * @see #setValue |
| */ |
| public abstract int getValue(); |
| |
| /** |
| * Sets the current <em>value</em> of this <code>Spring</code> to <code>value</code>. |
| * |
| * @param value the new setting of the <code>value</code> property |
| * |
| * @see #getValue |
| */ |
| public abstract void setValue(int value); |
| |
| private double range(boolean contract) { |
| return contract ? (getPreferredValue() - getMinimumValue()) : |
| (getMaximumValue() - getPreferredValue()); |
| } |
| |
| /*pp*/ double getStrain() { |
| double delta = (getValue() - getPreferredValue()); |
| return delta/range(getValue() < getPreferredValue()); |
| } |
| |
| /*pp*/ void setStrain(double strain) { |
| setValue(getPreferredValue() + (int)(strain * range(strain < 0))); |
| } |
| |
| /*pp*/ boolean isCyclic(SpringLayout l) { |
| return false; |
| } |
| |
| /*pp*/ static abstract class AbstractSpring extends Spring { |
| protected int size = UNSET; |
| |
| public int getValue() { |
| return size != UNSET ? size : getPreferredValue(); |
| } |
| |
| public final void setValue(int size) { |
| if (this.size == size) { |
| return; |
| } |
| if (size == UNSET) { |
| clear(); |
| } else { |
| setNonClearValue(size); |
| } |
| } |
| |
| protected void clear() { |
| size = UNSET; |
| } |
| |
| protected void setNonClearValue(int size) { |
| this.size = size; |
| } |
| } |
| |
| private static class StaticSpring extends AbstractSpring { |
| protected int min; |
| protected int pref; |
| protected int max; |
| |
| public StaticSpring(int pref) { |
| this(pref, pref, pref); |
| } |
| |
| public StaticSpring(int min, int pref, int max) { |
| this.min = min; |
| this.pref = pref; |
| this.max = max; |
| } |
| |
| public String toString() { |
| return "StaticSpring [" + min + ", " + pref + ", " + max + "]"; |
| } |
| |
| public int getMinimumValue() { |
| return min; |
| } |
| |
| public int getPreferredValue() { |
| return pref; |
| } |
| |
| public int getMaximumValue() { |
| return max; |
| } |
| } |
| |
| private static class NegativeSpring extends Spring { |
| private Spring s; |
| |
| public NegativeSpring(Spring s) { |
| this.s = s; |
| } |
| |
| // Note the use of max value rather than minimum value here. |
| // See the opening preamble on arithmetic with springs. |
| |
| public int getMinimumValue() { |
| return -s.getMaximumValue(); |
| } |
| |
| public int getPreferredValue() { |
| return -s.getPreferredValue(); |
| } |
| |
| public int getMaximumValue() { |
| return -s.getMinimumValue(); |
| } |
| |
| public int getValue() { |
| return -s.getValue(); |
| } |
| |
| public void setValue(int size) { |
| // No need to check for UNSET as |
| // Integer.MIN_VALUE == -Integer.MIN_VALUE. |
| s.setValue(-size); |
| } |
| |
| /*pp*/ boolean isCyclic(SpringLayout l) { |
| return s.isCyclic(l); |
| } |
| } |
| |
| private static class ScaleSpring extends Spring { |
| private Spring s; |
| private float factor; |
| |
| private ScaleSpring(Spring s, float factor) { |
| this.s = s; |
| this.factor = factor; |
| } |
| |
| public int getMinimumValue() { |
| return Math.round((factor < 0 ? s.getMaximumValue() : s.getMinimumValue()) * factor); |
| } |
| |
| public int getPreferredValue() { |
| return Math.round(s.getPreferredValue() * factor); |
| } |
| |
| public int getMaximumValue() { |
| return Math.round((factor < 0 ? s.getMinimumValue() : s.getMaximumValue()) * factor); |
| } |
| |
| public int getValue() { |
| return Math.round(s.getValue() * factor); |
| } |
| |
| public void setValue(int value) { |
| if (value == UNSET) { |
| s.setValue(UNSET); |
| } else { |
| s.setValue(Math.round(value / factor)); |
| } |
| } |
| |
| /*pp*/ boolean isCyclic(SpringLayout l) { |
| return s.isCyclic(l); |
| } |
| } |
| |
| /*pp*/ static class WidthSpring extends AbstractSpring { |
| /*pp*/ Component c; |
| |
| public WidthSpring(Component c) { |
| this.c = c; |
| } |
| |
| public int getMinimumValue() { |
| return c.getMinimumSize().width; |
| } |
| |
| public int getPreferredValue() { |
| return c.getPreferredSize().width; |
| } |
| |
| public int getMaximumValue() { |
| // We will be doing arithmetic with the results of this call, |
| // so if a returned value is Integer.MAX_VALUE we will get |
| // arithmetic overflow. Truncate such values. |
| return Math.min(Short.MAX_VALUE, c.getMaximumSize().width); |
| } |
| } |
| |
| /*pp*/ static class HeightSpring extends AbstractSpring { |
| /*pp*/ Component c; |
| |
| public HeightSpring(Component c) { |
| this.c = c; |
| } |
| |
| public int getMinimumValue() { |
| return c.getMinimumSize().height; |
| } |
| |
| public int getPreferredValue() { |
| return c.getPreferredSize().height; |
| } |
| |
| public int getMaximumValue() { |
| return Math.min(Short.MAX_VALUE, c.getMaximumSize().height); |
| } |
| } |
| |
| /*pp*/ static abstract class SpringMap extends Spring { |
| private Spring s; |
| |
| public SpringMap(Spring s) { |
| this.s = s; |
| } |
| |
| protected abstract int map(int i); |
| |
| protected abstract int inv(int i); |
| |
| public int getMinimumValue() { |
| return map(s.getMinimumValue()); |
| } |
| |
| public int getPreferredValue() { |
| return map(s.getPreferredValue()); |
| } |
| |
| public int getMaximumValue() { |
| return Math.min(Short.MAX_VALUE, map(s.getMaximumValue())); |
| } |
| |
| public int getValue() { |
| return map(s.getValue()); |
| } |
| |
| public void setValue(int value) { |
| if (value == UNSET) { |
| s.setValue(UNSET); |
| } else { |
| s.setValue(inv(value)); |
| } |
| } |
| |
| /*pp*/ boolean isCyclic(SpringLayout l) { |
| return s.isCyclic(l); |
| } |
| } |
| |
| // Use the instance variables of the StaticSpring superclass to |
| // cache values that have already been calculated. |
| /*pp*/ static abstract class CompoundSpring extends StaticSpring { |
| protected Spring s1; |
| protected Spring s2; |
| |
| public CompoundSpring(Spring s1, Spring s2) { |
| super(UNSET); |
| this.s1 = s1; |
| this.s2 = s2; |
| } |
| |
| public String toString() { |
| return "CompoundSpring of " + s1 + " and " + s2; |
| } |
| |
| protected void clear() { |
| super.clear(); |
| min = pref = max = UNSET; |
| s1.setValue(UNSET); |
| s2.setValue(UNSET); |
| } |
| |
| protected abstract int op(int x, int y); |
| |
| public int getMinimumValue() { |
| if (min == UNSET) { |
| min = op(s1.getMinimumValue(), s2.getMinimumValue()); |
| } |
| return min; |
| } |
| |
| public int getPreferredValue() { |
| if (pref == UNSET) { |
| pref = op(s1.getPreferredValue(), s2.getPreferredValue()); |
| } |
| return pref; |
| } |
| |
| public int getMaximumValue() { |
| if (max == UNSET) { |
| max = op(s1.getMaximumValue(), s2.getMaximumValue()); |
| } |
| return max; |
| } |
| |
| public int getValue() { |
| if (size == UNSET) { |
| size = op(s1.getValue(), s2.getValue()); |
| } |
| return size; |
| } |
| |
| /*pp*/ boolean isCyclic(SpringLayout l) { |
| return l.isCyclic(s1) || l.isCyclic(s2); |
| } |
| }; |
| |
| private static class SumSpring extends CompoundSpring { |
| public SumSpring(Spring s1, Spring s2) { |
| super(s1, s2); |
| } |
| |
| protected int op(int x, int y) { |
| return x + y; |
| } |
| |
| protected void setNonClearValue(int size) { |
| super.setNonClearValue(size); |
| s1.setStrain(this.getStrain()); |
| s2.setValue(size - s1.getValue()); |
| } |
| } |
| |
| private static class MaxSpring extends CompoundSpring { |
| |
| public MaxSpring(Spring s1, Spring s2) { |
| super(s1, s2); |
| } |
| |
| protected int op(int x, int y) { |
| return Math.max(x, y); |
| } |
| |
| protected void setNonClearValue(int size) { |
| super.setNonClearValue(size); |
| s1.setValue(size); |
| s2.setValue(size); |
| } |
| } |
| |
| /** |
| * Returns a strut -- a spring whose <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values each have the value <code>pref</code>. |
| * |
| * @param pref the <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values of the new spring |
| * @return a spring whose <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values each have the value <code>pref</code> |
| * |
| * @see Spring |
| */ |
| public static Spring constant(int pref) { |
| return constant(pref, pref, pref); |
| } |
| |
| /** |
| * Returns a spring whose <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values have the values: <code>min</code>, <code>pref</code>, |
| * and <code>max</code> respectively. |
| * |
| * @param min the <em>minimum</em> value of the new spring |
| * @param pref the <em>preferred</em> value of the new spring |
| * @param max the <em>maximum</em> value of the new spring |
| * @return a spring whose <em>minimum</em>, <em>preferred</em>, and |
| * <em>maximum</em> values have the values: <code>min</code>, <code>pref</code>, |
| * and <code>max</code> respectively |
| * |
| * @see Spring |
| */ |
| public static Spring constant(int min, int pref, int max) { |
| return new StaticSpring(min, pref, max); |
| } |
| |
| |
| /** |
| * Returns <code>-s</code>: a spring running in the opposite direction to <code>s</code>. |
| * |
| * @return <code>-s</code>: a spring running in the opposite direction to <code>s</code> |
| * |
| * @see Spring |
| */ |
| public static Spring minus(Spring s) { |
| return new NegativeSpring(s); |
| } |
| |
| /** |
| * Returns <code>s1+s2</code>: a spring representing <code>s1</code> and <code>s2</code> |
| * in series. In a sum, <code>s3</code>, of two springs, <code>s1</code> and <code>s2</code>, |
| * the <em>strains</em> of <code>s1</code>, <code>s2</code>, and <code>s3</code> are maintained |
| * at the same level (to within the precision implied by their integer <em>value</em>s). |
| * The strain of a spring in compression is: |
| * <pre> |
| * value - pref |
| * ------------ |
| * pref - min |
| * </pre> |
| * and the strain of a spring in tension is: |
| * <pre> |
| * value - pref |
| * ------------ |
| * max - pref |
| * </pre> |
| * When <code>setValue</code> is called on the sum spring, <code>s3</code>, the strain |
| * in <code>s3</code> is calculated using one of the formulas above. Once the strain of |
| * the sum is known, the <em>value</em>s of <code>s1</code> and <code>s2</code> are |
| * then set so that they are have a strain equal to that of the sum. The formulas are |
| * evaluated so as to take rounding errors into account and ensure that the sum of |
| * the <em>value</em>s of <code>s1</code> and <code>s2</code> is exactly equal to |
| * the <em>value</em> of <code>s3</code>. |
| * |
| * @return <code>s1+s2</code>: a spring representing <code>s1</code> and <code>s2</code> in series |
| * |
| * @see Spring |
| */ |
| public static Spring sum(Spring s1, Spring s2) { |
| return new SumSpring(s1, s2); |
| } |
| |
| /** |
| * Returns <code>max(s1, s2)</code>: a spring whose value is always greater than (or equal to) |
| * the values of both <code>s1</code> and <code>s2</code>. |
| * |
| * @return <code>max(s1, s2)</code>: a spring whose value is always greater than (or equal to) |
| * the values of both <code>s1</code> and <code>s2</code> |
| * @see Spring |
| */ |
| public static Spring max(Spring s1, Spring s2) { |
| return new MaxSpring(s1, s2); |
| } |
| |
| // Remove these, they're not used often and can be created using minus - |
| // as per these implementations. |
| |
| /*pp*/ static Spring difference(Spring s1, Spring s2) { |
| return sum(s1, minus(s2)); |
| } |
| |
| /* |
| public static Spring min(Spring s1, Spring s2) { |
| return minus(max(minus(s1), minus(s2))); |
| } |
| */ |
| |
| /** |
| * Returns a spring whose <em>minimum</em>, <em>preferred</em>, <em>maximum</em> |
| * and <em>value</em> properties are each multiples of the properties of the |
| * argument spring, <code>s</code>. Minimum and maximum properties are |
| * swapped when <code>factor</code> is negative (in accordance with the |
| * rules of interval arithmetic). |
| * <p> |
| * When factor is, for example, 0.5f the result represents 'the mid-point' |
| * of its input - an operation that is useful for centering components in |
| * a container. |
| * |
| * @param s the spring to scale |
| * @param factor amount to scale by. |
| * @return a spring whose properties are those of the input spring <code>s</code> |
| * multiplied by <code>factor</code> |
| * @throws NullPointerException if <code>s</code> is null |
| * @since 1.5 |
| */ |
| public static Spring scale(Spring s, float factor) { |
| checkArg(s); |
| return new ScaleSpring(s, factor); |
| } |
| |
| /** |
| * Returns a spring whose <em>minimum</em>, <em>preferred</em>, <em>maximum</em> |
| * and <em>value</em> properties are defined by the widths of the <em>minimumSize</em>, |
| * <em>preferredSize</em>, <em>maximumSize</em> and <em>size</em> properties |
| * of the supplied component. The returned spring is a 'wrapper' implementation |
| * whose methods call the appropriate size methods of the supplied component. |
| * The minimum, preferred, maximum and value properties of the returned spring |
| * therefore report the current state of the appropriate properties in the |
| * component and track them as they change. |
| * |
| * @param c Component used for calculating size |
| * @return a spring whose properties are defined by the horizontal component |
| * of the component's size methods. |
| * @throws NullPointerException if <code>c</code> is null |
| * @since 1.5 |
| */ |
| public static Spring width(Component c) { |
| checkArg(c); |
| return new WidthSpring(c); |
| } |
| |
| /** |
| * Returns a spring whose <em>minimum</em>, <em>preferred</em>, <em>maximum</em> |
| * and <em>value</em> properties are defined by the heights of the <em>minimumSize</em>, |
| * <em>preferredSize</em>, <em>maximumSize</em> and <em>size</em> properties |
| * of the supplied component. The returned spring is a 'wrapper' implementation |
| * whose methods call the appropriate size methods of the supplied component. |
| * The minimum, preferred, maximum and value properties of the returned spring |
| * therefore report the current state of the appropriate properties in the |
| * component and track them as they change. |
| * |
| * @param c Component used for calculating size |
| * @return a spring whose properties are defined by the vertical component |
| * of the component's size methods. |
| * @throws NullPointerException if <code>c</code> is null |
| * @since 1.5 |
| */ |
| public static Spring height(Component c) { |
| checkArg(c); |
| return new HeightSpring(c); |
| } |
| |
| |
| /** |
| * If <code>s</code> is null, this throws an NullPointerException. |
| */ |
| private static void checkArg(Object s) { |
| if (s == null) { |
| throw new NullPointerException("Argument must not be null"); |
| } |
| } |
| } |