Java tutorial
/* * Copyright (c) 1997, 2013, 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 javax.swing.event.*; /** * Defines the data model used by components like <code>Slider</code>s * and <code>ProgressBar</code>s. * Defines four interrelated integer properties: minimum, maximum, extent * and value. These four integers define two nested ranges like this: * <pre> * minimum <= value <= value+extent <= maximum * </pre> * The outer range is <code>minimum,maximum</code> and the inner * range is <code>value,value+extent</code>. The inner range * must lie within the outer one, i.e. <code>value</code> must be * less than or equal to <code>maximum</code> and <code>value+extent</code> * must greater than or equal to <code>minimum</code>, and <code>maximum</code> * must be greater than or equal to <code>minimum</code>. * There are a few features of this model that one might find a little * surprising. These quirks exist for the convenience of the * Swing BoundedRangeModel clients, such as <code>Slider</code> and * <code>ScrollBar</code>. * <ul> * <li> * The minimum and maximum set methods "correct" the other * three properties to accommodate their new value argument. For * example setting the model's minimum may change its maximum, value, * and extent properties (in that order), to maintain the constraints * specified above. * * <li> * The value and extent set methods "correct" their argument to * fit within the limits defined by the other three properties. * For example if <code>value == maximum</code>, <code>setExtent(10)</code> * would change the extent (back) to zero. * * <li> * The four BoundedRangeModel values are defined as Java Beans properties * however Swing ChangeEvents are used to notify clients of changes rather * than PropertyChangeEvents. This was done to keep the overhead of monitoring * a BoundedRangeModel low. Changes are often reported at MouseDragged rates. * </ul> * * <p> * * For an example of specifying custom bounded range models used by sliders, * see <a href="http://www.oracle.com/technetwork/java/architecture-142923.html#separable">Separable model architecture</a> * in <em>A Swing Architecture Overview.</em> * * @author Hans Muller * @see DefaultBoundedRangeModel * @since 1.2 */ public interface BoundedRangeModel { /** * Returns the minimum acceptable value. * * @return the value of the minimum property * @see #setMinimum */ int getMinimum(); /** * Sets the model's minimum to <I>newMinimum</I>. The * other three properties may be changed as well, to ensure * that: * <pre> * minimum <= value <= value+extent <= maximum * </pre> * <p> * Notifies any listeners if the model changes. * * @param newMinimum the model's new minimum * @see #getMinimum * @see #addChangeListener */ void setMinimum(int newMinimum); /** * Returns the model's maximum. Note that the upper * limit on the model's value is (maximum - extent). * * @return the value of the maximum property. * @see #setMaximum * @see #setExtent */ int getMaximum(); /** * Sets the model's maximum to <I>newMaximum</I>. The other * three properties may be changed as well, to ensure that * <pre> * minimum <= value <= value+extent <= maximum * </pre> * <p> * Notifies any listeners if the model changes. * * @param newMaximum the model's new maximum * @see #getMaximum * @see #addChangeListener */ void setMaximum(int newMaximum); /** * Returns the model's current value. Note that the upper * limit on the model's value is <code>maximum - extent</code> * and the lower limit is <code>minimum</code>. * * @return the model's value * @see #setValue */ int getValue(); /** * Sets the model's current value to <code>newValue</code> if <code>newValue</code> * satisfies the model's constraints. Those constraints are: * <pre> * minimum <= value <= value+extent <= maximum * </pre> * Otherwise, if <code>newValue</code> is less than <code>minimum</code> * it's set to <code>minimum</code>, if its greater than * <code>maximum</code> then it's set to <code>maximum</code>, and * if it's greater than <code>value+extent</code> then it's set to * <code>value+extent</code>. * <p> * When a BoundedRange model is used with a scrollbar the value * specifies the origin of the scrollbar knob (aka the "thumb" or * "elevator"). The value usually represents the origin of the * visible part of the object being scrolled. * <p> * Notifies any listeners if the model changes. * * @param newValue the model's new value * @see #getValue */ void setValue(int newValue); /** * This attribute indicates that any upcoming changes to the value * of the model should be considered a single event. This attribute * will be set to true at the start of a series of changes to the value, * and will be set to false when the value has finished changing. Normally * this allows a listener to only take action when the final value change in * committed, instead of having to do updates for all intermediate values. * <p> * Sliders and scrollbars use this property when a drag is underway. * * @param b true if the upcoming changes to the value property are part of a series */ void setValueIsAdjusting(boolean b); /** * Returns true if the current changes to the value property are part * of a series of changes. * * @return the valueIsAdjustingProperty. * @see #setValueIsAdjusting */ boolean getValueIsAdjusting(); /** * Returns the model's extent, the length of the inner range that * begins at the model's value. * * @return the value of the model's extent property * @see #setExtent * @see #setValue */ int getExtent(); /** * Sets the model's extent. The <I>newExtent</I> is forced to * be greater than or equal to zero and less than or equal to * maximum - value. * <p> * When a BoundedRange model is used with a scrollbar the extent * defines the length of the scrollbar knob (aka the "thumb" or * "elevator"). The extent usually represents how much of the * object being scrolled is visible. When used with a slider, * the extent determines how much the value can "jump", for * example when the user presses PgUp or PgDn. * <p> * Notifies any listeners if the model changes. * * @param newExtent the model's new extent * @see #getExtent * @see #setValue */ void setExtent(int newExtent); /** * This method sets all of the model's data with a single method call. * The method results in a single change event being generated. This is * convenient when you need to adjust all the model data simultaneously and * do not want individual change events to occur. * * @param value an int giving the current value * @param extent an int giving the amount by which the value can "jump" * @param min an int giving the minimum value * @param max an int giving the maximum value * @param adjusting a boolean, true if a series of changes are in * progress * * @see #setValue * @see #setExtent * @see #setMinimum * @see #setMaximum * @see #setValueIsAdjusting */ void setRangeProperties(int value, int extent, int min, int max, boolean adjusting); /** * Adds a ChangeListener to the model's listener list. * * @param x the ChangeListener to add * @see #removeChangeListener */ void addChangeListener(ChangeListener x); /** * Removes a ChangeListener from the model's listener list. * * @param x the ChangeListener to remove * @see #addChangeListener */ void removeChangeListener(ChangeListener x); }