1 /*
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   9  * by Oracle in the LICENSE file that accompanied this code.
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  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
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  25 
  26 package javax.swing;
  27 
  28 import javax.swing.event.*;
  29 
  30 
  31 /**
  32  * Defines the data model used by components like {@code Slider}s
  33  * and {@code ProgressBar}s.
  34  * Defines four interrelated integer properties: minimum, maximum, extent
  35  * and value.  These four integers define two nested ranges like this:
  36  * <pre>
  37  * minimum &lt;= value &lt;= value+extent &lt;= maximum
  38  * </pre>
  39  * The outer range is {@code minimum,maximum} and the inner
  40  * range is {@code value,value+extent}.  The inner range
  41  * must lie within the outer one, i.e. {@code value} must be
  42  * less than or equal to {@code maximum} and {@code value+extent}
  43  * must greater than or equal to {@code minimum}, and {@code maximum}
  44  * must be greater than or equal to {@code minimum}.
  45  * There are a few features of this model that one might find a little
  46  * surprising.  These quirks exist for the convenience of the
  47  * Swing BoundedRangeModel clients, such as {@code Slider} and
  48  * {@code ScrollBar}.
  49  * <ul>
  50  * <li>
  51  *   The minimum and maximum set methods "correct" the other
  52  *   three properties to accommodate their new value argument.  For
  53  *   example setting the model's minimum may change its maximum, value,
  54  *   and extent properties (in that order), to maintain the constraints
  55  *   specified above.
  56  *
  57  * <li>
  58  *   The value and extent set methods "correct" their argument to
  59  *   fit within the limits defined by the other three properties.
  60  *   For example if {@code value == maximum}, {@code setExtent(10)}
  61  *   would change the extent (back) to zero.
  62  *
  63  * <li>
  64  *   The four BoundedRangeModel values are defined as Java Beans properties
  65  *   however Swing ChangeEvents are used to notify clients of changes rather
  66  *   than PropertyChangeEvents. This was done to keep the overhead of monitoring
  67  *   a BoundedRangeModel low. Changes are often reported at MouseDragged rates.
  68  * </ul>
  69  *
  70  * <p>
  71  *
  72  * For an example of specifying custom bounded range models used by sliders,
  73  * see <a
  74  href="http://www.oracle.com/technetwork/java/architecture-142923.html#separable">Separable model architecture</a>
  75  * in <em>A Swing Architecture Overview.</em>
  76  *
  77  * @author Hans Muller
  78  * @see DefaultBoundedRangeModel
  79  * @since 1.2
  80  */
  81 public interface BoundedRangeModel
  82 {
  83     /**
  84      * Returns the minimum acceptable value.
  85      *
  86      * @return the value of the minimum property
  87      * @see #setMinimum
  88      */
  89     int getMinimum();
  90 
  91 
  92     /**
  93      * Sets the model's minimum to <I>newMinimum</I>.   The
  94      * other three properties may be changed as well, to ensure
  95      * that:
  96      * <pre>
  97      * minimum &lt;= value &lt;= value+extent &lt;= maximum
  98      * </pre>
  99      * <p>
 100      * Notifies any listeners if the model changes.
 101      *
 102      * @param newMinimum the model's new minimum
 103      * @see #getMinimum
 104      * @see #addChangeListener
 105      */
 106     void setMinimum(int newMinimum);
 107 
 108 
 109     /**
 110      * Returns the model's maximum.  Note that the upper
 111      * limit on the model's value is (maximum - extent).
 112      *
 113      * @return the value of the maximum property.
 114      * @see #setMaximum
 115      * @see #setExtent
 116      */
 117     int getMaximum();
 118 
 119 
 120     /**
 121      * Sets the model's maximum to <I>newMaximum</I>. The other
 122      * three properties may be changed as well, to ensure that
 123      * <pre>
 124      * minimum &lt;= value &lt;= value+extent &lt;= maximum
 125      * </pre>
 126      * <p>
 127      * Notifies any listeners if the model changes.
 128      *
 129      * @param newMaximum the model's new maximum
 130      * @see #getMaximum
 131      * @see #addChangeListener
 132      */
 133     void setMaximum(int newMaximum);
 134 
 135 
 136     /**
 137      * Returns the model's current value.  Note that the upper
 138      * limit on the model's value is {@code maximum - extent}
 139      * and the lower limit is {@code minimum}.
 140      *
 141      * @return  the model's value
 142      * @see     #setValue
 143      */
 144     int getValue();
 145 
 146 
 147     /**
 148      * Sets the model's current value to {@code newValue} if {@code newValue}
 149      * satisfies the model's constraints. Those constraints are:
 150      * <pre>
 151      * minimum &lt;= value &lt;= value+extent &lt;= maximum
 152      * </pre>
 153      * Otherwise, if {@code newValue} is less than {@code minimum}
 154      * it's set to {@code minimum}, if its greater than
 155      * {@code maximum} then it's set to {@code maximum}, and
 156      * if it's greater than {@code value+extent} then it's set to
 157      * {@code value+extent}.
 158      * <p>
 159      * When a BoundedRange model is used with a scrollbar the value
 160      * specifies the origin of the scrollbar knob (aka the "thumb" or
 161      * "elevator").  The value usually represents the origin of the
 162      * visible part of the object being scrolled.
 163      * <p>
 164      * Notifies any listeners if the model changes.
 165      *
 166      * @param newValue the model's new value
 167      * @see #getValue
 168      */
 169     void setValue(int newValue);
 170 
 171 
 172     /**
 173      * This attribute indicates that any upcoming changes to the value
 174      * of the model should be considered a single event. This attribute
 175      * will be set to true at the start of a series of changes to the value,
 176      * and will be set to false when the value has finished changing.  Normally
 177      * this allows a listener to only take action when the final value change in
 178      * committed, instead of having to do updates for all intermediate values.
 179      * <p>
 180      * Sliders and scrollbars use this property when a drag is underway.
 181      *
 182      * @param b true if the upcoming changes to the value property are part of a series
 183      */
 184     void setValueIsAdjusting(boolean b);
 185 
 186 
 187     /**
 188      * Returns true if the current changes to the value property are part
 189      * of a series of changes.
 190      *
 191      * @return the valueIsAdjustingProperty.
 192      * @see #setValueIsAdjusting
 193      */
 194     boolean getValueIsAdjusting();
 195 
 196 
 197     /**
 198      * Returns the model's extent, the length of the inner range that
 199      * begins at the model's value.
 200      *
 201      * @return  the value of the model's extent property
 202      * @see     #setExtent
 203      * @see     #setValue
 204      */
 205     int getExtent();
 206 
 207 
 208     /**
 209      * Sets the model's extent.  The <I>newExtent</I> is forced to
 210      * be greater than or equal to zero and less than or equal to
 211      * maximum - value.
 212      * <p>
 213      * When a BoundedRange model is used with a scrollbar the extent
 214      * defines the length of the scrollbar knob (aka the "thumb" or
 215      * "elevator").  The extent usually represents how much of the
 216      * object being scrolled is visible. When used with a slider,
 217      * the extent determines how much the value can "jump", for
 218      * example when the user presses PgUp or PgDn.
 219      * <p>
 220      * Notifies any listeners if the model changes.
 221      *
 222      * @param  newExtent the model's new extent
 223      * @see #getExtent
 224      * @see #setValue
 225      */
 226     void setExtent(int newExtent);
 227 
 228 
 229 
 230     /**
 231      * This method sets all of the model's data with a single method call.
 232      * The method results in a single change event being generated. This is
 233      * convenient when you need to adjust all the model data simultaneously and
 234      * do not want individual change events to occur.
 235      *
 236      * @param value  an int giving the current value
 237      * @param extent an int giving the amount by which the value can "jump"
 238      * @param min    an int giving the minimum value
 239      * @param max    an int giving the maximum value
 240      * @param adjusting a boolean, true if a series of changes are in
 241      *                    progress
 242      *
 243      * @see #setValue
 244      * @see #setExtent
 245      * @see #setMinimum
 246      * @see #setMaximum
 247      * @see #setValueIsAdjusting
 248      */
 249     void setRangeProperties(int value, int extent, int min, int max, boolean adjusting);
 250 
 251 
 252     /**
 253      * Adds a ChangeListener to the model's listener list.
 254      *
 255      * @param x the ChangeListener to add
 256      * @see #removeChangeListener
 257      */
 258     void addChangeListener(ChangeListener x);
 259 
 260 
 261     /**
 262      * Removes a ChangeListener from the model's listener list.
 263      *
 264      * @param x the ChangeListener to remove
 265      * @see #addChangeListener
 266      */
 267     void removeChangeListener(ChangeListener x);
 268 
 269 }