libjava/classpath/javax/swing/SizeSequence.java

   1 /* SizeSequence.java --
   2    Copyright (C) 2002, 2006, Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package javax.swing;
  39
  40 import java.util.Arrays;
  41
  42 /**
  43  * A sequence of values that represent the dimensions (widths or heights) of
  44  * some collection of items (for example, the widths of the columns in a table).
  45  *
  46  * @author      Andrew Selkirk
  47  */
  48 public class SizeSequence
  49 {
  50   // TODO: Sun's API specification for this class contains an implementation
  51   // note regarding the encoding for the element sizes.  We currently use the
  52   // simple size encoding but we should look at improving this.
  53
  54   /** Storage for the element sizes. */
  55   private int[] sizes;
  56
  57   /**
  58    * Creates a new empty <code>SizeSequence</code> instance.
  59    */
  60   public SizeSequence()
  61   {
  62     sizes = new int[0];
  63   }
  64
  65   /**
  66    * Creates a new <code>SizeSequence</code> instance with the specified number
  67    * of elements, each having a size of 0.
  68    *
  69    * @param numEntries  the number of elements.
  70    */
  71   public SizeSequence(int numEntries)
  72   {
  73     this(numEntries, 0);
  74   }
  75
  76   /**
  77    * Creates a new <code>SizeSequence</code> instance with the specified number
  78    * of elements all having the same size (<code>value</code>).
  79    *
  80    * @param numEntries  the number of elements.
  81    * @param value  the value for each element.
  82    */
  83   public SizeSequence(int numEntries, int value)
  84   {
  85     sizes = new int[numEntries];
  86     Arrays.fill(sizes, value);
  87   }
  88
  89   /**
  90    * Creates a new <code>SizeSequence</code> instance using the specified
  91    * element sizes.
  92    *
  93    * @param sizes  the element sizes (<code>null</code> not permitted).
  94    */
  95   public SizeSequence(int[] sizes)
  96   {
  97     this.sizes = (int[]) sizes.clone();
  98   }
  99
 100   /**
 101    * Sets the size of the element at the specified index.
 102    *
 103    * @param index  the index.
 104    * @param size  the size.
 105    */
 106   public void setSize(int index, int size)
 107   {
 108     if (index >= 0 && index < sizes.length)
 109       sizes[index] = size;
 110   }
 111
 112   /**
 113    * Returns the index of the element that contains the specified position.
 114    *
 115    * @param position  the position.
 116    *
 117    * @return The index of the element that contains the specified position.
 118    */
 119   public int getIndex(int position)
 120   {
 121     int i = 0;
 122     int runningTotal = 0;
 123     while (i < sizes.length && position >= runningTotal + sizes[i])
 124       {
 125         runningTotal += sizes[i];
 126         i++;
 127       }
 128     return i;
 129   }
 130
 131   /**
 132    * Returns the size of the specified element, or 0 if the element index is
 133    * outside the defined range.
 134    *
 135    * @param index  the element index.
 136    *
 137    * @return The size of the specified element, or 0 if the element index is
 138    *     outside the defined range.
 139    */
 140   public int getSize(int index)
 141   {
 142     if (index < 0 || index >= sizes.length)
 143       return 0;
 144     return sizes[index];
 145   }
 146
 147   /**
 148    * Sets the sizes for the elements in the sequence.
 149    *
 150    * @param sizes  the element sizes (<code>null</code> not permitted).
 151    */
 152   public void setSizes(int[] sizes)
 153   {
 154     this.sizes = (int[]) sizes.clone();
 155   }
 156
 157   /**
 158    * Returns an array containing the sizes for all the elements in the sequence.
 159    *
 160    * @return The element sizes.
 161    */
 162   public int[] getSizes()
 163   {
 164     return (int[]) sizes.clone();
 165   }
 166
 167   /**
 168    * Returns the position of the specified element.
 169    *
 170    * @param index  the element index.
 171    *
 172    * @return The position.
 173    */
 174   public int getPosition(int index)
 175   {
 176     int position;
 177     int loop;
 178     position = 0;
 179     for (loop = 0; loop < index; loop++)
 180       position += sizes[loop];
 181     return position;
 182
 183   }
 184
 185   /**
 186    * Inserts new entries into the sequence at the <code>start</code> position.
 187    * There are <code>length</code> new entries each having the specified
 188    * <code>value</code>.
 189    *
 190    * @param start  the start element.
 191    * @param length  the number of elements to insert.
 192    * @param value  the size for each of the new elements.
 193    */
 194   public void insertEntries(int start, int length, int value)
 195   {
 196     int[] newSizes = new int[sizes.length + length];
 197     System.arraycopy(sizes, 0, newSizes, 0, start);
 198     for (int i = start; i < start + length; i++)
 199       newSizes[i] = value;
 200     System.arraycopy(sizes, start, newSizes, start + length,
 201                      sizes.length - start);
 202     sizes = newSizes;
 203   }
 204
 205   /**
 206    * Removes the element(s) at index <code>start</code> (the number of elements
 207    * removed is <code>length</code>).
 208    *
 209    * @param start  the index of the first element to remove.
 210    * @param length  the number of elements to remove.
 211    */
 212   public void removeEntries(int start, int length)
 213   {
 214     // Sanity check.
 215     if ((start + length) > sizes.length)
 216       throw new IllegalArgumentException("Specified start/length that "
 217                                          + "is greater than available sizes");
 218
 219     int[] newSizes = new int[sizes.length - length];
 220     System.arraycopy(sizes, 0, newSizes, 0, start);
 221     System.arraycopy(sizes, start + length, newSizes, start,
 222                      sizes.length - start - length);
 223     sizes = newSizes;
 224   }
 225 }