001 /* SizeSequence.java --
002 Copyright (C) 2002, 2006, Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package javax.swing;
039
040 import java.util.Arrays;
041
042 /**
043 * A sequence of values that represent the dimensions (widths or heights) of
044 * some collection of items (for example, the widths of the columns in a table).
045 *
046 * @author Andrew Selkirk
047 */
048 public class SizeSequence
049 {
050 // TODO: Sun's API specification for this class contains an implementation
051 // note regarding the encoding for the element sizes. We currently use the
052 // simple size encoding but we should look at improving this.
053
054 /** Storage for the element sizes. */
055 private int[] sizes;
056
057 /**
058 * Creates a new empty <code>SizeSequence</code> instance.
059 */
060 public SizeSequence()
061 {
062 sizes = new int[0];
063 }
064
065 /**
066 * Creates a new <code>SizeSequence</code> instance with the specified number
067 * of elements, each having a size of 0.
068 *
069 * @param numEntries the number of elements.
070 */
071 public SizeSequence(int numEntries)
072 {
073 this(numEntries, 0);
074 }
075
076 /**
077 * Creates a new <code>SizeSequence</code> instance with the specified number
078 * of elements all having the same size (<code>value</code>).
079 *
080 * @param numEntries the number of elements.
081 * @param value the value for each element.
082 */
083 public SizeSequence(int numEntries, int value)
084 {
085 sizes = new int[numEntries];
086 Arrays.fill(sizes, value);
087 }
088
089 /**
090 * Creates a new <code>SizeSequence</code> instance using the specified
091 * element sizes.
092 *
093 * @param sizes the element sizes (<code>null</code> not permitted).
094 */
095 public SizeSequence(int[] sizes)
096 {
097 this.sizes = (int[]) sizes.clone();
098 }
099
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 }