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1: /* Segment.java -- 2: Copyright (C) 2002, 2004, 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.text; 39: 40: import java.text.CharacterIterator; 41: 42: /** 43: * A text fragment represented by a sequence of characters stored in an array. 44: */ 45: public class Segment implements Cloneable, CharacterIterator 46: { 47: private boolean partialReturn; 48: 49: /** The current index. */ 50: private int current; 51: 52: /** Storage for the characters (may contain additional characters). */ 53: public char[] array; 54: 55: /** The number of characters in the segment. */ 56: public int count; 57: 58: /** The offset of the first character in the segment. */ 59: public int offset; 60: 61: /** 62: * Creates a new <code>Segment</code>. 63: */ 64: public Segment() 65: { 66: // Nothing to do here. 67: } 68: 69: /** 70: * Creates a new <code>Segment</code>. 71: * 72: * @param array the underlying character data. 73: * @param offset the offset of the first character in the segment. 74: * @param count the number of characters in the segment. 75: */ 76: public Segment(char[] array, int offset, int count) 77: { 78: this.array = array; 79: this.offset = offset; 80: this.count = count; 81: } 82: 83: /** 84: * Clones the segment (note that the underlying character array is not cloned, 85: * just the reference to it). 86: * 87: * @return A clone of the segment. 88: */ 89: public Object clone() 90: { 91: try 92: { 93: return super.clone(); 94: } 95: catch (CloneNotSupportedException e) 96: { 97: return null; 98: } 99: } 100: 101: /** 102: * Returns the character at the current index. If the segment consists of 103: * zero characters, or the current index has passed the end of the 104: * characters in the segment, this method returns {@link #DONE}. 105: * 106: * @return The character at the current index. 107: */ 108: public char current() 109: { 110: if (count == 0 111: || current >= getEndIndex()) 112: return DONE; 113: 114: return array[current]; 115: } 116: 117: /** 118: * Sets the current index to the first character in the segment and returns 119: * that character. If the segment contains zero characters, this method 120: * returns {@link #DONE}. 121: * 122: * @return The first character in the segment, or {@link #DONE} if the 123: * segment contains zero characters. 124: */ 125: public char first() 126: { 127: if (count == 0) 128: return DONE; 129: 130: current = getBeginIndex(); 131: return array[current]; 132: } 133: 134: /** 135: * Returns the index of the first character in the segment. 136: * 137: * @return The index of the first character. 138: */ 139: public int getBeginIndex() 140: { 141: return offset; 142: } 143: 144: /** 145: * Returns the end index for the segment (one position beyond the last 146: * character in the segment - note that this can be outside the range of the 147: * underlying character array). 148: * 149: * @return The end index for the segment. 150: */ 151: public int getEndIndex() 152: { 153: return offset + count; 154: } 155: 156: /** 157: * Returns the index of the current character in the segment. 158: * 159: * @return The index of the current character. 160: */ 161: public int getIndex() 162: { 163: return current; 164: } 165: 166: /** 167: * Sets the current index to point to the last character in the segment and 168: * returns that character. If the segment contains zero characters, the 169: * current index is set to {@link #getEndIndex()} and this method returns 170: * {@link #DONE}. 171: * 172: * @return The last character in the segment, or {@link #DONE} if the 173: * segment contains zero characters. 174: */ 175: public char last() 176: { 177: if (count == 0) 178: { 179: current = getEndIndex(); 180: return DONE; 181: } 182: 183: current = getEndIndex() - 1; 184: return array[current]; 185: } 186: 187: /** 188: * Sets the current index to point to the next character in the segment and 189: * returns that character. If the next character position is past the end of 190: * the segment, the index is set to {@link #getEndIndex()} and the method 191: * returns {@link #DONE}. If the segment contains zero characters, this 192: * method returns {@link #DONE}. 193: * 194: * @return The next character in the segment or {@link #DONE} (if the next 195: * character position is past the end of the segment or if the 196: * segment contains zero characters). 197: */ 198: public char next() 199: { 200: if (count == 0) 201: return DONE; 202: 203: if ((current + 1) >= getEndIndex()) 204: { 205: current = getEndIndex(); 206: return DONE; 207: } 208: 209: current++; 210: return array[current]; 211: } 212: 213: /** 214: * Sets the current index to point to the previous character in the segment 215: * and returns that character. If the current index is equal to 216: * {@link #getBeginIndex()}, or if the segment contains zero characters, this 217: * method returns {@link #DONE}. 218: * 219: * @return The previous character in the segment or {@link #DONE} (if the 220: * current character position is at the beginning of the segment or 221: * if the segment contains zero characters). 222: */ 223: public char previous() 224: { 225: if (count == 0 226: || current == getBeginIndex()) 227: return DONE; 228: 229: current--; 230: return array[current]; 231: } 232: 233: /** 234: * Sets the current index and returns the character at that position (or 235: * {@link #DONE} if the index is equal to {@link #getEndIndex()}. 236: * 237: * @param position the current position. 238: * 239: * @return The character at the specified <code>position</code>, or 240: * {@link #DONE} if <code>position</code> is equal to 241: * {@link #getEndIndex()}. 242: * 243: * @throws IllegalArgumentException if <code>position</code> is not in the 244: * range {@link #getBeginIndex()} to {@link #getEndIndex()}. 245: */ 246: public char setIndex(int position) 247: { 248: if (position < getBeginIndex() 249: || position > getEndIndex()) 250: throw new IllegalArgumentException("position: " + position 251: + ", beginIndex: " + getBeginIndex() 252: + ", endIndex: " + getEndIndex() 253: + ", text: " + toString()); 254: 255: current = position; 256: 257: if (position == getEndIndex()) 258: return DONE; 259: 260: return array[current]; 261: } 262: 263: /** 264: * Returns a <code>String</code> containing the same characters as this 265: * <code>Segment</code>. 266: * 267: * @return A <code>String</code> containing the same characters as this 268: * <code>Segment</code>. 269: */ 270: public String toString() 271: { 272: return (array != null) ? new String(array, offset, count) : ""; 273: } 274: 275: /** 276: * Sets the partial return flag. 277: * 278: * @param p the new value of the flag. 279: * 280: * @since 1.4 281: */ 282: public void setPartialReturn(boolean p) 283: { 284: partialReturn = p; 285: } 286: 287: /** 288: * Returns the partial return flag. 289: * 290: * @return The partial return flag. 291: * @since 1.4 292: */ 293: public boolean isPartialReturn() 294: { 295: return partialReturn; 296: } 297: }