src/jexer/teditor/Line.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2019 Kevin Lamonte
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24  * DEALINGS IN THE SOFTWARE.
  25  *
  26  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  27  * @version 1
  28  */
  29 package jexer.teditor;
  30
  31 import java.util.ArrayList;
  32 import java.util.List;
  33
  34 import jexer.bits.CellAttributes;
  35
  36 /**
  37  * A Line represents a single line of text on the screen, as a collection of
  38  * words.
  39  */
  40 public class Line {
  41
  42     // ------------------------------------------------------------------------
  43     // Variables --------------------------------------------------------------
  44     // ------------------------------------------------------------------------
  45
  46     /**
  47      * The list of words.
  48      */
  49     private ArrayList<Word> words = new ArrayList<Word>();
  50
  51     /**
  52      * The default color for the TEditor class.
  53      */
  54     private CellAttributes defaultColor = null;
  55
  56     /**
  57      * The text highlighter to use.
  58      */
  59     private Highlighter highlighter = null;
  60
  61     /**
  62      * The current cursor position on this line.
  63      */
  64     private int cursor = 0;
  65
  66     /**
  67      * The raw text of this line, what is passed to Word to determine
  68      * highlighting behavior.
  69      */
  70     private StringBuilder rawText;
  71
  72     // ------------------------------------------------------------------------
  73     // Constructors -----------------------------------------------------------
  74     // ------------------------------------------------------------------------
  75
  76     /**
  77      * Construct a new Line from an existing text string, and highlight
  78      * certain strings.
  79      *
  80      * @param str the text string
  81      * @param defaultColor the color for unhighlighted text
  82      * @param highlighter the highlighter to use
  83      */
  84     public Line(final String str, final CellAttributes defaultColor,
  85         final Highlighter highlighter) {
  86
  87         this.defaultColor = defaultColor;
  88         this.highlighter = highlighter;
  89         this.rawText = new StringBuilder(str);
  90
  91         scanLine();
  92     }
  93
  94     /**
  95      * Construct a new Line from an existing text string.
  96      *
  97      * @param str the text string
  98      * @param defaultColor the color for unhighlighted text
  99      */
 100     public Line(final String str, final CellAttributes defaultColor) {
 101         this(str, defaultColor, null);
 102     }
 103
 104     // ------------------------------------------------------------------------
 105     // Line -------------------------------------------------------------------
 106     // ------------------------------------------------------------------------
 107
 108     /**
 109      * Get a (shallow) copy of the words in this line.
 110      *
 111      * @return a copy of the word list
 112      */
 113     public List<Word> getWords() {
 114         return new ArrayList<Word>(words);
 115     }
 116
 117     /**
 118      * Get the current cursor position.
 119      *
 120      * @return the cursor position
 121      */
 122     public int getCursor() {
 123         return cursor;
 124     }
 125
 126     /**
 127      * Set the current cursor position.
 128      *
 129      * @param cursor the new cursor position
 130      */
 131     public void setCursor(final int cursor) {
 132         if ((cursor < 0)
 133             || ((cursor >= getDisplayLength())
 134                 && (getDisplayLength() > 0))
 135         ) {
 136             throw new IndexOutOfBoundsException("Max length is " +
 137                 getDisplayLength() + ", requested position " + cursor);
 138         }
 139         this.cursor = cursor;
 140     }
 141
 142     /**
 143      * Get the on-screen display length.
 144      *
 145      * @return the number of cells needed to display this line
 146      */
 147     public int getDisplayLength() {
 148         int n = rawText.length();
 149
 150         // For now just return the raw text length.
 151         if (n > 0) {
 152             // If we have any visible characters, add one to the display so
 153             // that the cursor is immediately after the data.
 154             return n + 1;
 155         }
 156         return n;
 157     }
 158
 159     /**
 160      * Get the raw string that matches this line.
 161      *
 162      * @return the string
 163      */
 164     public String getRawString() {
 165         return rawText.toString();
 166     }
 167
 168     /**
 169      * Scan rawText and make words out of it.
 170      */
 171     private void scanLine() {
 172         words.clear();
 173         Word word = new Word(this.defaultColor, this.highlighter);
 174         words.add(word);
 175         for (int i = 0; i < rawText.length(); i++) {
 176             char ch = rawText.charAt(i);
 177             Word newWord = word.addChar(ch);
 178             if (newWord != word) {
 179                 words.add(newWord);
 180                 word = newWord;
 181             }
 182         }
 183         for (Word w: words) {
 184             w.applyHighlight();
 185         }
 186     }
 187
 188     /**
 189      * Decrement the cursor by one.  If at the first column, do nothing.
 190      *
 191      * @return true if the cursor position changed
 192      */
 193     public boolean left() {
 194         if (cursor == 0) {
 195             return false;
 196         }
 197         cursor--;
 198         return true;
 199     }
 200
 201     /**
 202      * Increment the cursor by one.  If at the last column, do nothing.
 203      *
 204      * @return true if the cursor position changed
 205      */
 206     public boolean right() {
 207         if (getDisplayLength() == 0) {
 208             return false;
 209         }
 210         if (cursor == getDisplayLength() - 1) {
 211             return false;
 212         }
 213         cursor++;
 214         return true;
 215     }
 216
 217     /**
 218      * Go to the first column of this line.
 219      *
 220      * @return true if the cursor position changed
 221      */
 222     public boolean home() {
 223         if (cursor > 0) {
 224             cursor = 0;
 225             return true;
 226         }
 227         return false;
 228     }
 229
 230     /**
 231      * Go to the last column of this line.
 232      *
 233      * @return true if the cursor position changed
 234      */
 235     public boolean end() {
 236         if (cursor != getDisplayLength() - 1) {
 237             cursor = getDisplayLength() - 1;
 238             if (cursor < 0) {
 239                 cursor = 0;
 240             }
 241             return true;
 242         }
 243         return false;
 244     }
 245
 246     /**
 247      * Delete the character under the cursor.
 248      */
 249     public void del() {
 250         assert (words.size() > 0);
 251
 252         if (cursor < getDisplayLength()) {
 253             rawText.deleteCharAt(cursor);
 254         }
 255
 256         // Re-scan the line to determine the new word boundaries.
 257         scanLine();
 258     }
 259
 260     /**
 261      * Delete the character immediately preceeding the cursor.
 262      */
 263     public void backspace() {
 264         if (left()) {
 265             del();
 266         }
 267     }
 268
 269     /**
 270      * Insert a character at the cursor.
 271      *
 272      * @param ch the character to insert
 273      */
 274     public void addChar(final char ch) {
 275         if (cursor < getDisplayLength() - 1) {
 276             rawText.insert(cursor, ch);
 277         } else {
 278             rawText.append(ch);
 279         }
 280         scanLine();
 281         cursor++;
 282     }
 283
 284     /**
 285      * Replace a character at the cursor.
 286      *
 287      * @param ch the character to replace
 288      */
 289     public void replaceChar(final char ch) {
 290         if (cursor < getDisplayLength() - 1) {
 291             rawText.setCharAt(cursor, ch);
 292         } else {
 293             rawText.append(ch);
 294         }
 295         scanLine();
 296         cursor++;
 297     }
 298
 299 }