1 /*

     2  * Copyright (c) 2002-2016, the original author or authors.

     3  *

     4  * This software is distributable under the BSD license. See the terms of the

     5  * BSD license in the documentation provided with this software.

     6  *

     7  * http://www.opensource.org/licenses/bsd-license.php

     8  */

     9 package jdk.internal.jline.console;

    10 

    11 import static jdk.internal.jline.internal.Preconditions.checkNotNull;

    12 

    13 /**

    14  * A holder for a {@link StringBuilder} that also contains the current cursor position.

    15  *

    16  * @author <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>

    17  * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>

    18  * @since 2.0

    19  */

    20 public class CursorBuffer

    21 {

    22     private boolean overTyping = false;

    23 

    24     public int cursor = 0;

    25 

    26     public final StringBuilder buffer = new StringBuilder();

    27 

    28     public CursorBuffer copy () {

    29         CursorBuffer that = new CursorBuffer();

    30         that.overTyping = this.overTyping;

    31         that.cursor = this.cursor;

    32         that.buffer.append (this.toString());

    33 

    34         return that;

    35     }

    36 

    37     public boolean isOverTyping() {

    38         return overTyping;

    39     }

    40 

    41     public void setOverTyping(final boolean b) {

    42         overTyping = b;

    43     }

    44 

    45     public int length() {

    46         return buffer.length();

    47     }

    48 

    49     public char nextChar() {

    50         if (cursor == buffer.length()) {

    51             return 0;

    52         } else {

    53             return buffer.charAt(cursor);

    54         }

    55     }

    56 

    57     public char current() {

    58         if (cursor <= 0) {

    59             return 0;

    60         }

    61 

    62         return buffer.charAt(cursor - 1);

    63     }

    64 

    65     /**

    66      * Write the specific character into the buffer, setting the cursor position

    67      * ahead one. The text may overwrite or insert based on the current setting

    68      * of {@link #isOverTyping}.

    69      *

    70      * @param c the character to insert

    71      */

    72     public void write(final char c) {

    73         buffer.insert(cursor++, c);

    74         if (isOverTyping() && cursor < buffer.length()) {

    75             buffer.deleteCharAt(cursor);

    76         }

    77     }

    78 

    79     /**

    80      * Insert the specified chars into the buffer, setting the cursor to the end of the insertion point.

    81      */

    82     public void write(final CharSequence str) {

    83         checkNotNull(str);

    84 

    85         if (buffer.length() == 0) {

    86             buffer.append(str);

    87         }

    88         else {

    89             buffer.insert(cursor, str);

    90         }

    91 

    92         cursor += str.length();

    93 

    94         if (isOverTyping() && cursor < buffer.length()) {

    95             buffer.delete(cursor, cursor + str.length());

    96         }

    97     }

    98 

    99     public boolean clear() {

   100         if (buffer.length() == 0) {

   101             return false;

   102         }

   103 

   104         buffer.delete(0, buffer.length());

   105         cursor = 0;

   106         return true;

   107     }

   108 

   109     public String upToCursor() {

   110         if (cursor <= 0) {

   111             return "";

   112         }

   113 

   114         return buffer.substring(0, cursor);

   115     }

   116 

   117     @Override

   118     public String toString() {

   119         return buffer.toString();

   120     }

   121 }