Source for java.awt.im.InputMethodRequests

   1: /* InputMethodRequests.java -- handles text insertion via input methods
   2:    Copyright (C) 2002, 2005  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 java.awt.im;
  39: 
  40: import java.awt.Component;
  41: import java.awt.Rectangle;
  42: import java.awt.font.TextHitInfo;
  43: import java.awt.event.InputMethodListener;
  44: import java.text.AttributedCharacterIterator;
  45: import java.text.AttributedCharacterIterator.Attribute;
  46: 
  47: /**
  48:  * This interface handles requests made by input methods on text editing
  49:  * components. A component must specify a handler for input methods that
  50:  * implements this interface, and which supports one of two user interfaces:
  51:  * <ul><li><em>on-the-spot</em>: composed text is shown in place</li>
  52:  * <li><em>below-the-spot</em>: composed text is in a separate window,
  53:  * usually below the main text window, until it is committed into place at
  54:  * the insertion point, overwriting any selected text</li></ul>
  55:  *
  56:  * @author Eric Blake (ebb9@email.byu.edu)
  57:  * @see Component#getInputMethodRequests()
  58:  * @see InputMethodListener
  59:  * @since 1.2
  60:  * @status updated to 1.4
  61:  */
  62: public interface InputMethodRequests
  63: {
  64:   /**
  65:    * Gets the location of a given offset of the text. This can be used to
  66:    * position a composition window near the location of where the composed
  67:    * text will be inserted.
  68:    *
  69:    * <p>If the component has composed text (from the most recent
  70:    * InputMethodEvent), then offset 0 indicates the location of the first
  71:    * character of this composed text. Otherwise, the offset is ignored, and
  72:    * the location should be the beginning of the final line of selected
  73:    * text (in horizontal left-to-right text, like English, this would be the
  74:    * lower left corner of the selction; in vertical top-to-bottom text, like
  75:    * Chinese, this would be the top right corner of the selection).
  76:    *
  77:    * <p>The location returned is a 0-thickness caret (either horizontal or
  78:    * vertical, depending on text flow), mapped to absolute screen coordinates.
  79:    *
  80:    * @param offset offset within composed text, or null
  81:    * @return the screen location of the caret at the offset
  82:    */
  83:   Rectangle getTextLocation(TextHitInfo offset);
  84: 
  85:   /**
  86:    * Get the text offset for the given screen coordinate. The offset is
  87:    * relative to the composed text, and the return is null if it is outside
  88:    * the range of composed text. For example, this can be used to find
  89:    * where a mouse click should pop up a text composition window.
  90:    *
  91:    * @param x the x screen coordinate
  92:    * @param y the y screen coordinate
  93:    * @return a text hit info describing the composed text offset
  94:    */
  95:   TextHitInfo getLocationOffset(int x, int y);
  96: 
  97:   /**
  98:    * Gets the offset where the committed text exists in the text editing
  99:    * component. This can be used to examine the text surrounding the insert
 100:    * position.
 101:    *
 102:    * @return the offset of the insert position
 103:    */
 104:   int getInsertPositionOffset();
 105: 
 106:   /**
 107:    * Gets an interator which provides access to the text and its attributes,
 108:    * except for the uncommitted text. The input method may provide a list of
 109:    * attributes it is interested in; and the iterator need not provide
 110:    * information on the remaining attributes. If the attribute list is null,
 111:    * the iterator must list all attributes.
 112:    *
 113:    * @param beginIndex the index of the first character in the iteration
 114:    * @param endIndex the index of the last character in the iteration
 115:    * @param attributes a list of attributes interested in, or null
 116:    * @return an iterator over the region of text with its attributes
 117:    */
 118:   AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex,
 119:                                                Attribute[] attributes);
 120: 
 121:   /**
 122:    * Gets the length of committed text.
 123:    *
 124:    * @return the number of committed characters
 125:    */
 126:   int getCommittedTextLength();
 127: 
 128:   /**
 129:    * Gets the latest committed text, and removes it from the component's text
 130:    * body. This allows an input method to provide an "Undo" command. In
 131:    * general, this should only be supported immediately after a commit, and
 132:    * not when other actions intervene; if not supported, simply return null.
 133:    * The input method may provide a list of attributes it is interested in;
 134:    * and the iterator need not provide information on the remaining attributes.
 135:    * If the attribute list is null, the iterator must list all attributes.
 136:    *
 137:    * @param attributes a list of attributes interested in, or null
 138:    * @return the latest committed text, or null
 139:    */
 140:   AttributedCharacterIterator cancelLatestCommittedText
 141:     (Attribute[] attributes);
 142: 
 143:   /**
 144:    * Gets the currently selected text. One use of this is to implement a
 145:    * "Reconvert" feature in an input method, which modifies the selection
 146:    * based on the text in the composition window. The input method may
 147:    * provide a list of attributes it is interested in; and the iterator need
 148:    * not provide information on the remaining attributes. If the attribute
 149:    * list is null, the iterator must list all attributes.
 150:    *
 151:    * @param attributes a list of attributes interested in, or null
 152:    * @return the current selection
 153:    */
 154:   AttributedCharacterIterator getSelectedText(Attribute[] attributes);
 155: } // interface InputMethodRequests