001/* InputMethodRequests.java -- handles text insertion via input methods 002 Copyright (C) 2002, 2005 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package java.awt.im; 039 040import java.awt.Component; 041import java.awt.Rectangle; 042import java.awt.font.TextHitInfo; 043import java.awt.event.InputMethodListener; 044import java.text.AttributedCharacterIterator; 045import java.text.AttributedCharacterIterator.Attribute; 046 047/** 048 * This interface handles requests made by input methods on text editing 049 * components. A component must specify a handler for input methods that 050 * implements this interface, and which supports one of two user interfaces: 051 * <ul><li><em>on-the-spot</em>: composed text is shown in place</li> 052 * <li><em>below-the-spot</em>: composed text is in a separate window, 053 * usually below the main text window, until it is committed into place at 054 * the insertion point, overwriting any selected text</li></ul> 055 * 056 * @author Eric Blake (ebb9@email.byu.edu) 057 * @see Component#getInputMethodRequests() 058 * @see InputMethodListener 059 * @since 1.2 060 * @status updated to 1.4 061 */ 062public interface InputMethodRequests 063{ 064 /** 065 * Gets the location of a given offset of the text. This can be used to 066 * position a composition window near the location of where the composed 067 * text will be inserted. 068 * 069 * <p>If the component has composed text (from the most recent 070 * InputMethodEvent), then offset 0 indicates the location of the first 071 * character of this composed text. Otherwise, the offset is ignored, and 072 * the location should be the beginning of the final line of selected 073 * text (in horizontal left-to-right text, like English, this would be the 074 * lower left corner of the selction; in vertical top-to-bottom text, like 075 * Chinese, this would be the top right corner of the selection). 076 * 077 * <p>The location returned is a 0-thickness caret (either horizontal or 078 * vertical, depending on text flow), mapped to absolute screen coordinates. 079 * 080 * @param offset offset within composed text, or null 081 * @return the screen location of the caret at the offset 082 */ 083 Rectangle getTextLocation(TextHitInfo offset); 084 085 /** 086 * Get the text offset for the given screen coordinate. The offset is 087 * relative to the composed text, and the return is null if it is outside 088 * the range of composed text. For example, this can be used to find 089 * where a mouse click should pop up a text composition window. 090 * 091 * @param x the x screen coordinate 092 * @param y the y screen coordinate 093 * @return a text hit info describing the composed text offset 094 */ 095 TextHitInfo getLocationOffset(int x, int y); 096 097 /** 098 * Gets the offset where the committed text exists in the text editing 099 * 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