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| 31 | Defines a contract between user-interface components and an assistive technology |
| 32 | that provides access to those components. If a Java application fully supports |
| 33 | the Java Accessibility API, then it should be compatible with, and friendly |
| 34 | toward, assistive technologies such as screen readers, screen magnifiers, |
| 35 | etc. With a Java application that fully supports the Java Accessibility |
| 36 | API, no screen reader off screen model would be necessary because the API |
| 37 | provides all of the information normally contained in an off screen model. |
| 38 | |
| 39 | <P>The Java Accessibility API package consists of 8 Java programming language |
| 40 | interfaces, and 6 Java programming language classes. These are described |
| 41 | below. |
| 42 | <H3> |
| 43 | <A NAME="Accessible"></A><A HREF="Accessible.html">Interface Accessible</A></H3> |
| 44 | <A HREF="Accessible.html">Interface Accessible</A> is the main interface |
| 45 | of the Java Accessibility API. All components that support the Java Accessibility |
| 46 | API must implement this interface. It contains a single method, <TT>getAccessibleContext</TT>, |
| 47 | that returns an instance of the class <A HREF="#AccessibleContext">AccessibleContext</A>. |
| 48 | Sun thinks that implementing this interface is the absolute minimum requirement |
| 49 | of every object that is part of the user interface of a Java application, |
| 50 | if that program is to be compatible with assistive technologies. |
| 51 | <H3> |
| 52 | <A NAME="AccessibleContext"></A><A HREF="AccessibleContext.html">Class |
| 53 | AccessibleContext</A></H3> |
| 54 | <A HREF="AccessibleContext.html">AccessibleContext</A> represents the minimum |
| 55 | information all accessible objects return and is obtained by calling the |
| 56 | <TT>getAccessibleContext</TT> method on an object that implements the <A HREF="#Accessible">Accessible</A> |
| 57 | interface. This information includes the accessible name, description, |
| 58 | <A HREF="#AccessibleRole">role</A>, and <A HREF="#AccessibleState">state</A> |
| 59 | of the object, as well as information about the parent and children of |
| 60 | the object. In addition, JavaBeans <SUP><FONT SIZE=-2>TM</FONT></SUP> |
| 61 | property change support is also included to allow assisitive technologies |
| 62 | learn when the values of the accessible properties change. AccessibleContext |
| 63 | also contains methods for obtaining more specific accessibility information |
| 64 | about a component. If the component supports it, these methods will return |
| 65 | an object that implements one or more of the following interfaces: |
| 66 | <UL> |
| 67 | <LI> |
| 68 | <B><A HREF="#AccessibleAction">AccessibleAction</A></B> - the object can |
| 69 | perform one or more actions. This interface provides the standard mechanism |
| 70 | for an assistive technology to determine what those actions are and tell |
| 71 | the object to perform those actions. Any object that can be manipulated |
| 72 | should return an object that implements this interface when the <TT>getAccessibleAction</TT> |
| 73 | method is called on an AccessibleContext.</LI> |
| 74 | |
| 75 | <LI> |
| 76 | <B><A HREF="#AccessibleComponent">AccessibleComponent</A></B> - the object |
| 77 | has a graphical representation. This interface provides the standard mechanism |
| 78 | for an assistive technology to determine and set the graphical representation |
| 79 | of the object. Any object that is rendered on the screen should return |
| 80 | an object that implements this interface when the <TT>getAccessibleComponent</TT> |
| 81 | method is called on an AccessibleContext.</LI> |
| 82 | |
| 83 | <LI> |
| 84 | <B><A HREF="#AccessibleSelection">AccessibleSelection</A></B> - the object |
| 85 | allows its children to be selected. This interface provides the standard |
| 86 | mechanism for an assistive technology to determine the currently selected |
| 87 | children as well as modify the selection set. Any object that has children |
| 88 | that can be selected should return an object that implements this interface |
| 89 | when the <TT>getAccessibleSelection</TT> method is called on an AccessibleContext.</LI> |
| 90 | |
| 91 | <LI> |
| 92 | <B><A HREF="#AccessibleText">AccessibleText</A></B> - the object presents |
| 93 | editable textual information on the display. This interface provides the |
| 94 | standard mechanism for an assistive technology to access that text via |
| 95 | its content, attributes, and spatial location. Any object that contains |
| 96 | editable text should return an object that implements this interface when |
| 97 | the <TT>getAccessibleText</TT> method is called on an AccessibleContext.</LI> |
| 98 | |
| 99 | <LI> |
| 100 | <B><A HREF="#AccessibleHypertext">AccessibleHypertext</A></B> - the object |
| 101 | presents hypertext information on the display. This interface provides |
| 102 | the standard mechanism for an assistive technology to access that hypertext |
| 103 | via its content, attributes, and spatial location. Any object that contains |
| 104 | hypertext should return an object that implements this interface when the |
| 105 | <TT>getAccessibleText</TT> method is called on an AccessibleContext.</LI> |
| 106 | |
| 107 | <LI> |
| 108 | <B><A HREF="#AccessibleValue">AccessibleValue</A></B> - the object supports |
| 109 | a numerical value. This interface provides the standard mechanism for an |
| 110 | assistive technology to determine and set the current value of the object, |
| 111 | as well as the minimum and maximum values. Any object that supports a numerical |
| 112 | value should return an object that implements this interface when the <TT>getAccessibleValue</TT> |
| 113 | method is called on an AccessibleContext.</LI> |
| 114 | </UL> |
| 115 | |
| 116 | <H3> |
| 117 | <A NAME="AccessibleRole"></A><A HREF="AccessibleRole.html">Class AccessibleRole</A></H3> |
| 118 | This class encapsulates the Accessible object's role in the user interface |
| 119 | and is obtained by calling the <TT>getAccessibleRole</TT> method on an |
| 120 | <A HREF="#AccessibleContext">AccessibleContext</A>. Accessible roles include |
| 121 | "Check box", "Menu Item", "Panel", etc. These roles are identified by the |
| 122 | constants in this class such as <TT>AccessibleRole.CHECK_BOX, AccessibleRole.MENU_ITEM,</TT> |
| 123 | and <TT>AccessibleRole.PANEL</TT>. The constants in this class present |
| 124 | a strongly typed enumeration of common object roles. A public constructor |
| 125 | for this class has been purposely omitted and applications should use one |
| 126 | of the constants from this class. Although this class pre-defines a large |
| 127 | list of standard roles, it is extensible so additional programmer-defined |
| 128 | roles can be added in the future without needing to modify the base class. |
| 129 | |
| 130 | <H3> |
| 131 | <A NAME="AccessibleState"></A><A HREF="AccessibleState.html">Class AccessibleState</A></H3> |
| 132 | This class encapsulates a particular state of the Accessible object. Accessible |
| 133 | states include things like "Armed", "Busy", "Checked", "Focused", etc. |
| 134 | These roles are identified by the constants in this class such as <TT>AccessibleState.ARMED, |
| 135 | AccessibleState.BUSY, AccessibleState.CHECKED,</TT> and <TT>AccessibleState.FOCUSED</TT>. |
| 136 | The sum of all the states of an Accessible object is called the <A HREF="#AccessibleStateSet">AccessibleStateSet</A>, |
| 137 | and can be obtained by calling the <TT>getAccessibleStateSet</TT> method |
| 138 | on an <A HREF="#AccessibleContext">AccessibleContext</A>. |
| 139 | |
| 140 | <P>The constants in this class present a strongly typed enumeration of |
| 141 | common object roles. A public constructor for this class has been purposely |
| 142 | omitted and applications should use one of the constants from this class. |
| 143 | Although this class pre-defines a large list of standard roles, it is extensible |
| 144 | so additional, programmer-defined roles can be added in the future without |
| 145 | needing to modify the base class. |
| 146 | |
| 147 | <H3> |
| 148 | <A NAME="AccessibleStateSet"></A><A HREF="AccessibleStateSet.html">Class |
| 149 | AccessibleStateSet</A></H3> |
| 150 | This class encapsulates a collection of states of the Accessible object |
| 151 | and is obtained by calling the <TT>getAccessibleStateSet</TT> method on |
| 152 | an <A HREF="#AccessibleContext">AccessibleContext</A>. Since an object |
| 153 | might have multiple states (e.g. it might be both "Checked" and "Focused"), |
| 154 | this class is needed to encapsulate a collection of these states. Methods |
| 155 | in the class provide for retrieving the individual <A HREF="#AccessibleState">AccessibleStates</A> |
| 156 | on the state set. |
| 157 | <H3> |
| 158 | <A NAME="AccessibleBundle"></A><A HREF="AccessibleBundle.html">Class AccessibleBundle</A></H3> |
| 159 | This class is used to maintain a strongly typed enumeration. It is the |
| 160 | super class of both the <A HREF="#AccessibleRole">AccessibleRole</A> and |
| 161 | <A HREF="#AccessibleState">AccessibleState</A> classes. Programmers normally |
| 162 | do not interact with this class directly, but will instead use the <A HREF="#AccessibleRole">AccessibleRole</A> |
| 163 | and <A HREF="#AccessibleState">AccessibleState</A> classes. |
| 164 | |
| 165 | <H3> |
| 166 | <A NAME="AccessibleAction"></A><A HREF="AccessibleAction.html">Interface |
| 167 | AccessibleAction</A></H3> |
| 168 | The <A HREF="AccessibleAction.html">AccessibleAction</A> interface should |
| 169 | be supported by any object that can perform one or more actions. This interface |
| 170 | provides the standard mechanism for an assistive technology to determine |
| 171 | what those actions are as well as tell the object to perform those actions. |
| 172 | Any object that can be manipulated should support this interface. |
| 173 | |
| 174 | <P>Applications can determine if an object supports the AccessibleAction |
| 175 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 176 | (see <A HREF="#Accessible">Accessible</A>) and then calling the <TT>getAccessibleAction</TT> |
| 177 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 178 | value is not null, the object supports this interface. |
| 179 | <H3> |
| 180 | <A NAME="AccessibleComponent"></A><A HREF="AccessibleComponent.html">Interface |
| 181 | AccessibleComponent</A></H3> |
| 182 | The <A HREF="AccessibleComponent.html">AccessibleComponent</A> interface |
| 183 | should be supported by any object that is rendered on the screen. This |
| 184 | interface provides the standard mechanism for an assistive technology to |
| 185 | determine and set the graphical representation of an object. |
| 186 | |
| 187 | <P>Applications can determine if an object supports the AccessibleComponent |
| 188 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 189 | (see <A HREF="#Accessible">Accessible</A>) and then calling the <TT>getAccessibleComponent</TT> |
| 190 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 191 | value is not null, the object supports this interface. |
| 192 | <H3> |
| 193 | <A NAME="AccessibleSelection"></A><A HREF="AccessibleSelection.html">Interface |
| 194 | AccessibleSelection</A></H3> |
| 195 | The <A HREF="AccessibleSelection.html">AccessibleSelection</A> interface |
| 196 | provides the standard mechanism for an assistive technology to determine |
| 197 | what the current selected children are, as well as modify the selection |
| 198 | set. Any object that has children that can be selected should support this |
| 199 | the AccessibleSelection interface. |
| 200 | |
| 201 | <P>Applications can determine if an object supports the AccessibleSelection |
| 202 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 203 | (see <A HREF="#Accessible">Accessible</A>) and then calling the <TT>getAccessibleSelection</TT> |
| 204 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 205 | value is not null, the object supports this interface. |
| 206 | <H3> |
| 207 | <A NAME="AccessibleText"></A><A HREF="AccessibleText.html">Interface AccessibleText</A></H3> |
| 208 | Interface <A HREF="AccessibleText.html">AccessibleText</A> is the contract |
| 209 | for making rich, editable text Accessible. Not all text displayed on the |
| 210 | screen is rich and editable (e.g. text contained in buttons, labels, menus, |
| 211 | etc., which users aren't expected to manipulate). However, objects containing |
| 212 | editable text must implement interface AccessibleText if they are to interoperate |
| 213 | with assistive technologies. |
| 214 | |
| 215 | <P>This interface provides support for going between pixel coordinates |
| 216 | and the text at a given pixel coordinate, for retrieving the letter, word, |
| 217 | and sentence at, before, or after a given position in the text. This interface |
| 218 | provides support for retrieving the attributes of the character at a given |
| 219 | position in the text (font, font size, style, etc.), as well as getting |
| 220 | the selected text (if any), the length of the text, and the location of |
| 221 | the text caret. |
| 222 | |
| 223 | <P>Applications can determine if an object supports the AccessibleText |
| 224 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 225 | (see <A HREF="#Accessible">Accessible</A>) and then calling the <TT>getAccessibleText</TT> |
| 226 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 227 | value is not null, the object supports this interface. |
| 228 | <H3><A NAME="AccessibleHypertext"></A> |
| 229 | <A HREF="AccessibleHypertext.html">Interface AccessibleHypertext</A></H3> |
| 230 | The <A HREF="AccessibleHypertext.html">AccessibleHypertext</A> interface |
| 231 | should be supported by any object that presents hypertext information on |
| 232 | the display. This interface provides the standard mechanism for an assistive |
| 233 | technology to access that text via its content, attributes, and spatial |
| 234 | location. It also provides standard mechanisms for manipulating <A HREF="#AccessibleHyperlink">hyperlinks</A>. |
| 235 | Applications can determine if an object supports the AccessibleHypertext |
| 236 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 237 | (see <A HREF="#Accessible">Accessible</A>) and then calling the AccessibleContext.getAccessibleText() |
| 238 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 239 | value is a class which extends AccessibleHypertext, then that object supports |
| 240 | AccessibleHypertext. |
| 241 | <H3> |
| 242 | <A NAME="AccessibleHyperlink"></A><A HREF="AccessibleHyperlink.html">Interface |
| 243 | AccessibleHyperlink</A></H3> |
| 244 | An object that is a hyperlink should support the <A HREF="AccessibleHyperlink.html">AccessibleHyperlink</A> |
| 245 | interface. An object that implements this interface will be returned |
| 246 | by calling the getLink method on an <A HREF="#AccessibleHypertext">AccessibleHypertext</A> |
| 247 | object. |
| 248 | <H3> |
| 249 | <A NAME="AccessibleValue"></A><A HREF="AccessibleValue.html">Interface |
| 250 | AccessibleValue</A></H3> |
| 251 | The <A HREF="AccessibleValue.html">AccessibleValue</A> interface should |
| 252 | be supported by any object that supports a numerical value (e.g., a scroll |
| 253 | bar). This interface provides the standard mechanism for an assistive technology |
| 254 | to determine and set the numerical value as well as get the minimum and |
| 255 | maximum values. |
| 256 | |
| 257 | <P>Applications can determine if an object supports the AccessibleValue |
| 258 | interface by first obtaining its <A HREF="#AccessibleContext">AccessibleContext</A> |
| 259 | (see <A HREF="#Accessible">Accessible</A>) and then calling the <TT>getAccessibleValue</TT> |
| 260 | method of <A HREF="#AccessibleContext">AccessibleContext</A>. If the return |
| 261 | value is not null, the object supports this interface. |
| 262 | |
| 263 | @since 1.2 |
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