1 /* 2 * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.lang.model.element; 27 28 import java.util.List; 29 30 /** 31 * Represents a module program element. Provides access to 32 * information about the module, its directives, and its members. 33 * 34 * @see javax.lang.model.util.Elements#getModuleOf 35 * @since 9 36 * @jls 7.7 Module Declarations 37 * @spec JPMS 38 */ 39 public interface ModuleElement extends Element, QualifiedNameable { 40 41 /** 42 * Returns the fully qualified name of this module. For an 43 * {@linkplain #isUnnamed() unnamed module}, an empty name is returned. 44 * 45 * @apiNote If the module name consists of one identifier, then 46 * this method returns that identifier, which is deemed to be 47 * module's fully qualified name despite not being in qualified 48 * form. If the module name consists of more than one identifier, 49 * then this method returns the entire name. 50 * 51 * @return the fully qualified name of this module, or an 52 * empty name if this is an unnamed module 53 * 54 * @jls 6.2 Names and Identifiers 55 */ 56 @Override 57 Name getQualifiedName(); 58 59 /** 60 * Returns the simple name of this module. For an {@linkplain 61 * #isUnnamed() unnamed module}, an empty name is returned. 62 * 63 * @apiNote If the module name consists of one identifier, then 64 * this method returns that identifier. If the module name 65 * consists of more than one identifier, then this method returns 66 * the rightmost such identifier, which is deemed to be the 67 * module's simple name. 68 * 69 * @return the simple name of this module or an empty name if 70 * this is an unnamed module 71 * 72 * @jls 6.2 Names and Identifiers 73 */ 74 @Override 75 Name getSimpleName(); 76 77 /** 78 * Returns the packages within this module. 79 * @return the packages within this module 80 */ 81 @Override 82 List<? extends Element> getEnclosedElements(); 83 84 /** 85 * Returns {@code true} if this is an open module and {@code 86 * false} otherwise. 87 * 88 * @return {@code true} if this is an open module and {@code 89 * false} otherwise 90 */ 91 boolean isOpen(); 92 93 /** 94 * Returns {@code true} if this is an unnamed module and {@code 95 * false} otherwise. 96 * 97 * @return {@code true} if this is an unnamed module and {@code 98 * false} otherwise 99 * 100 * @jls 7.7.5 Unnamed Modules 101 */ 102 boolean isUnnamed(); 103 104 /** 105 * Returns {@code null} since a module is not enclosed by another 106 * element. 107 * 108 * @return {@code null} 109 */ 110 @Override 111 Element getEnclosingElement(); 112 113 /** 114 * Returns the directives contained in the declaration of this module. 115 * @return the directives in the declaration of this module 116 */ 117 List<? extends Directive> getDirectives(); 118 119 /** 120 * The {@code kind} of a directive. 121 * 122 * <p>Note that it is possible additional directive kinds will be added 123 * to accommodate new, currently unknown, language structures added to 124 * future versions of the Java™ programming language. 125 * 126 * @since 9 127 * @spec JPMS 128 */ 129 enum DirectiveKind { 130 /** A "requires (static|transitive)* module-name" directive. */ 131 REQUIRES, 132 /** An "exports package-name [to module-name-list]" directive. */ 133 EXPORTS, 134 /** An "opens package-name [to module-name-list]" directive. */ 135 OPENS, 136 /** A "uses service-name" directive. */ 137 USES, 138 /** A "provides service-name with implementation-name" directive. */ 139 PROVIDES 140 }; 141 142 /** 143 * Represents a directive within the declaration of this 144 * module. The directives of a module declaration configure the 145 * module in the Java Platform Module System. 146 * 147 * @since 9 148 * @spec JPMS 149 */ 150 interface Directive { 151 /** 152 * Returns the {@code kind} of this directive. 153 * 154 * @return the kind of this directive 155 */ 156 DirectiveKind getKind(); 157 158 /** 159 * Applies a visitor to this directive. 160 * 161 * @param <R> the return type of the visitor's methods 162 * @param <P> the type of the additional parameter to the visitor's methods 163 * @param v the visitor operating on this directive 164 * @param p additional parameter to the visitor 165 * @return a visitor-specified result 166 */ 167 <R, P> R accept(DirectiveVisitor<R, P> v, P p); 168 } 169 170 /** 171 * A visitor of module directives, in the style of the visitor design 172 * pattern. Classes implementing this interface are used to operate 173 * on a directive when the kind of directive is unknown at compile time. 174 * When a visitor is passed to a directive's {@link Directive#accept 175 * accept} method, the <code>visit<i>Xyz</i></code> method applicable 176 * to that directive is invoked. 177 * 178 * <p> Classes implementing this interface may or may not throw a 179 * {@code NullPointerException} if the additional parameter {@code p} 180 * is {@code null}; see documentation of the implementing class for 181 * details. 182 * 183 * <p> <b>WARNING:</b> It is possible that methods will be added to 184 * this interface to accommodate new, currently unknown, language 185 * structures added to future versions of the Java™ programming 186 * language. Methods to accommodate new language constructs will 187 * be added in a source <em>compatible</em> way using 188 * <em>default methods</em>. 189 * 190 * @param <R> the return type of this visitor's methods. Use {@link 191 * Void} for visitors that do not need to return results. 192 * @param <P> the type of the additional parameter to this visitor's 193 * methods. Use {@code Void} for visitors that do not need an 194 * additional parameter. 195 * 196 * @since 9 197 * @spec JPMS 198 */ 199 interface DirectiveVisitor<R, P> { 200 /** 201 * Visits any directive as if by passing itself to that 202 * directive's {@link Directive#accept accept} method and passing 203 * {@code null} for the additional parameter. 204 * The invocation {@code v.visit(d)} is equivalent to 205 * {@code d.accept(v, null)}. 206 * @param d the directive to visit 207 * @return a visitor-specified result 208 * @implSpec This implementation is {@code visit(d, null)} 209 */ 210 default R visit(Directive d) { 211 return d.accept(this, null); 212 } 213 214 /** 215 * Visits any directive as if by passing itself to that 216 * directive's {@link Directive#accept accept} method. 217 * The invocation {@code v.visit(d, p)} is equivalent to 218 * {@code d.accept(v, p)}. 219 * @param d the directive to visit 220 * @param p a visitor-specified parameter 221 * @return a visitor-specified result 222 */ 223 default R visit(Directive d, P p) { 224 return d.accept(this, p); 225 } 226 227 /** 228 * Visits a {@code requires} directive. 229 * @param d the directive to visit 230 * @param p a visitor-specified parameter 231 * @return a visitor-specified result 232 */ 233 R visitRequires(RequiresDirective d, P p); 234 235 /** 236 * Visits an {@code exports} directive. 237 * @param d the directive to visit 238 * @param p a visitor-specified parameter 239 * @return a visitor-specified result 240 */ 241 R visitExports(ExportsDirective d, P p); 242 243 /** 244 * Visits an {@code opens} directive. 245 * @param d the directive to visit 246 * @param p a visitor-specified parameter 247 * @return a visitor-specified result 248 */ 249 R visitOpens(OpensDirective d, P p); 250 251 /** 252 * Visits a {@code uses} directive. 253 * @param d the directive to visit 254 * @param p a visitor-specified parameter 255 * @return a visitor-specified result 256 */ 257 R visitUses(UsesDirective d, P p); 258 259 /** 260 * Visits a {@code provides} directive. 261 * @param d the directive to visit 262 * @param p a visitor-specified parameter 263 * @return a visitor-specified result 264 */ 265 R visitProvides(ProvidesDirective d, P p); 266 267 /** 268 * Visits an unknown directive. 269 * This can occur if the language evolves and new kinds of directive are added. 270 * @param d the directive to visit 271 * @param p a visitor-specified parameter 272 * @return a visitor-specified result 273 * @throws UnknownDirectiveException a visitor implementation may optionally throw this exception 274 * @implSpec This implementation throws {@code new UnknownDirectiveException(d, p)}. 275 */ 276 default R visitUnknown(Directive d, P p) { 277 throw new UnknownDirectiveException(d, p); 278 } 279 } 280 281 /** 282 * A dependency of a module. 283 * @since 9 284 * @spec JPMS 285 */ 286 interface RequiresDirective extends Directive { 287 /** 288 * Returns whether or not this is a static dependency. 289 * @return whether or not this is a static dependency 290 */ 291 boolean isStatic(); 292 293 /** 294 * Returns whether or not this is a transitive dependency. 295 * @return whether or not this is a transitive dependency 296 */ 297 boolean isTransitive(); 298 299 /** 300 * Returns the module that is required 301 * @return the module that is required 302 */ 303 ModuleElement getDependency(); 304 } 305 306 /** 307 * An exported package of a module. 308 * @since 9 309 * @spec JPMS 310 */ 311 interface ExportsDirective extends Directive { 312 313 /** 314 * Returns the package being exported. 315 * @return the package being exported 316 */ 317 PackageElement getPackage(); 318 319 /** 320 * Returns the specific modules to which the package is being exported, 321 * or null, if the package is exported to all modules which 322 * have readability to this module. 323 * @return the specific modules to which the package is being exported 324 */ 325 List<? extends ModuleElement> getTargetModules(); 326 } 327 328 /** 329 * An opened package of a module. 330 * @since 9 331 * @spec JPMS 332 */ 333 interface OpensDirective extends Directive { 334 335 /** 336 * Returns the package being opened. 337 * @return the package being opened 338 */ 339 PackageElement getPackage(); 340 341 /** 342 * Returns the specific modules to which the package is being open 343 * or null, if the package is open all modules which 344 * have readability to this module. 345 * @return the specific modules to which the package is being opened 346 */ 347 List<? extends ModuleElement> getTargetModules(); 348 } 349 350 /** 351 * An implementation of a service provided by a module. 352 * @since 9 353 * @spec JPMS 354 */ 355 interface ProvidesDirective extends Directive { 356 /** 357 * Returns the service being provided. 358 * @return the service being provided 359 */ 360 TypeElement getService(); 361 362 /** 363 * Returns the implementations of the service being provided. 364 * @return the implementations of the service being provided 365 */ 366 List<? extends TypeElement> getImplementations(); 367 } 368 369 /** 370 * A reference to a service used by a module. 371 * @since 9 372 * @spec JPMS 373 */ 374 interface UsesDirective extends Directive { 375 /** 376 * Returns the service that is used. 377 * @return the service that is used 378 */ 379 TypeElement getService(); 380 } 381 }