001package io.ebean.enhance.entity; 002 003import io.ebean.enhance.asm.ClassVisitor; 004import io.ebean.enhance.asm.FieldVisitor; 005import io.ebean.enhance.asm.Label; 006import io.ebean.enhance.asm.MethodVisitor; 007import io.ebean.enhance.asm.Opcodes; 008import io.ebean.enhance.common.ClassMeta; 009import io.ebean.enhance.common.EnhanceConstants; 010import io.ebean.enhance.common.VisitUtil; 011 012/** 013 * Generate the equals hashCode method using the identity. 014 * <p> 015 * This will add a _ebean_getIdentity() equals() and hashCode() methods based on 016 * having a single ID property and no existing equals() or hashCode() methods. 017 * </p> 018 */ 019public class MethodEquals implements Opcodes, EnhanceConstants { 020 021 private static final String _EBEAN_GET_IDENTITY = "_ebean_getIdentity"; 022 023 /** 024 * Adds equals(), hashCode() and _ebean_getIdentity() methods. 025 * <p> 026 * If the class already has a equals() or hashCode() method defined then 027 * these methods are not added (its a noop). 028 * </p> 029 * 030 * @param idFieldIndex 031 * the index of the id field 032 */ 033 public static void addMethods(ClassVisitor cv, ClassMeta meta, int idFieldIndex, FieldMeta idFieldMeta) { 034 035 if (meta.hasEqualsOrHashCode()) { 036 // already has a equals or hashcode method... 037 // so we will not add our identity based one 038 if (meta.isLog(2)) { 039 meta.log("already has a equals() or hashCode() method. Not adding the identity based one."); 040 } 041 } else { 042 if (meta.isLog(2)) { 043 meta.log("adding equals() hashCode() and _ebean_getIdentity() with Id field " 044 + idFieldMeta.getName()+ " index:" + idFieldIndex+" primitive:"+idFieldMeta.isPrimitiveType()); 045 } 046 if (idFieldMeta.isPrimitiveType()){ 047 addGetIdentityPrimitive(cv, meta, idFieldMeta); 048 } else { 049 addGetIdentityObject(cv, meta, idFieldIndex); 050 } 051 addEquals(cv, meta); 052 addHashCode(cv, meta); 053 } 054 055 } 056 057 /** 058 * The identity field used for implementing equals via the 059 * _ebean_getIdentity() method. 060 */ 061 public static void addIdentityField(ClassVisitor cv) { 062 063 int access = ACC_PROTECTED + ACC_TRANSIENT; 064 FieldVisitor f0 = cv.visitField(access, IDENTITY_FIELD, "Ljava/lang/Object;", null, null); 065 f0.visitEnd(); 066 } 067 068 /** 069 * Generate the _ebean_getIdentity method for primitive id types. 070 * <p> 071 * For primitives we need to check for == 0 rather than null. 072 * <p> 073 * <p> 074 * This is used for implementing equals(). 075 * <p> 076 * 077 * <pre> 078 * private Object _ebean_getIdentity() { 079 * synchronized (this) { 080 * if (_ebean_identity != null) { 081 * return _ebean_identity; 082 * } 083 * 084 * if (0 != getId()) { 085 * _ebean_identity = Integer.valueOf(getId()); 086 * } else { 087 * _ebean_identity = new Object(); 088 * } 089 * 090 * return _ebean_identity; 091 * } 092 * } 093 * </pre> 094 */ 095 private static void addGetIdentityPrimitive(ClassVisitor cv, ClassMeta classMeta, FieldMeta idFieldMeta) { 096 097 String className = classMeta.getClassName(); 098 099 MethodVisitor mv; 100 101 mv = cv.visitMethod(ACC_PRIVATE, _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", null, null); 102 mv.visitCode(); 103 Label l0 = new Label(); 104 Label l1 = new Label(); 105 Label l2 = new Label(); 106 mv.visitTryCatchBlock(l0, l1, l2, null); 107 Label l3 = new Label(); 108 Label l4 = new Label(); 109 mv.visitTryCatchBlock(l3, l4, l2, null); 110 Label l5 = new Label(); 111 mv.visitTryCatchBlock(l2, l5, l2, null); 112 Label l6 = new Label(); 113 mv.visitLabel(l6); 114 mv.visitLineNumber(1, l6); 115 mv.visitVarInsn(ALOAD, 0); 116 mv.visitInsn(DUP); 117 mv.visitVarInsn(ASTORE, 1); 118 mv.visitInsn(MONITORENTER); 119 mv.visitLabel(l0); 120 mv.visitLineNumber(1, l0); 121 mv.visitVarInsn(ALOAD, 0); 122 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 123 mv.visitJumpInsn(IFNULL, l3); 124 Label l7 = new Label(); 125 mv.visitLabel(l7); 126 mv.visitLineNumber(1, l7); 127 mv.visitVarInsn(ALOAD, 0); 128 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 129 mv.visitVarInsn(ALOAD, 1); 130 mv.visitInsn(MONITOREXIT); 131 mv.visitLabel(l1); 132 mv.visitInsn(ARETURN); 133 mv.visitLabel(l3); 134 mv.visitLineNumber(1, l3); 135 mv.visitFrame(Opcodes.F_APPEND, 1, new Object[]{"java/lang/Object"}, 0, null); 136 mv.visitVarInsn(ALOAD, 0); 137 idFieldMeta.appendGetPrimitiveIdValue(mv, classMeta); 138 idFieldMeta.appendCompare(mv, classMeta); 139 140 Label l8 = new Label(); 141 mv.visitJumpInsn(IFEQ, l8); 142 Label l9 = new Label(); 143 mv.visitLabel(l9); 144 mv.visitLineNumber(1, l9); 145 mv.visitVarInsn(ALOAD, 0); 146 mv.visitVarInsn(ALOAD, 0); 147 idFieldMeta.appendGetPrimitiveIdValue(mv, classMeta); 148 idFieldMeta.appendValueOf(mv); 149 mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 150 Label l10 = new Label(); 151 mv.visitJumpInsn(GOTO, l10); 152 mv.visitLabel(l8); 153 mv.visitLineNumber(1, l8); 154 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 155 mv.visitVarInsn(ALOAD, 0); 156 mv.visitTypeInsn(NEW, "java/lang/Object"); 157 mv.visitInsn(DUP); 158 mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false); 159 mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 160 mv.visitLabel(l10); 161 mv.visitLineNumber(1, l10); 162 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 163 mv.visitVarInsn(ALOAD, 0); 164 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 165 mv.visitVarInsn(ALOAD, 1); 166 mv.visitInsn(MONITOREXIT); 167 mv.visitLabel(l4); 168 mv.visitInsn(ARETURN); 169 mv.visitLabel(l2); 170 mv.visitLineNumber(1, l2); 171 mv.visitFrame(Opcodes.F_SAME1, 0, null, 1, new Object[]{"java/lang/Throwable"}); 172 mv.visitVarInsn(ASTORE, 2); 173 mv.visitVarInsn(ALOAD, 1); 174 mv.visitInsn(MONITOREXIT); 175 mv.visitLabel(l5); 176 mv.visitVarInsn(ALOAD, 2); 177 mv.visitInsn(ATHROW); 178 Label l11 = new Label(); 179 mv.visitLabel(l11); 180 mv.visitLocalVariable("this", "L"+className+";", null, l6, l11, 0); 181 mv.visitMaxs(4, 3); 182 mv.visitEnd(); 183 } 184 185 /** 186 * Generate the _ebean_getIdentity method for used with equals(). 187 * 188 * <pre> 189 * private Object _ebean_getIdentity() { 190 * synchronized (this) { 191 * if (_ebean_identity != null) { 192 * return _ebean_identity; 193 * } 194 * 195 * Object id = getId(); 196 * if (id != null) { 197 * _ebean_identity = id; 198 * } else { 199 * _ebean_identity = new Object(); 200 * } 201 * 202 * return _ebean_identity; 203 * } 204 * } 205 * </pre> 206 */ 207 private static void addGetIdentityObject(ClassVisitor cv, ClassMeta classMeta, int idFieldIndex) { 208 209 String className = classMeta.getClassName(); 210 211 MethodVisitor mv; 212 213 mv = cv.visitMethod(ACC_PRIVATE, _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", null, null); 214 mv.visitCode(); 215 Label l0 = new Label(); 216 Label l1 = new Label(); 217 Label l2 = new Label(); 218 mv.visitTryCatchBlock(l0, l1, l2, null); 219 Label l3 = new Label(); 220 Label l4 = new Label(); 221 mv.visitTryCatchBlock(l3, l4, l2, null); 222 Label l5 = new Label(); 223 mv.visitTryCatchBlock(l2, l5, l2, null); 224 Label l6 = new Label(); 225 mv.visitLabel(l6); 226 mv.visitLineNumber(1, l6); 227 mv.visitVarInsn(ALOAD, 0); 228 mv.visitInsn(DUP); 229 mv.visitVarInsn(ASTORE, 1); 230 mv.visitInsn(MONITORENTER); 231 mv.visitLabel(l0); 232 mv.visitLineNumber(1, l0); 233 mv.visitVarInsn(ALOAD, 0); 234 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 235 mv.visitJumpInsn(IFNULL, l3); 236 Label l7 = new Label(); 237 mv.visitLabel(l7); 238 mv.visitLineNumber(1, l7); 239 mv.visitVarInsn(ALOAD, 0); 240 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 241 mv.visitVarInsn(ALOAD, 1); 242 mv.visitInsn(MONITOREXIT); 243 mv.visitLabel(l1); 244 mv.visitInsn(ARETURN); 245 mv.visitLabel(l3); 246 mv.visitLineNumber(1, l3); 247 mv.visitFrame(Opcodes.F_APPEND, 1, new Object[]{"java/lang/Object"}, 0, null); 248 mv.visitVarInsn(ALOAD, 0); 249 VisitUtil.visitIntInsn(mv, idFieldIndex); 250 mv.visitMethodInsn(INVOKESPECIAL, className, "_ebean_getField", "(I)Ljava/lang/Object;", false); 251 mv.visitVarInsn(ASTORE, 2); 252 Label l8 = new Label(); 253 mv.visitLabel(l8); 254 mv.visitLineNumber(1, l8); 255 mv.visitVarInsn(ALOAD, 2); 256 Label l9 = new Label(); 257 mv.visitJumpInsn(IFNULL, l9); 258 Label l10 = new Label(); 259 mv.visitLabel(l10); 260 mv.visitLineNumber(1, l10); 261 mv.visitVarInsn(ALOAD, 0); 262 mv.visitVarInsn(ALOAD, 2); 263 mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 264 Label l11 = new Label(); 265 mv.visitJumpInsn(GOTO, l11); 266 mv.visitLabel(l9); 267 mv.visitLineNumber(1, l9); 268 mv.visitFrame(Opcodes.F_APPEND, 1, new Object[]{"java/lang/Object"}, 0, null); 269 mv.visitVarInsn(ALOAD, 0); 270 mv.visitTypeInsn(NEW, "java/lang/Object"); 271 mv.visitInsn(DUP); 272 mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false); 273 mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 274 mv.visitLabel(l11); 275 mv.visitLineNumber(1, l11); 276 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 277 mv.visitVarInsn(ALOAD, 0); 278 mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;"); 279 mv.visitVarInsn(ALOAD, 1); 280 mv.visitInsn(MONITOREXIT); 281 mv.visitLabel(l4); 282 mv.visitInsn(ARETURN); 283 mv.visitLabel(l2); 284 mv.visitLineNumber(1, l2); 285 mv.visitFrame(Opcodes.F_FULL, 2, new Object[]{className, "java/lang/Object"}, 1, new Object[]{"java/lang/Throwable"}); 286 mv.visitVarInsn(ASTORE, 3); 287 mv.visitVarInsn(ALOAD, 1); 288 mv.visitInsn(MONITOREXIT); 289 mv.visitLabel(l5); 290 mv.visitVarInsn(ALOAD, 3); 291 mv.visitInsn(ATHROW); 292 Label l12 = new Label(); 293 mv.visitLabel(l12); 294 mv.visitLocalVariable("this", "L"+className+";", null, l6, l12, 0); 295 mv.visitLocalVariable("tmpId", "Ljava/lang/Object;", null, l8, l2, 2); 296 mv.visitMaxs(3, 4); 297 mv.visitEnd(); 298 } 299 300 /** 301 * Generate the equals method. 302 * 303 * <pre> 304 * public boolean equals(Object o) { 305 * if (o == null) { 306 * return false; 307 * } 308 * if (!this.getClass().equals(o.getClass())) { 309 * return false; 310 * } 311 * if (o == this) { 312 * return true; 313 * } 314 * return _ebean_getIdentity().equals(((FooEntity)o)._ebean_getIdentity()); 315 * } 316 * </pre> 317 */ 318 private static void addEquals(ClassVisitor cv, ClassMeta classMeta) { 319 320 MethodVisitor mv; 321 322 mv = cv.visitMethod(ACC_PUBLIC, "equals", "(Ljava/lang/Object;)Z", null, null); 323 mv.visitCode(); 324 Label l0 = new Label(); 325 mv.visitLabel(l0); 326 mv.visitLineNumber(1, l0); 327 mv.visitVarInsn(ALOAD, 1); 328 Label l1 = new Label(); 329 mv.visitJumpInsn(IFNONNULL, l1); 330 Label l2 = new Label(); 331 mv.visitLabel(l2); 332 mv.visitLineNumber(2, l2); 333 mv.visitInsn(ICONST_0); 334 mv.visitInsn(IRETURN); 335 mv.visitLabel(l1); 336 mv.visitLineNumber(3, l1); 337 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 338 mv.visitVarInsn(ALOAD, 0); 339 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false); 340 mv.visitVarInsn(ALOAD, 1); 341 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false); 342 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false); 343 Label l3 = new Label(); 344 mv.visitJumpInsn(IFNE, l3); 345 Label l4 = new Label(); 346 mv.visitLabel(l4); 347 mv.visitLineNumber(4, l4); 348 mv.visitInsn(ICONST_0); 349 mv.visitInsn(IRETURN); 350 mv.visitLabel(l3); 351 mv.visitLineNumber(5, l3); 352 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 353 mv.visitVarInsn(ALOAD, 1); 354 mv.visitVarInsn(ALOAD, 0); 355 Label l5 = new Label(); 356 mv.visitJumpInsn(IF_ACMPNE, l5); 357 Label l6 = new Label(); 358 mv.visitLabel(l6); 359 mv.visitLineNumber(6, l6); 360 mv.visitInsn(ICONST_1); 361 mv.visitInsn(IRETURN); 362 mv.visitLabel(l5); 363 mv.visitLineNumber(7, l5); 364 mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null); 365 mv.visitVarInsn(ALOAD, 0); 366 mv.visitMethodInsn(INVOKEVIRTUAL, classMeta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false); 367 mv.visitVarInsn(ALOAD, 1); 368 mv.visitTypeInsn(CHECKCAST, classMeta.getClassName()); 369 mv.visitMethodInsn(INVOKEVIRTUAL, classMeta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false); 370 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false); 371 mv.visitInsn(IRETURN); 372 Label l7 = new Label(); 373 mv.visitLabel(l7); 374 mv.visitLocalVariable("this", "L"+classMeta.getClassName()+";", null, l0, l7, 0); 375 mv.visitLocalVariable("obj", "Ljava/lang/Object;", null, l0, l7, 1); 376 mv.visitMaxs(2, 2); 377 mv.visitEnd(); 378 } 379 380 /** 381 * Generate a hashCode method used to go with MethodEquals. 382 * 383 * <pre><code> 384 * public int hashCode() { 385 * return ebeanGetIdentity().hashCode(); 386 * } 387 * </code></pre> 388 */ 389 private static void addHashCode(ClassVisitor cv, ClassMeta meta) { 390 391 MethodVisitor mv; 392 393 mv = cv.visitMethod(ACC_PUBLIC, "hashCode", "()I", null, null); 394 mv.visitCode(); 395 Label l0 = new Label(); 396 mv.visitLabel(l0); 397 mv.visitLineNumber(1, l0); 398 mv.visitVarInsn(ALOAD, 0); 399 mv.visitMethodInsn(INVOKESPECIAL, meta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false); 400 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "hashCode", "()I", false); 401 mv.visitInsn(IRETURN); 402 Label l1 = new Label(); 403 mv.visitLabel(l1); 404 mv.visitLocalVariable("this", "L" + meta.getClassName() + ";", null, l0, l1, 0); 405 mv.visitMaxs(1, 1); 406 mv.visitEnd(); 407 408 } 409 410}