aboutsummaryrefslogtreecommitdiff
path: root/src/core/lombok/javac/handlers/JavacHandlerUtil.java
blob: 3f869410db48e840c23edfd905c1f25914cc803b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
/*
 * Copyright © 2009-2010 Reinier Zwitserloot, Roel Spilker and Robbert Jan Grootjans.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.javac.handlers;

import static lombok.javac.Javac.annotationTypeMatches;

import java.lang.annotation.Annotation;
import java.util.regex.Pattern;

import lombok.AccessLevel;
import lombok.Data;
import lombok.Getter;
import lombok.core.AnnotationValues;
import lombok.core.AST.Kind;
import lombok.core.handlers.TransformationsUtil;
import lombok.javac.Javac;
import lombok.javac.JavacNode;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.TypeTags;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCLiteral;
import com.sun.tools.javac.tree.JCTree.JCModifiers;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCAssign;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCIdent;
import com.sun.tools.javac.tree.JCTree.JCImport;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
import com.sun.tools.javac.tree.JCTree.JCNewArray;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Name;

/**
 * Container for static utility methods useful to handlers written for javac.
 */
public class JavacHandlerUtil {
	private JavacHandlerUtil() {
		//Prevent instantiation
	}
	
	/**
	 * Checks if the given expression (that really ought to refer to a type expression) represents a primitive type.
	 */
	public static boolean isPrimitive(JCExpression ref) {
		String typeName = ref.toString();
		return TransformationsUtil.PRIMITIVE_TYPE_NAME_PATTERN.matcher(typeName).matches();
	}
	
	/**
	 * Removes the annotation from javac's AST (it remains in lombok's AST),
	 * then removes any import statement that imports this exact annotation (not star imports).
	 * Only does this if the DeleteLombokAnnotations class is in the context.
	 */
	public static void markAnnotationAsProcessed(JavacNode annotation, Class<? extends Annotation> annotationType) {
		if (!annotation.shouldDeleteLombokAnnotations()) return;
		JavacNode parentNode = annotation.directUp();
		switch (parentNode.getKind()) {
		case FIELD:
		case ARGUMENT:
		case LOCAL:
			JCVariableDecl variable = (JCVariableDecl) parentNode.get();
			variable.mods.annotations = filterList(variable.mods.annotations, annotation.get());
			break;
		case METHOD:
			JCMethodDecl method = (JCMethodDecl) parentNode.get();
			method.mods.annotations = filterList(method.mods.annotations, annotation.get());
			break;
		case TYPE:
			try {
				JCClassDecl type = (JCClassDecl) parentNode.get();
				type.mods.annotations = filterList(type.mods.annotations, annotation.get());
			} catch (ClassCastException e) {
				//something rather odd has been annotated. Better to just break only delombok instead of everything.
			}
			break;
		default:
			//This really shouldn't happen, but if it does, better just break delombok instead of breaking everything.
			return;
		}
		
		deleteImportFromCompilationUnit(annotation, annotationType.getName());
	}
	
	public static void deleteImportFromCompilationUnit(JavacNode node, String name) {
		if (!node.shouldDeleteLombokAnnotations()) return;
		ListBuffer<JCTree> newDefs = ListBuffer.lb();
		
		JCCompilationUnit unit = (JCCompilationUnit) node.top().get();
		
		for (JCTree def : unit.defs) {
			boolean delete = false;
			if (def instanceof JCImport) {
				JCImport imp0rt = (JCImport)def;
				delete = (!imp0rt.staticImport && imp0rt.qualid.toString().equals(name));
			}
			if (!delete) newDefs.append(def);
		}
		unit.defs = newDefs.toList();
	}

	private static List<JCAnnotation> filterList(List<JCAnnotation> annotations, JCTree jcTree) {
		ListBuffer<JCAnnotation> newAnnotations = ListBuffer.lb();
		for (JCAnnotation ann : annotations) {
			if (jcTree != ann) newAnnotations.append(ann);
		}
		return newAnnotations.toList();
	}
	
	/**
	 * Translates the given field into all possible getter names.
	 * Convenient wrapper around {@link TransformationsUtil#toAllGetterNames(CharSequence, boolean)}.
	 */
	public static java.util.List<String> toAllGetterNames(JCVariableDecl field) {
		CharSequence fieldName = field.name;
		
		boolean isBoolean = field.vartype.toString().equals("boolean");
		
		return TransformationsUtil.toAllGetterNames(fieldName, isBoolean);
	}
	
	/**
	 * @return the likely getter name for the stated field. (e.g. private boolean foo; to isFoo).
	 * 
	 * Convenient wrapper around {@link TransformationsUtil#toGetterName(CharSequence, boolean)}.
	 */
	public static String toGetterName(JCVariableDecl field) {
		CharSequence fieldName = field.name;
		
		boolean isBoolean = field.vartype.toString().equals("boolean");
		
		return TransformationsUtil.toGetterName(fieldName, isBoolean);
	}
	
	/**
	 * @return the likely setter name for the stated field. (e.g. private boolean foo; to setFoo).
	 * 
	 * Convenient wrapper around {@link TransformationsUtil#toSetterName(CharSequence)}.
	 */
	public static String toSetterName(JCVariableDecl field) {
		CharSequence fieldName = field.name;
		
		return TransformationsUtil.toSetterName(fieldName);
	}
	
	/** Serves as return value for the methods that check for the existence of fields and methods. */
	public enum MemberExistsResult {
		NOT_EXISTS, EXISTS_BY_USER, EXISTS_BY_LOMBOK;
	}
	
	/**
	 * Checks if there is a field with the provided name.
	 * 
	 * @param fieldName the field name to check for.
	 * @param node Any node that represents the Type (JCClassDecl) to look in, or any child node thereof.
	 */
	public static MemberExistsResult fieldExists(String fieldName, JavacNode node) {
		while (node != null && !(node.get() instanceof JCClassDecl)) {
			node = node.up();
		}
		
		if (node != null && node.get() instanceof JCClassDecl) {
			for (JCTree def : ((JCClassDecl)node.get()).defs) {
				if (def instanceof JCVariableDecl) {
					if (((JCVariableDecl)def).name.contentEquals(fieldName)) {
						JavacNode existing = node.getNodeFor(def);
						if (existing == null || !existing.isHandled()) return MemberExistsResult.EXISTS_BY_USER;
						return MemberExistsResult.EXISTS_BY_LOMBOK;
					}
				}
			}
		}
		
		return MemberExistsResult.NOT_EXISTS;
	}
	
	public static MemberExistsResult methodExists(String methodName, JavacNode node) {
		return methodExists(methodName, node, true);
	}
	
	/**
	 * Checks if there is a method with the provided name. In case of multiple methods (overloading), only
	 * the first method decides if EXISTS_BY_USER or EXISTS_BY_LOMBOK is returned.
	 * 
	 * @param methodName the method name to check for.
	 * @param node Any node that represents the Type (JCClassDecl) to look in, or any child node thereof.
	 * @param caseSensitive If the search should be case sensitive.
	 */
	public static MemberExistsResult methodExists(String methodName, JavacNode node, boolean caseSensitive) {
		while (node != null && !(node.get() instanceof JCClassDecl)) {
			node = node.up();
		}
		
		if (node != null && node.get() instanceof JCClassDecl) {
			for (JCTree def : ((JCClassDecl)node.get()).defs) {
				if (def instanceof JCMethodDecl) {
					String name = ((JCMethodDecl)def).name.toString();
					boolean matches = caseSensitive ? name.equals(methodName) : name.equalsIgnoreCase(methodName);
					if (matches) {
						JavacNode existing = node.getNodeFor(def);
						if (existing == null || !existing.isHandled()) return MemberExistsResult.EXISTS_BY_USER;
						return MemberExistsResult.EXISTS_BY_LOMBOK;
					}
				}
			}
		}
		
		return MemberExistsResult.NOT_EXISTS;
	}
	
	/**
	 * Checks if there is a (non-default) constructor. In case of multiple constructors (overloading), only
	 * the first constructor decides if EXISTS_BY_USER or EXISTS_BY_LOMBOK is returned.
	 * 
	 * @param node Any node that represents the Type (JCClassDecl) to look in, or any child node thereof.
	 */
	public static MemberExistsResult constructorExists(JavacNode node) {
		while (node != null && !(node.get() instanceof JCClassDecl)) {
			node = node.up();
		}
		
		if (node != null && node.get() instanceof JCClassDecl) {
			for (JCTree def : ((JCClassDecl)node.get()).defs) {
				if (def instanceof JCMethodDecl) {
					if (((JCMethodDecl)def).name.contentEquals("<init>")) {
						if ((((JCMethodDecl)def).mods.flags & Flags.GENERATEDCONSTR) != 0) continue;
						JavacNode existing = node.getNodeFor(def);
						if (existing == null || !existing.isHandled()) return MemberExistsResult.EXISTS_BY_USER;
						return MemberExistsResult.EXISTS_BY_LOMBOK;
					}
				}
			}
		}
		
		return MemberExistsResult.NOT_EXISTS;
	}
	
	/**
	 * Turns an {@code AccessLevel} instance into the flag bit used by javac.
	 */
	public static int toJavacModifier(AccessLevel accessLevel) {
		switch (accessLevel) {
		case MODULE:
		case PACKAGE:
			return 0;
		default:
		case PUBLIC:
			return Flags.PUBLIC;
		case NONE:
		case PRIVATE:
			return Flags.PRIVATE;
		case PROTECTED:
			return Flags.PROTECTED;
		}
	}
	
	private static class GetterMethod {
		private final Name name;
		private final JCExpression type;
		
		GetterMethod(Name name, JCExpression type) {
			this.name = name;
			this.type = type;
		}
	}
	
	private static GetterMethod findGetter(JavacNode field) {
		JCVariableDecl decl = (JCVariableDecl)field.get();
		JavacNode typeNode = field.up();
		for (String potentialGetterName : toAllGetterNames(decl)) {
			switch (methodExists(potentialGetterName, typeNode, false)) {
			case EXISTS_BY_LOMBOK:
			case EXISTS_BY_USER:
				for (JavacNode potentialGetter : typeNode.down()) {
					if (potentialGetter.getKind() != Kind.METHOD) continue;
					JCMethodDecl method = (JCMethodDecl) potentialGetter.get();
					if (!method.name.contentEquals(potentialGetterName)) continue;
					/** static getX() methods don't count. */
					if ((method.mods.flags & Flags.STATIC) != 0) continue;
					/** Nor do getters with a non-empty parameter list. */
					if (method.params != null && method.params.size() > 0) continue;
					return new GetterMethod(method.name, method.restype);
				}
			}
		}
		
		// Check if the field has a @Getter annotation.
		
		boolean hasGetterAnnotation = false;
		
		for (JavacNode child : field.down()) {
			if (child.getKind() == Kind.ANNOTATION && annotationTypeMatches(Getter.class, child)) {
				AnnotationValues<Getter> ann = Javac.createAnnotation(Getter.class, child);
				if (ann.getInstance().value() == AccessLevel.NONE) return null;   //Definitely WONT have a getter.
				hasGetterAnnotation = true;
			}
		}
		
		// Check if the class has a @Getter annotation.
		
		if (!hasGetterAnnotation && new HandleGetter().fieldQualifiesForGetterGeneration(field)) {
			//Check if the class has @Getter or @Data annotation.
			
			JavacNode containingType = field.up();
			if (containingType != null) for (JavacNode child : containingType.down()) {
				if (child.getKind() == Kind.ANNOTATION && annotationTypeMatches(Data.class, child)) hasGetterAnnotation = true;
				if (child.getKind() == Kind.ANNOTATION && annotationTypeMatches(Getter.class, child)) {
					AnnotationValues<Getter> ann = Javac.createAnnotation(Getter.class, child);
					if (ann.getInstance().value() == AccessLevel.NONE) return null;   //Definitely WONT have a getter.
					hasGetterAnnotation = true;
				}
			}
		}
		
		if (hasGetterAnnotation) {
			String getterName = toGetterName(decl);
			return new GetterMethod(field.toName(getterName), decl.vartype);
		}
		
		return null;
	}
	
	enum FieldAccess {
		GETTER, PREFER_FIELD, ALWAYS_FIELD;
	}
	
	static boolean lookForGetter(JavacNode field, FieldAccess fieldAccess) {
		if (fieldAccess == FieldAccess.GETTER) return true;
		if (fieldAccess == FieldAccess.ALWAYS_FIELD) return false;
		
		// If @Getter(lazy = true) is used, then using it is mandatory.
		for (JavacNode child : field.down()) {
			if (child.getKind() != Kind.ANNOTATION) continue;
			if (Javac.annotationTypeMatches(Getter.class, child)) {
				AnnotationValues<Getter> ann = Javac.createAnnotation(Getter.class, child);
				if (ann.getInstance().lazy()) return true;
			}
		}
		return false;
	}
	
	/**
	 * Returns the type of the field, unless a getter exists for this field, in which case the return type of the getter is returned.
	 * 
	 * @see #createFieldAccessor(TreeMaker, JavacNode)
	 */
	static JCExpression getFieldType(JavacNode field, FieldAccess fieldAccess) {
		boolean lookForGetter = lookForGetter(field, fieldAccess);
		
		GetterMethod getter = lookForGetter ? findGetter(field) : null;
		
		if (getter == null) {
			return ((JCVariableDecl)field.get()).vartype;
		}
		
		return getter.type;
	}
	
	/**
	 * Creates an expression that reads the field. Will either be {@code this.field} or {@code this.getField()} depending on whether or not there's a getter.
	 */
	static JCExpression createFieldAccessor(TreeMaker maker, JavacNode field, FieldAccess fieldAccess) {
		return createFieldAccessor(maker, field, fieldAccess, null);
	}
	
	static JCExpression createFieldAccessor(TreeMaker maker, JavacNode field, FieldAccess fieldAccess, JCExpression receiver) {
		boolean lookForGetter = lookForGetter(field, fieldAccess);
		
		GetterMethod getter = lookForGetter ? findGetter(field) : null;
		JCVariableDecl fieldDecl = (JCVariableDecl) field.get();
		
		if (getter == null) {
			if (receiver == null) {
				if ((fieldDecl.mods.flags & Flags.STATIC) == 0) {
					receiver = maker.Ident(field.toName("this"));
				} else {
					JavacNode containerNode = field.up();
					if (containerNode != null && containerNode.get() instanceof JCClassDecl) {
						JCClassDecl container = (JCClassDecl) field.up().get();
						receiver = maker.Ident(container.name);
					}
				}
			}
			
			return receiver == null ? maker.Ident(fieldDecl.name) : maker.Select(receiver, fieldDecl.name);
		}
		
		if (receiver == null) receiver = maker.Ident(field.toName("this"));
		JCMethodInvocation call = maker.Apply(List.<JCExpression>nil(),
				maker.Select(receiver, getter.name), List.<JCExpression>nil());
		return call;
	}
	
	/**
	 * Adds the given new field declaration to the provided type AST Node.
	 * The field carries the &#64;{@link SuppressWarnings}("all") annotation.
	 * Also takes care of updating the JavacAST.
	 */
	public static void injectFieldSuppressWarnings(JavacNode typeNode, JCVariableDecl field) {
		injectField(typeNode, field, true);
	}
	
	/**
	 * Adds the given new field declaration to the provided type AST Node.
	 * 
	 * Also takes care of updating the JavacAST.
	 */
	public static void injectField(JavacNode typeNode, JCVariableDecl field) {
		injectField(typeNode, field, false);
	}

	private static void injectField(JavacNode typeNode, JCVariableDecl field, boolean addSuppressWarnings) {
		JCClassDecl type = (JCClassDecl) typeNode.get();
		
		if (addSuppressWarnings) addSuppressWarningsAll(field.mods, typeNode, field.pos);
		type.defs = type.defs.append(field);
		
		typeNode.add(field, Kind.FIELD).recursiveSetHandled();
	}
	
	/**
	 * Adds the given new method declaration to the provided type AST Node.
	 * Can also inject constructors.
	 * 
	 * Also takes care of updating the JavacAST.
	 */
	public static void injectMethod(JavacNode typeNode, JCMethodDecl method) {
		JCClassDecl type = (JCClassDecl) typeNode.get();
		
		if (method.getName().contentEquals("<init>")) {
			//Scan for default constructor, and remove it.
			int idx = 0;
			for (JCTree def : type.defs) {
				if (def instanceof JCMethodDecl) {
					if ((((JCMethodDecl)def).mods.flags & Flags.GENERATEDCONSTR) != 0) {
						JavacNode tossMe = typeNode.getNodeFor(def);
						if (tossMe != null) tossMe.up().removeChild(tossMe);
						type.defs = addAllButOne(type.defs, idx);
						break;
					}
				}
				idx++;
			}
		}
		
		addSuppressWarningsAll(method.mods, typeNode, method.pos);
		type.defs = type.defs.append(method);
		
		typeNode.add(method, Kind.METHOD).recursiveSetHandled();
	}
	
	private static void addSuppressWarningsAll(JCModifiers mods, JavacNode node, int pos) {
		TreeMaker maker = node.getTreeMaker();
		JCExpression suppressWarningsType = chainDots(maker, node, "java", "lang", "SuppressWarnings");
		JCLiteral allLiteral = maker.Literal("all");
		suppressWarningsType.pos = pos;
		allLiteral.pos = pos;
		JCAnnotation annotation = maker.Annotation(suppressWarningsType, List.<JCExpression>of(allLiteral));
		annotation.pos = pos;
		mods.annotations = mods.annotations.append(annotation);
	}
	
	private static List<JCTree> addAllButOne(List<JCTree> defs, int idx) {
		ListBuffer<JCTree> out = ListBuffer.lb();
		int i = 0;
		for (JCTree def : defs) {
			if (i++ != idx) out.append(def);
		}
		return out.toList();
	}
	
	/**
	 * In javac, dotted access of any kind, from {@code java.lang.String} to {@code var.methodName}
	 * is represented by a fold-left of {@code Select} nodes with the leftmost string represented by
	 * a {@code Ident} node. This method generates such an expression.
	 * 
	 * For example, maker.Select(maker.Select(maker.Ident(NAME[java]), NAME[lang]), NAME[String]).
	 * 
	 * @see com.sun.tools.javac.tree.JCTree.JCIdent
	 * @see com.sun.tools.javac.tree.JCTree.JCFieldAccess
	 */
	public static JCExpression chainDots(TreeMaker maker, JavacNode node, String... elems) {
		assert elems != null;
		assert elems.length > 0;
		
		JCExpression e = maker.Ident(node.toName(elems[0]));
		for (int i = 1 ; i < elems.length ; i++) {
			e = maker.Select(e, node.toName(elems[i]));
		}
		
		return e;
	}

	
	/**
	 * In javac, dotted access of any kind, from {@code java.lang.String} to {@code var.methodName}
	 * is represented by a fold-left of {@code Select} nodes with the leftmost string represented by
	 * a {@code Ident} node. This method generates such an expression.
	 * 
	 * For example, maker.Select(maker.Select(maker.Ident(NAME[java]), NAME[lang]), NAME[String]).
	 * 
	 * @see com.sun.tools.javac.tree.JCTree.JCIdent
	 * @see com.sun.tools.javac.tree.JCTree.JCFieldAccess
	 */
	public static JCExpression chainDotsString(TreeMaker maker, JavacNode node, String elems) {
		return chainDots(maker, node, elems.split("\\."));	
	}
	
	/**
	 * Searches the given field node for annotations and returns each one that matches the provided regular expression pattern.
	 * 
	 * Only the simple name is checked - the package and any containing class are ignored.
	 */
	public static List<JCAnnotation> findAnnotations(JavacNode fieldNode, Pattern namePattern) {
		ListBuffer<JCAnnotation> result = ListBuffer.lb();
		for (JavacNode child : fieldNode.down()) {
			if (child.getKind() == Kind.ANNOTATION) {
				JCAnnotation annotation = (JCAnnotation) child.get();
				String name = annotation.annotationType.toString();
				int idx = name.lastIndexOf(".");
				String suspect = idx == -1 ? name : name.substring(idx + 1);
				if (namePattern.matcher(suspect).matches()) {
					result.append(annotation);
				}
			}
		}	
		return result.toList();
	}
	
	/**
	 * Generates a new statement that checks if the given variable is null, and if so, throws a {@code NullPointerException} with the
	 * variable name as message.
	 */
	public static JCStatement generateNullCheck(TreeMaker treeMaker, JavacNode variable) {
		JCVariableDecl varDecl = (JCVariableDecl) variable.get();
		if (isPrimitive(varDecl.vartype)) return null;
		Name fieldName = varDecl.name;
		JCExpression npe = chainDots(treeMaker, variable, "java", "lang", "NullPointerException");
		JCTree exception = treeMaker.NewClass(null, List.<JCExpression>nil(), npe, List.<JCExpression>of(treeMaker.Literal(fieldName.toString())), null);
		JCStatement throwStatement = treeMaker.Throw(exception);
		return treeMaker.If(treeMaker.Binary(JCTree.EQ, treeMaker.Ident(fieldName), treeMaker.Literal(TypeTags.BOT, null)), throwStatement, null);
	}
	
	/**
	 * Given a list of field names and a node referring to a type, finds each name in the list that does not match a field within the type.
	 */
	public static List<Integer> createListOfNonExistentFields(List<String> list, JavacNode type, boolean excludeStandard, boolean excludeTransient) {
		boolean[] matched = new boolean[list.size()];
		
		for (JavacNode child : type.down()) {
			if (list.isEmpty()) break;
			if (child.getKind() != Kind.FIELD) continue;
			JCVariableDecl field = (JCVariableDecl)child.get();
			if (excludeStandard) {
				if ((field.mods.flags & Flags.STATIC) != 0) continue;
				if (field.name.toString().startsWith("$")) continue;
			}
			if (excludeTransient && (field.mods.flags & Flags.TRANSIENT) != 0) continue;
			
			int idx = list.indexOf(child.getName());
			if (idx > -1) matched[idx] = true;
		}
		
		ListBuffer<Integer> problematic = ListBuffer.lb();
		for (int i = 0 ; i < list.size() ; i++) {
			if (!matched[i]) problematic.append(i);
		}
		
		return problematic.toList();
	}
	
	static List<JCExpression> getAndRemoveAnnotationParameter(JCAnnotation ast, String parameterName) {
		ListBuffer<JCExpression> params = ListBuffer.lb();
		List<JCExpression> result = List.nil();
		
		for (JCExpression param : ast.args) {
			if (param instanceof JCAssign) {
				JCAssign assign = (JCAssign) param;
				if (assign.lhs instanceof JCIdent) {
					JCIdent ident = (JCIdent) assign.lhs;
					if (parameterName.equals(ident.name.toString())) {
						if (assign.rhs instanceof JCNewArray) {
							result = ((JCNewArray) assign.rhs).elems;
						} else {
							result = result.append(assign.rhs);
						}
						continue;
					}
				}
			}
			
			params.append(param);
		}
		ast.args = params.toList();
		return result;
	}
	
	static List<JCAnnotation> copyAnnotations(List<JCExpression> in) {
		ListBuffer<JCAnnotation> out = ListBuffer.lb();
		for (JCExpression expr : in) {
			if (!(expr instanceof JCAnnotation)) continue;
			out.append((JCAnnotation) expr.clone());
		}
		return out.toList();
	}
}