40 * A <a href="package-summary.html#nominal">nominal descriptor</a> for a
41 * {@link Class} constant.
42 *
43 * <p>For common system types, including all the primitive types, there are
44 * predefined {@linkplain ClassDesc} constants in {@link ConstantDescs}.
45 * (The {@code java.lang.constant} APIs consider {@code void} to be a primitive type.)
46 * To create a {@linkplain ClassDesc} for a class or interface type, use {@link #of} or
47 * {@link #ofDescriptor(String)}; to create a {@linkplain ClassDesc} for an array
48 * type, use {@link #ofDescriptor(String)}, or first obtain a
49 * {@linkplain ClassDesc} for the component type and then call the {@link #arrayType()}
50 * or {@link #arrayType(int)} methods.
51 *
52 * @see ConstantDescs
53 *
54 * @since 12
55 */
56 public sealed interface ClassDesc
57 extends ConstantDesc,
58 TypeDescriptor.OfField<ClassDesc>
59 permits PrimitiveClassDescImpl,
60 ReferenceClassDescImpl {
61
62 /**
63 * Returns a {@linkplain ClassDesc} for a class or interface type,
64 * given the name of the class or interface, such as {@code "java.lang.String"}.
65 * (To create a descriptor for an array type, either use {@link #ofDescriptor(String)}
66 * or {@link #arrayType()}; to create a descriptor for a primitive type, use
67 * {@link #ofDescriptor(String)} or use the predefined constants in
68 * {@link ConstantDescs}).
69 *
70 * @param name the fully qualified (dot-separated) binary class name
71 * @return a {@linkplain ClassDesc} describing the desired class
72 * @throws NullPointerException if the argument is {@code null}
73 * @throws IllegalArgumentException if the name string is not in the
74 * correct format
75 */
76 static ClassDesc of(String name) {
77 ConstantUtils.validateBinaryClassName(requireNonNull(name));
78 return ClassDesc.ofDescriptor("L" + binaryToInternal(name) + ";");
79 }
80
81 /**
82 * Returns a {@linkplain ClassDesc} for a class or interface type,
83 * given a package name and the unqualified (simple) name for the
84 * class or interface.
85 *
86 * @param packageName the package name (dot-separated); if the package
87 * name is the empty string, the class is considered to
88 * be in the unnamed package
93 * not in the correct format
94 */
95 static ClassDesc of(String packageName, String className) {
96 ConstantUtils.validateBinaryClassName(requireNonNull(packageName));
97 if (packageName.isEmpty()) {
98 return of(className);
99 }
100 validateMemberName(requireNonNull(className), false);
101 return ofDescriptor("L" + binaryToInternal(packageName) +
102 "/" + className + ";");
103 }
104
105 /**
106 * Returns a {@linkplain ClassDesc} given a descriptor string for a class,
107 * interface, array, or primitive type.
108 *
109 * @apiNote
110 *
111 * A field type descriptor string for a non-array type is either
112 * a one-letter code corresponding to a primitive type
113 * ({@code "J", "I", "C", "S", "B", "D", "F", "Z", "V"}), or the letter {@code "L"}, followed
114 * by the fully qualified binary name of a class, followed by {@code ";"}.
115 * A field type descriptor for an array type is the character {@code "["}
116 * followed by the field descriptor for the component type. Examples of
117 * valid type descriptor strings include {@code "Ljava/lang/String;"}, {@code "I"},
118 * {@code "[I"}, {@code "V"}, {@code "[Ljava/lang/String;"}, etc.
119 * See JVMS {@jvms 4.3.2 }("Field Descriptors") for more detail.
120 *
121 * @param descriptor a field descriptor string
122 * @return a {@linkplain ClassDesc} describing the desired class
123 * @throws NullPointerException if the argument is {@code null}
124 * @throws IllegalArgumentException if the name string is not in the
125 * correct format
126 * @jvms 4.3.2 Field Descriptors
127 * @jvms 4.4.1 The CONSTANT_Class_info Structure
128 */
129 static ClassDesc ofDescriptor(String descriptor) {
130 requireNonNull(descriptor);
131 if (descriptor.isEmpty()) {
132 throw new IllegalArgumentException(
133 "not a valid reference type descriptor: " + descriptor);
134 }
135 int depth = ConstantUtils.arrayDepth(descriptor);
136 if (depth > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
137 throw new IllegalArgumentException(
138 "Cannot create an array type descriptor with more than " +
139 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
140 }
141 return (descriptor.length() == 1)
142 ? new PrimitiveClassDescImpl(descriptor)
143 : new ReferenceClassDescImpl(descriptor);
144 }
145
146 /**
147 * Returns a {@linkplain ClassDesc} for an array type whose component type
148 * is described by this {@linkplain ClassDesc}.
149 *
150 * @return a {@linkplain ClassDesc} describing the array type
151 * @throws IllegalStateException if the resulting {@linkplain
152 * ClassDesc} would have an array rank of greater than 255
153 * @jvms 4.4.1 The CONSTANT_Class_info Structure
154 */
155 default ClassDesc arrayType() {
156 int depth = ConstantUtils.arrayDepth(descriptorString());
157 if (depth >= ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
158 throw new IllegalStateException(
159 "Cannot create an array type descriptor with more than " +
160 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
161 }
162 return arrayType(1);
163 }
249 */
250 default boolean isArray() {
251 return descriptorString().startsWith("[");
252 }
253
254 /**
255 * Returns whether this {@linkplain ClassDesc} describes a primitive type.
256 *
257 * @return whether this {@linkplain ClassDesc} describes a primitive type
258 */
259 default boolean isPrimitive() {
260 return descriptorString().length() == 1;
261 }
262
263 /**
264 * Returns whether this {@linkplain ClassDesc} describes a class or interface type.
265 *
266 * @return whether this {@linkplain ClassDesc} describes a class or interface type
267 */
268 default boolean isClassOrInterface() {
269 return descriptorString().startsWith("L");
270 }
271
272 /**
273 * Returns the component type of this {@linkplain ClassDesc}, if it describes
274 * an array type, or {@code null} otherwise.
275 *
276 * @return a {@linkplain ClassDesc} describing the component type, or {@code null}
277 * if this descriptor does not describe an array type
278 */
279 default ClassDesc componentType() {
280 return isArray() ? ClassDesc.ofDescriptor(descriptorString().substring(1)) : null;
281 }
282
283 /**
284 * Returns the package name of this {@linkplain ClassDesc}, if it describes
285 * a class or interface type.
286 *
287 * @return the package name, or the empty string if the class is in the
288 * default package, or this {@linkplain ClassDesc} does not describe a class or interface type
289 */
|
40 * A <a href="package-summary.html#nominal">nominal descriptor</a> for a
41 * {@link Class} constant.
42 *
43 * <p>For common system types, including all the primitive types, there are
44 * predefined {@linkplain ClassDesc} constants in {@link ConstantDescs}.
45 * (The {@code java.lang.constant} APIs consider {@code void} to be a primitive type.)
46 * To create a {@linkplain ClassDesc} for a class or interface type, use {@link #of} or
47 * {@link #ofDescriptor(String)}; to create a {@linkplain ClassDesc} for an array
48 * type, use {@link #ofDescriptor(String)}, or first obtain a
49 * {@linkplain ClassDesc} for the component type and then call the {@link #arrayType()}
50 * or {@link #arrayType(int)} methods.
51 *
52 * @see ConstantDescs
53 *
54 * @since 12
55 */
56 public sealed interface ClassDesc
57 extends ConstantDesc,
58 TypeDescriptor.OfField<ClassDesc>
59 permits PrimitiveClassDescImpl,
60 ClassDescImpl {
61
62 /**
63 * Returns a {@linkplain ClassDesc} for a class or interface type,
64 * given the name of the class or interface, such as {@code "java.lang.String"}.
65 * (To create a descriptor for an array type, either use {@link #ofDescriptor(String)}
66 * or {@link #arrayType()}; to create a descriptor for a primitive type, use
67 * {@link #ofDescriptor(String)} or use the predefined constants in
68 * {@link ConstantDescs}; to create a descriptor for a primitive value type,
69 * use {@link #ofDescriptor(String)}).
70 *
71 * @param name the fully qualified (dot-separated) binary class name
72 * @return a {@linkplain ClassDesc} describing the desired class
73 * @throws NullPointerException if the argument is {@code null}
74 * @throws IllegalArgumentException if the name string is not in the
75 * correct format
76 */
77 static ClassDesc of(String name) {
78 ConstantUtils.validateBinaryClassName(requireNonNull(name));
79 return ClassDesc.ofDescriptor("L" + binaryToInternal(name) + ";");
80 }
81
82 /**
83 * Returns a {@linkplain ClassDesc} for a class or interface type,
84 * given a package name and the unqualified (simple) name for the
85 * class or interface.
86 *
87 * @param packageName the package name (dot-separated); if the package
88 * name is the empty string, the class is considered to
89 * be in the unnamed package
94 * not in the correct format
95 */
96 static ClassDesc of(String packageName, String className) {
97 ConstantUtils.validateBinaryClassName(requireNonNull(packageName));
98 if (packageName.isEmpty()) {
99 return of(className);
100 }
101 validateMemberName(requireNonNull(className), false);
102 return ofDescriptor("L" + binaryToInternal(packageName) +
103 "/" + className + ";");
104 }
105
106 /**
107 * Returns a {@linkplain ClassDesc} given a descriptor string for a class,
108 * interface, array, or primitive type.
109 *
110 * @apiNote
111 *
112 * A field type descriptor string for a non-array type is either
113 * a one-letter code corresponding to a primitive type
114 * ({@code "J", "I", "C", "S", "B", "D", "F", "Z", "V"}),
115 * or the letter {@code "L"} or {@code "Q"} followed
116 * by the fully qualified binary name of a class, followed by {@code ";"}.
117 * A field type descriptor for an array type is the character {@code "["}
118 * followed by the field descriptor for the component type. Examples of
119 * valid type descriptor strings include {@code "Ljava/lang/String;"},
120 * {@code "QPoint;}, {@code "I"}, {@code "[I"}, {@code "V"},
121 * {@code "[Ljava/lang/String;"}, {@code "[LPoint;"}, {@code "[[QPoint;} etc.
122 * See JVMS {@jvms 4.3.2 }("Field Descriptors") for more detail.
123 *
124 * @param descriptor a field descriptor string
125 * @return a {@linkplain ClassDesc} describing the desired class
126 * @throws NullPointerException if the argument is {@code null}
127 * @throws IllegalArgumentException if the name string is not in the
128 * correct format
129 * @jvms 4.3.2 Field Descriptors
130 * @jvms 4.4.1 The CONSTANT_Class_info Structure
131 */
132 static ClassDesc ofDescriptor(String descriptor) {
133 requireNonNull(descriptor);
134 if (descriptor.isEmpty()) {
135 throw new IllegalArgumentException(
136 "not a valid reference type descriptor: " + descriptor);
137 }
138 int depth = ConstantUtils.arrayDepth(descriptor);
139 if (depth > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
140 throw new IllegalArgumentException(
141 "Cannot create an array type descriptor with more than " +
142 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
143 }
144 return (descriptor.length() == 1)
145 ? new PrimitiveClassDescImpl(descriptor)
146 : new ClassDescImpl(descriptor);
147 }
148
149 /**
150 * Returns a {@linkplain ClassDesc} for an array type whose component type
151 * is described by this {@linkplain ClassDesc}.
152 *
153 * @return a {@linkplain ClassDesc} describing the array type
154 * @throws IllegalStateException if the resulting {@linkplain
155 * ClassDesc} would have an array rank of greater than 255
156 * @jvms 4.4.1 The CONSTANT_Class_info Structure
157 */
158 default ClassDesc arrayType() {
159 int depth = ConstantUtils.arrayDepth(descriptorString());
160 if (depth >= ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
161 throw new IllegalStateException(
162 "Cannot create an array type descriptor with more than " +
163 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
164 }
165 return arrayType(1);
166 }
252 */
253 default boolean isArray() {
254 return descriptorString().startsWith("[");
255 }
256
257 /**
258 * Returns whether this {@linkplain ClassDesc} describes a primitive type.
259 *
260 * @return whether this {@linkplain ClassDesc} describes a primitive type
261 */
262 default boolean isPrimitive() {
263 return descriptorString().length() == 1;
264 }
265
266 /**
267 * Returns whether this {@linkplain ClassDesc} describes a class or interface type.
268 *
269 * @return whether this {@linkplain ClassDesc} describes a class or interface type
270 */
271 default boolean isClassOrInterface() {
272 return descriptorString().startsWith("L") || descriptorString().startsWith("Q");
273 }
274
275 /**
276 * Returns whether this {@linkplain ClassDesc} describes a
277 * {@linkplain Class#isPrimitiveValueType() primitive value type}.
278 *
279 * @return whether this {@linkplain ClassDesc} describes a primitive value type.
280 * @since Valhalla
281 */
282 default boolean isPrimitiveValueType() {
283 return descriptorString().startsWith("Q");
284 }
285
286 /**
287 * Returns the component type of this {@linkplain ClassDesc}, if it describes
288 * an array type, or {@code null} otherwise.
289 *
290 * @return a {@linkplain ClassDesc} describing the component type, or {@code null}
291 * if this descriptor does not describe an array type
292 */
293 default ClassDesc componentType() {
294 return isArray() ? ClassDesc.ofDescriptor(descriptorString().substring(1)) : null;
295 }
296
297 /**
298 * Returns the package name of this {@linkplain ClassDesc}, if it describes
299 * a class or interface type.
300 *
301 * @return the package name, or the empty string if the class is in the
302 * default package, or this {@linkplain ClassDesc} does not describe a class or interface type
303 */
|