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 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 ClassDesc} would have an array rank of greater than 255
152 * @jvms 4.4.1 The CONSTANT_Class_info Structure
153 */
154 default ClassDesc arrayType() {
155 int depth = ConstantUtils.arrayDepth(descriptorString());
156 if (depth >= ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
157 throw new IllegalStateException(
158 "Cannot create an array type descriptor with more than " +
159 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
160 }
161 return arrayType(1);
162 }
163
235 */
236 default boolean isArray() {
237 return descriptorString().startsWith("[");
238 }
239
240 /**
241 * Returns whether this {@linkplain ClassDesc} describes a primitive type.
242 *
243 * @return whether this {@linkplain ClassDesc} describes a primitive type
244 */
245 default boolean isPrimitive() {
246 return descriptorString().length() == 1;
247 }
248
249 /**
250 * Returns whether this {@linkplain ClassDesc} describes a class or interface type.
251 *
252 * @return whether this {@linkplain ClassDesc} describes a class or interface type
253 */
254 default boolean isClassOrInterface() {
255 return descriptorString().startsWith("L");
256 }
257
258 /**
259 * Returns the component type of this {@linkplain ClassDesc}, if it describes
260 * an array type, or {@code null} otherwise.
261 *
262 * @return a {@linkplain ClassDesc} describing the component type, or {@code null}
263 * if this descriptor does not describe an array type
264 */
265 default ClassDesc componentType() {
266 return isArray() ? ClassDesc.ofDescriptor(descriptorString().substring(1)) : null;
267 }
268
269 /**
270 * Returns the package name of this {@linkplain ClassDesc}, if it describes
271 * a class or interface type.
272 *
273 * @return the package name, or the empty string if the class is in the
274 * default package, or this {@linkplain ClassDesc} does not describe a class or interface type
275 */
|
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 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 ClassDesc} would have an array rank of greater than 255
155 * @jvms 4.4.1 The CONSTANT_Class_info Structure
156 */
157 default ClassDesc arrayType() {
158 int depth = ConstantUtils.arrayDepth(descriptorString());
159 if (depth >= ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
160 throw new IllegalStateException(
161 "Cannot create an array type descriptor with more than " +
162 ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS + " dimensions");
163 }
164 return arrayType(1);
165 }
166
238 */
239 default boolean isArray() {
240 return descriptorString().startsWith("[");
241 }
242
243 /**
244 * Returns whether this {@linkplain ClassDesc} describes a primitive type.
245 *
246 * @return whether this {@linkplain ClassDesc} describes a primitive type
247 */
248 default boolean isPrimitive() {
249 return descriptorString().length() == 1;
250 }
251
252 /**
253 * Returns whether this {@linkplain ClassDesc} describes a class or interface type.
254 *
255 * @return whether this {@linkplain ClassDesc} describes a class or interface type
256 */
257 default boolean isClassOrInterface() {
258 return descriptorString().startsWith("L") || descriptorString().startsWith("Q");
259 }
260
261 /**
262 * Returns whether this {@linkplain ClassDesc} describes a
263 * {@linkplain Class#isValueType() primitive value type}.
264 *
265 * @return whether this {@linkplain ClassDesc} describes a primitive value type.
266 * @since Valhalla
267 */
268 default boolean isValueType() {
269 return descriptorString().startsWith("Q");
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 */
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