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GeezerVison is showing github.com — scyjava/src/scyjava/_types.py at main · scijava/scyjava Expand file tree/ Copy path_types.pyMore file actions 339 lines (260 loc) · 10.3 KB / Copy path_types.pyFile metadata and controls339 lines (260 loc) · 10.3 KB 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 """ Utility functions for working with and reasoning about Java types. """ from collections.abc import Callable, Sequence from typing import Any import jpype from scyjava._jvm import jimport, jvm_started, start_jvm from scyjava.config import Mode, mode class JavaClasses: """ Utility class used to make importing frequently-used Java classes significantly easier and more readable. Benefits: * Minimal boilerplate * Lazy evaluation * Usable within type hints Example: from scyjava import JavaClasses class MyJavaClasses(JavaClasses): @JavaClasses.java_import def String(self): return "java.lang.String" @JavaClasses.java_import def Integer(self): return "java.lang.Integer" # ... and many more ... jc = MyJavaClasses() def parse_number_with_java(s: "jc.String") -> "jc.Integer": return jc.Integer.parseInt(s) """ def java_import(func: Callable[[], str]) -> property: """ A decorator used to lazily evaluate a java import. func is a function of a Python class that takes no arguments and returns a string identifying a Java class by name. Using that function, this decorator creates a property that when called, imports the class identified by the function. """ @property def inner(self): if not jvm_started(): raise RuntimeError("The JVM has not been started yet.") try: return jimport(func(self)) except TypeError: return None return inner def jclass(data): """ Obtain a Java class object. Supported types include: A. Name of a class to look up -- e.g. "java.lang.String" -- which returns the equivalent of Class.forName("java.lang.String"). B. A static-style class reference -- e.g. String -- which returns the equivalent of String.class. C. A Java object -- e.g. foo -- which returns the equivalent of foo.getClass(). Note that if you pass a java.lang.Class object, you will get back Class.class, i.e. the Java class for the Class class. :-) :param data: The object from which to glean the class. :return: A java.lang.Class object, suitable for use with reflection. :raise TypeError: if the argument is not one of the aforementioned types. """ if isinstance(data, str): # Name of a class -- case (A) above. return jclass(jimport(data)) if mode == Mode.JPYPE: start_jvm() if isinstance(data, jpype.JClass): # JPype object representing a static-style class -- case (B) above. return data.class_ elif mode == Mode.JEP: if str(type(data.getClass())) == "<class 'jep.PyJClass'>": # Jep object representing a static-style class -- case (B) above. raise ValueError( "Jep does not support Java class objects " + "-- see https://github.com/ninia/jep/issues/405" ) # A Java object -- case (C) above. if jinstance(data, "java.lang.Object"): return data.getClass() raise TypeError("Cannot glean class from data of type: " + str(type(data))) def jstacktrace(exc) -> str: """ Extract the Java-side stack trace from a Java exception. Example of usage: from scyjava import jimport, jstacktrace try: Integer = jimport('java.lang.Integer') nan = Integer.parseInt('not a number') except Exception as exc: print(jstacktrace(exc)) :param exc: The Java Throwable from which to extract the stack trace. :return: A multi-line string containing the stack trace, or empty string if no stack trace could be extracted. """ try: StringWriter = jimport("java.io.StringWriter") PrintWriter = jimport("java.io.PrintWriter") sw = StringWriter() exc.printStackTrace(PrintWriter(sw, True)) return str(sw) except BaseException: # noqa: BLE001 return "" def isjava(data) -> bool: """Return whether the given data object is a Java object.""" if mode == Mode.JEP: return jinstance(data, "java.lang.Object") assert mode == Mode.JPYPE return isinstance(data, (jpype.JClass, jpype.JObject)) def is_jbyte(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Byte") def is_jshort(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Short") def is_jinteger(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Integer") def is_jlong(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Long") def is_jfloat(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Float") def is_jdouble(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Double") def is_jboolean(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Boolean") def is_jcharacter(the_type: type) -> bool: return _is_jtype(the_type, "java.lang.Character") def is_jarray(data: Any) -> bool: """Return whether the given data object is a Java array.""" if mode == Mode.JEP: return str(type(data)) == "<class 'jep.PyJArray'>" assert mode == Mode.JPYPE return isinstance(data, jpype.JArray) def jinstance(obj, jtype) -> bool: """ Test if the given object is an instance of a particular Java type. :param obj: The object to check. :param jtype: The Java type, as either a jimported class or as a string. :return: True iff the object is an instance of that Java type. """ if isinstance(jtype, str): jtype = jimport(jtype) if mode == Mode.JEP: return isinstance(obj, jtype.__pytype__) assert mode == Mode.JPYPE return isinstance(obj, jtype) def jarray(kind, lengths: Sequence): """ Create a new n-dimensional Java array. :param kind: The type of array to create. This can either be a particular type of object as obtained from jimport, or else a special code for one of the eight primitive array types: * 'b' for byte * 'c' for char * 'd' for double * 'f' for float * 'i' for int * 'j' for long * 's' for short * 'z' for boolean :param lengths: List of lengths for the array. For example: `jarray('z', [3, 7])` is the equivalent of `new boolean[3][7]` in Java. You can pass a single integer to make a 1-dimensional array of that length. :return: The newly allocated array """ if isinstance(kind, str): kind = kind.lower() if isinstance(lengths, int): lengths = [lengths] arraytype = kind if mode == Mode.JEP: import jep if len(lengths) == 1: # Fast case: 1-d array (we can use primitives) arr = jep.jarray(lengths[0], arraytype) else: # Slow case: n-d array (we cannot use primitives) # See https://github.com/ninia/jep/issues/439 kinds = { "b": jimport("java.lang.Byte"), "c": jimport("java.lang.Character"), "d": jimport("java.lang.Double"), "f": jimport("java.lang.Float"), "i": jimport("java.lang.Integer"), "j": jimport("java.lang.Long"), "s": jimport("java.lang.Short"), "z": jimport("java.lang.Boolean"), } if arraytype in kinds: arraytype = kinds[arraytype] kind = arraytype # build up the array type for _ in range(len(lengths) - 1): arraytype = jep.jarray(0, arraytype) # instantiate the n-dimensional array arr = jep.jarray(lengths[0], arraytype) elif mode == Mode.JPYPE: start_jvm() # build up the array type kinds = { "b": jpype.JByte, "c": jpype.JChar, "d": jpype.JDouble, "f": jpype.JFloat, "i": jpype.JInt, "j": jpype.JLong, "s": jpype.JShort, "z": jpype.JBoolean, } if arraytype in kinds: arraytype = kinds[arraytype] for _ in range(len(lengths)): arraytype = jpype.JArray(arraytype) # instantiate the n-dimensional array arr = arraytype(lengths[0]) else: raise RuntimeError(f"Invalid mode: {mode}") if len(lengths) > 1: for i in range(len(arr)): arr[i] = jarray(kind, lengths[1:]) return arr def numeric_bounds( the_type: type, ) -> tuple[int, int] | tuple[float, float] | tuple[None, None]: """ Get the minimum and maximum values for the given numeric type. For example, a Java long returns (int(Long.MIN_VALUE), int(Long.MAX_VALUE)), whereas a Java double returns (float(-Double.MAX_VALUE), float(Double.MAX_VALUE)). :param the_type: The type whose minimum and maximum values are needed. :return: The minimum and maximum values as a two-element tuple of int or float, or a two-element tuple of None if no known bounds. """ if is_jbyte(the_type): Byte = jimport("java.lang.Byte") return int(Byte.MIN_VALUE), int(Byte.MAX_VALUE) if is_jshort(the_type): Short = jimport("java.lang.Short") return int(Short.MIN_VALUE), int(Short.MAX_VALUE) if is_jinteger(the_type): Integer = jimport("java.lang.Integer") return int(Integer.MIN_VALUE), int(Integer.MAX_VALUE) if is_jlong(the_type): Long = jimport("java.lang.Long") return int(Long.MIN_VALUE), int(Long.MAX_VALUE) if is_jfloat(the_type): Float = jimport("java.lang.Float") return float(-Float.MAX_VALUE), float(Float.MAX_VALUE) if is_jdouble(the_type): Double = jimport("java.lang.Double") return float(-Double.MAX_VALUE), float(Double.MAX_VALUE) return None, None def _is_jtype(the_type: type, class_name: str) -> bool: """ Test if the given type object is *exactly* the specified Java type. :param the_type: The type object to check. :param class_name: The fully qualified Java class name in string form. :return: True iff the type is exactly that Java type. """ # NB: Stringify the type to support both bridge modes. Ex: # * JPype: <java class 'java.lang.Integer'> # * Jep: <class 'java.lang.Integer'> return f"class '{class_name}'" in str(the_type) |
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