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/*
* #%L
* SciJava Common shared library for SciJava software.
* %%
* Copyright (C) 2009 - 2016 Board of Regents of the University of
* Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
* Institute of Molecular Cell Biology and Genetics.
* %%
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* #L%
*/
package org.scijava.util;
import java.io.File;
// Portions of this class were adapted from the
// org.apache.commons.lang3.reflect.TypeUtils and
// org.apache.commons.lang3.Validate classes of
// Apache Commons Lang 3.4, which is distributed
// under the Apache 2 license.
// See lines below starting with "BEGIN FORK OF APACHE COMMONS LANG".
//
// Portions of this class were adapted from the GenTyRef project
// by Wouter Coekaerts, which is distributed under the Apache 2 license.
// See lines below starting with "BEGIN FORK OF GENTYREF".
//
// See NOTICE.txt for further details on third-party licenses.
import java.io.Serializable;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.CodeSource;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import org.scijava.util.FileUtils;
/**
* Utility class for working with generic types, fields and methods.
* <p>
* Logic and inspiration were drawn from the following excellent libraries:
* </p>
* <ul>
* <li>Google Guava's {@code com.google.common.reflect} package.</li>
* <li>Apache Commons Lang 3's {@code org.apache.commons.lang3.reflect} package.
* </li>
* <li><a href="https://github.com/coekarts/gentyref">GenTyRef</a> (Generic Type
* Reflector), a library for runtime generic type introspection.</li>
* </ul>
*
* @author Curtis Rueden
*/
public final class Types {
private Types() {
// NB: Prevent instantiation of utility class.
}
/**
* Loads the class with the given name, using the current thread's context
* class loader, or null if it cannot be loaded.
*
* @param name The name of the class to load.
* @return The loaded class, or null if the class could not be loaded.
* @see #load(String, ClassLoader, boolean)
*/
public static Class<?> load(final String name) {
return load(name, null, true);
}
/**
* Loads the class with the given name, using the specified
* {@link ClassLoader}, or null if it cannot be loaded.
*
* @param name The name of the class to load.
* @param classLoader The class loader with which to load the class; if null,
* the current thread's context class loader will be used.
* @return The loaded class, or null if the class could not be loaded.
* @see #load(String, ClassLoader, boolean)
*/
public static Class<?> load(final String name,
final ClassLoader classLoader)
{
return load(name, classLoader, true);
}
/**
* Loads the class with the given name, using the current thread's context
* class loader.
*
* @param className the name of the class to load.
* @param quietly Whether to return {@code null} (rather than throwing
* {@link IllegalArgumentException}) if something goes wrong loading
* the class.
* @return The loaded class, or {@code null} if the class could not be loaded
* and the {@code quietly} flag is set.
* @see #load(String, ClassLoader, boolean)
* @throws IllegalArgumentException If the class cannot be loaded and the
* {@code quietly} flag is not set.
*/
public static Class<?> load(final String className, final boolean quietly) {
return load(className, null, quietly);
}
/**
* Loads the class with the given name, using the specified
* {@link ClassLoader}, or null if it cannot be loaded.
* <p>
* This method is capable of parsing several different class name syntaxes. In
* particular, array classes (including primitives) represented using either
* square brackets or internal Java array name syntax are supported. Examples:
* </p>
* <ul>
* <li>{@code boolean} is loaded as {@code boolean.class}</li>
* <li>{@code Z} is loaded as {@code boolean.class}</li>
* <li>{@code double[]} is loaded as {@code double[].class}</li>
* <li>{@code string[]} is loaded as {@code java.lang.String.class}</li>
* <li>{@code [F} is loaded as {@code float[].class}</li>
* </ul>
*
* @param name The name of the class to load.
* @param classLoader The class loader with which to load the class; if null,
* the current thread's context class loader will be used.
* @param quietly Whether to return {@code null} (rather than throwing
* {@link IllegalArgumentException}) if something goes wrong loading
* the class
* @return The loaded class, or {@code null} if the class could not be loaded
* and the {@code quietly} flag is set.
* @throws IllegalArgumentException If the class cannot be loaded and the
* {@code quietly} flag is not set.
*/
public static Class<?> load(final String name, final ClassLoader classLoader,
final boolean quietly)
{
// handle primitive types
if (name.equals("Z") || name.equals("boolean")) return boolean.class;
if (name.equals("B") || name.equals("byte")) return byte.class;
if (name.equals("C") || name.equals("char")) return char.class;
if (name.equals("D") || name.equals("double")) return double.class;
if (name.equals("F") || name.equals("float")) return float.class;
if (name.equals("I") || name.equals("int")) return int.class;
if (name.equals("J") || name.equals("long")) return long.class;
if (name.equals("S") || name.equals("short")) return short.class;
if (name.equals("V") || name.equals("void")) return void.class;
// handle built-in class shortcuts
final String className;
if (name.equals("string")) className = "java.lang.String";
else className = name;
// handle source style arrays (e.g.: "java.lang.String[]")
if (name.endsWith("[]")) {
final String elementClassName = name.substring(0, name.length() - 2);
return arrayOrNull(load(elementClassName, classLoader));
}
// handle non-primitive internal arrays (e.g.: "[Ljava.lang.String;")
if (name.startsWith("[L") && name.endsWith(";")) {
final String elementClassName = name.substring(2, name.length() - 1);
return arrayOrNull(load(elementClassName, classLoader));
}
// handle other internal arrays (e.g.: "[I", "[[I", "[[Ljava.lang.String;")
if (name.startsWith("[")) {
final String elementClassName = name.substring(1);
return arrayOrNull(load(elementClassName, classLoader));
}
// load the class!
try {
final ClassLoader cl = classLoader == null ? //
Thread.currentThread().getContextClassLoader() : classLoader;
return cl.loadClass(className);
}
catch (final Throwable t) {
// NB: Do not allow any failure to load the class to crash us.
// Not ClassNotFoundException.
// Not NoClassDefFoundError.
// Not UnsupportedClassVersionError!
if (quietly) return null;
throw iae(t, "Cannot load class: " + className);
}
}
/**
* Gets the base location of the given class.
*
* @param c The class whose location is desired.
* @return URL pointing to the class, or null if the location could not be
* determined.
* @see #location(Class, boolean)
*/
public static URL location(final Class<?> c) {
return location(c, true);
}
/**
* Gets the base location of the given class.
* <p>
* If the class is directly on the file system (e.g.,
* "/path/to/my/package/MyClass.class") then it will return the base directory
* (e.g., "file:/path/to").
* </p>
* <p>
* If the class is within a JAR file (e.g.,
* "/path/to/my-jar.jar!/my/package/MyClass.class") then it will return the
* path to the JAR (e.g., "file:/path/to/my-jar.jar").
* </p>
*
* @param c The class whose location is desired.
* @param quietly Whether to return {@code null} (rather than throwing
* {@link IllegalArgumentException}) if something goes wrong
* determining the location.
* @return URL pointing to the class, or null if the location could not be
* determined and the {@code quietly} flag is set.
* @throws IllegalArgumentException If the location cannot be determined and
* the {@code quietly} flag is not set.
* @see FileUtils#urlToFile(URL) to convert the result to a {@link File}.
*/
public static URL location(final Class<?> c, final boolean quietly) {
Exception cause = null;
String why = null;
// try the easy way first
try {
final CodeSource codeSource = c.getProtectionDomain().getCodeSource();
if (codeSource != null) {
final URL location = codeSource.getLocation();
if (location != null) return location;
why = "null code source location";
}
else why = "null code source";
}
catch (final SecurityException exc) {
// NB: Cannot access protection domain.
cause = exc;
why = "cannot access protection domain";
}
// NB: The easy way failed, so we try the hard way. We ask for the class
// itself as a resource, then strip the class's path from the URL string,
// leaving the base path.
// get the class's raw resource path
final URL classResource = c.getResource(c.getSimpleName() + ".class");
if (classResource == null) {
// cannot find class resource
if (quietly) return null;
throw iae(cause, "No class resource for class: " + name(c), why);
}
final String url = classResource.toString();
final String suffix = c.getCanonicalName().replace('.', '/') + ".class";
if (!url.endsWith(suffix)) {
// weird URL
if (quietly) return null;
throw iae(cause, "Unsupported URL format: " + url, why);
}
// strip the class's path from the URL string
final String base = url.substring(0, url.length() - suffix.length());
String path = base;
// remove the "jar:" prefix and "!/" suffix, if present
if (path.startsWith("jar:")) path = path.substring(4, path.length() - 2);
try {
return new URL(path);
}
catch (final MalformedURLException e) {
if (quietly) return null;
throw iae(e, "Malformed URL", why);
}
}
/**
* Gets a string representation of the given type.
*
* @param t Type whose name is desired.
* @return The name of the given type.
*/
public static String name(final Type t) {
if (t instanceof Class) {
final Class<?> c = (Class<?>) t;
return c.isArray() ? (name(component(c)) + "[]") : c.getName();
}
return t.toString();
}
/**
* Gets the (first) raw class of the given type.
* <ul>
* <li>If the type is a {@code Class} itself, the type itself is returned.
* </li>
* <li>If the type is a {@link ParameterizedType}, the raw type of the
* parameterized type is returned.</li>
* <li>If the type is a {@link GenericArrayType}, the returned type is the
* corresponding array class. For example: {@code List<Integer>[] => List[]}.
* </li>
* <li>If the type is a type variable or wildcard type, the raw type of the
* first upper bound is returned. For example:
* {@code <X extends Foo & Bar> => Foo}.</li>
* </ul>
* <p>
* If you want <em>all</em> raw classes of the given type, use {@link #raws}.
* </p>
*
* @param type The type from which to discern the (first) raw class.
* @return The type's first raw class.
*/
public static Class<?> raw(final Type type) {
if (type == null) return null;
if (type instanceof Class) return (Class<?>) type;
final List<Class<?>> c = raws(type);
if (c == null || c.size() == 0) return null;
return c.get(0);
}
/**
* Gets all raw classes corresponding to the given type.
* <p>
* For example, a type parameter {@code A extends Number & Iterable} will
* return both {@link Number} and {@link Iterable} as its raw classes.
* </p>
*
* @param type The type from which to discern the raw classes.
* @return List of the type's raw classes.
* @see #raw
*/
public static List<Class<?>> raws(final Type type) {
if (type == null) return null;
return GenericTypeReflector.getUpperBoundClassAndInterfaces(type);
}
public static boolean isBoolean(final Class<?> type) {
return type == boolean.class || Boolean.class.isAssignableFrom(type);
}
public static boolean isByte(final Class<?> type) {
return type == byte.class || Byte.class.isAssignableFrom(type);
}
public static boolean isCharacter(final Class<?> type) {
return type == char.class || Character.class.isAssignableFrom(type);
}
public static boolean isDouble(final Class<?> type) {
return type == double.class || Double.class.isAssignableFrom(type);
}
public static boolean isFloat(final Class<?> type) {
return type == float.class || Float.class.isAssignableFrom(type);
}
public static boolean isInteger(final Class<?> type) {
return type == int.class || Integer.class.isAssignableFrom(type);
}
public static boolean isLong(final Class<?> type) {
return type == long.class || Long.class.isAssignableFrom(type);
}
public static boolean isShort(final Class<?> type) {
return type == short.class || Short.class.isAssignableFrom(type);
}
public static boolean isNumber(final Class<?> type) {
return Number.class.isAssignableFrom(type) || type == byte.class ||
type == double.class || type == float.class || type == int.class ||
type == long.class || type == short.class;
}
public static boolean isText(final Class<?> type) {
return String.class.isAssignableFrom(type) || isCharacter(type);
}
/**
* Returns the non-primitive {@link Class} closest to the given type.
* <p>
* Specifically, the following type conversions are done:
* </p>
* <ul>
* <li>boolean.class becomes Boolean.class</li>
* <li>byte.class becomes Byte.class</li>
* <li>char.class becomes Character.class</li>
* <li>double.class becomes Double.class</li>
* <li>float.class becomes Float.class</li>
* <li>int.class becomes Integer.class</li>
* <li>long.class becomes Long.class</li>
* <li>short.class becomes Short.class</li>
* <li>void.class becomes Void.class</li>
* </ul>
* <p>
* All other types are unchanged.
* </p>
*/
public static <T> Class<T> box(final Class<T> type) {
final Class<?> destType;
if (type == boolean.class) destType = Boolean.class;
else if (type == byte.class) destType = Byte.class;
else if (type == char.class) destType = Character.class;
else if (type == double.class) destType = Double.class;
else if (type == float.class) destType = Float.class;
else if (type == int.class) destType = Integer.class;
else if (type == long.class) destType = Long.class;
else if (type == short.class) destType = Short.class;
else if (type == void.class) destType = Void.class;
else destType = type;
@SuppressWarnings("unchecked")
final Class<T> result = (Class<T>) destType;
return result;
}
/**
* Returns the primitive {@link Class} closest to the given type.
* <p>
* Specifically, the following type conversions are done:
* </p>
* <ul>
* <li>Boolean.class becomes boolean.class</li>
* <li>Byte.class becomes byte.class</li>
* <li>Character.class becomes char.class</li>
* <li>Double.class becomes double.class</li>
* <li>Float.class becomes float.class</li>
* <li>Integer.class becomes int.class</li>
* <li>Long.class becomes long.class</li>
* <li>Short.class becomes short.class</li>
* <li>Void.class becomes void.class</li>
* </ul>
* <p>
* All other types are unchanged.
* </p>
*/
public static <T> Class<T> unbox(final Class<T> type) {
final Class<?> destType;
if (type == Boolean.class) destType = boolean.class;
else if (type == Byte.class) destType = byte.class;
else if (type == Character.class) destType = char.class;
else if (type == Double.class) destType = double.class;
else if (type == Float.class) destType = float.class;
else if (type == Integer.class) destType = int.class;
else if (type == Long.class) destType = long.class;
else if (type == Short.class) destType = short.class;
else if (type == Void.class) destType = void.class;
else destType = type;
@SuppressWarnings("unchecked")
final Class<T> result = (Class<T>) destType;
return result;
}
/**
* Gets the "null" value for the given type. For non-primitives, this will
* actually be null. For primitives, it will be zero for numeric types, false
* for boolean, and the null character for char.
*/
public static <T> T nullValue(final Class<T> type) {
final Object defaultValue;
if (type == boolean.class) defaultValue = false;
else if (type == byte.class) defaultValue = (byte) 0;
else if (type == char.class) defaultValue = '\0';
else if (type == double.class) defaultValue = 0d;
else if (type == float.class) defaultValue = 0f;
else if (type == int.class) defaultValue = 0;
else if (type == long.class) defaultValue = 0L;
else if (type == short.class) defaultValue = (short) 0;
else defaultValue = null;
@SuppressWarnings("unchecked")
final T result = (T) defaultValue;
return result;
}
/**
* Gets the field with the specified name, of the given class, or superclass
* thereof.
* <p>
* Unlike {@link Class#getField(String)}, this method will return fields of
* any visibility, not just {@code public}. And unlike
* {@link Class#getDeclaredField(String)}, it will do so recursively,
* returning the first field of the given name from the class's superclass
* hierarchy.
* </p>
* <p>
* Note that this method does not guarantee that the returned field is
* accessible; if the field is not {@code public}, calling code will need to
* use {@link Field#setAccessible(boolean)} in order to manipulate the field's
* contents.
* </p>
*
* @param c The class (or subclass thereof) containing the desired field.
* @param name
* @return The first field with the given name in the class's superclass
* hierarchy.
* @throws IllegalArgumentException if the specified class does not contain a
* method with the given name
*/
public static Field field(final Class<?> c, final String name) {
if (c == null) throw iae("No such field: " + name);
try {
return c.getDeclaredField(name);
}
catch (final NoSuchFieldException e) {}
return field(c.getSuperclass(), name);
}
/**
* Gets the method with the specified name and argument types, of the given
* class, or superclass thereof.
* <p>
* Unlike {@link Class#getMethod(String, Class[])}, this method will return
* methods of any visibility, not just {@code public}. And unlike
* {@link Class#getDeclaredMethod(String, Class[])}, it will do so
* recursively, returning the first method of the given name and argument
* types from the class's superclass hierarchy.
* </p>
* <p>
* Note that this method does not guarantee that the returned method is
* accessible; if the method is not {@code public}, calling code will need to
* use {@link Method#setAccessible(boolean)} in order to invoke the method.
* </p>
*
* @param c The class (or subclass thereof) containing the desired method.
* @param name Name of the method.
* @param parameterTypes Types of the method parameters.
* @return The first method with the given name and argument types in the
* class's superclass hierarchy.
* @throws IllegalArgumentException If the specified class does not contain a
* method with the given name and argument types.
*/
public static Method method(final Class<?> c, final String name,
final Class<?>... parameterTypes)
{
if (c == null) throw iae("No such field: " + name);
try {
return c.getDeclaredMethod(name, parameterTypes);
}
catch (final NoSuchMethodException exc) {}
return method(c.getSuperclass(), name, parameterTypes);
}
/**
* Gets the array class corresponding to the given element type.
* <p>
* For example, {@code arrayType(double.class)} returns {@code double[].class}
* .
* </p>
*
* @param componentType The type of elements which the array possesses
* @throws IllegalArgumentException if the type cannot be the component type
* of an array (this is the case e.g. for {@code void.class}).
*/
public static Class<?> array(final Class<?> componentType) {
if (componentType == null) return null;
// NB: It appears the reflection API has no built-in way to do this.
// So unfortunately, we must allocate a new object and then inspect it.
return Array.newInstance(componentType, 0).getClass();
}
/**
* Gets the array class corresponding to the given element type and
* dimensionality.
* <p>
* For example, {@code arrayType(double.class, 2)} returns
* {@code double[][].class} .
* </p>
*
* @param componentType The type of elements which the array possesses
* @param dim The dimensionality of the array
*/
public static Class<?> array(final Class<?> componentType, final int dim) {
if (dim < 0) throw iae("Negative dimension");
if (dim == 0) return componentType;
return array(array(componentType), dim - 1);
}
/**
* Gets the array type—which might be a {@link Class} or a
* {@link GenericArrayType} depending on the argument—corresponding to
* the given element type.
* <p>
* For example, {@code arrayType(double.class)} returns {@code double[].class}
* .
* </p>
*
* @param componentType The type of elements which the array possesses
* @see #component
*/
public static Type array(final Type componentType) {
if (componentType == null) return null;
if (componentType instanceof Class) {
return array((Class<?>) componentType);
}
return new TypeUtils.GenericArrayTypeImpl(componentType);
}
/**
* Gets the component type of the given array type, or null if not an array.
* <p>
* If you have a {@link Class}, you can call {@link Class#getComponentType()}
* for a narrower return type.
* </p>
* <p>
* This is the opposite of {@link #array(Type)}.
* </p>
*/
public static Type component(final Type type) {
if (type instanceof Class) {
return ((Class<?>) type).getComponentType();
}
if (type instanceof GenericArrayType) {
return ((GenericArrayType) type).getGenericComponentType();
}
return null;
}
/**
* Returns the "safe" generic type of the given field, as viewed from the
* given type. This may be narrower than what {@link Field#getGenericType()}
* returns, if the field is declared in a superclass, or {@code type} has a
* type parameter that is used in the type of the field.
* <p>
* For example, suppose we have the following three classes:
* </p>
*
* <pre>
* public class Thing<T> {
*
* public T thing;
* }
*
* public class NumberThing<N extends Number> extends Thing<N> {}
*
* public class IntegerThing extends NumberThing<Integer> {}
* </pre>
*
* Then this method operates as follows:
*
* <pre>
* field = Types.field(Thing.class, "thing");
*
* field.getType(); // Object
* field.getGenericType(); // T
*
* Types.fieldType(field, Thing.class); // T
* Types.fieldType(field, NumberThing.class); // N extends Number
* Types.fieldType(field, IntegerThing.class); // Integer
* </pre>
*/
public static Type fieldType(final Field field, final Class<?> type) {
final Type wildType = GenericTypeReflector.addWildcardParameters(type);
return GenericTypeReflector.getExactFieldType(field, wildType);
}
/**
* As {@link #fieldType(Field, Class)}, but with respect to the return type of
* the given {@link Method} rather than a {@link Field}.
*/
public static Type methodReturnType(final Method method,
final Class<?> type)
{
final Type wildType = GenericTypeReflector.addWildcardParameters(type);
return GenericTypeReflector.getExactReturnType(method, wildType);
}
/**
* As {@link #fieldType(Field, Class)}, but with respect to the parameter
* types of the given {@link Method} rather than a {@link Field}.
*/
public static Type[] methodParamTypes(final Method method,
final Class<?> type)
{
final Type wildType = GenericTypeReflector.addWildcardParameters(type);
return GenericTypeReflector.getExactParameterTypes(method, wildType);
}
/**
* Gets the given type's {@code n}th type parameter of the specified class.
* <p>
* For example, with class {@code StringList implements List<String>},
* {@code Types.param(StringList.class, Collection.class, 0)} returns
* {@code String}.
* </p>
*/
public static Type param(final Type type, final Class<?> c, final int no) {
return GenericTypeReflector.getTypeParameter(type, //
c.getTypeParameters()[no]);
}
/**
* Discerns whether it would be legal to assign a reference of type
* {@code source} to a reference of type {@code target}.
*
* @param source The type from which assignment is desired.
* @param target The type to which assignment is desired.
* @return True if the source is assignable to the target.
* @throws NullPointerException if {@code target} is null.
* @see Class#isAssignableFrom(Class)
*/
public static boolean isAssignable(final Type source, final Type target) {
return TypeUtils.isAssignable(source, target);
}
/**
* Checks whether the given object can be cast to the specified type.
*
* @return true If the destination class is assignable from the source
* object's class, or if the source object is null and destination
* class is non-null.
* @see #cast(Object, Class)
*/
public static boolean isInstance(final Object obj, final Class<?> dest) {
if (dest == null) return false;
return obj == null || dest.isInstance(obj);
}
/**
* Casts the given object to the specified type, or null if the types are
* incompatible.
*/
public static <T> T cast(final Object src, final Class<T> dest) {
if (!isInstance(src, dest)) return null;
@SuppressWarnings("unchecked")
final T result = (T) src;
return result;
}
/**
* Converts the given string value to an enumeration constant of the specified
* type.
*
* @param name The value to convert.
* @param dest The type of the enumeration constant.
* @return The converted enumeration constant.
* @throws IllegalArgumentException if the type is not an enumeration type, or
* has no such constant.
*/
public static <T> T enumValue(final String name, final Class<T> dest) {
if (!dest.isEnum()) throw iae("Not an enum type: " + name(dest));
@SuppressWarnings({ "rawtypes", "unchecked" })
final Enum result = Enum.valueOf((Class) dest, name);
@SuppressWarnings("unchecked")
final T typedResult = (T) result;
return typedResult;
}
/**
* Creates a new {@link ParameterizedType} of the given class together with
* the specified type arguments.
*
* @param rawType The class of the {@link ParameterizedType}.
* @param typeArgs The type arguments to use in parameterizing it.
* @return The newly created {@link ParameterizedType}.
*/
public static ParameterizedType parameterize(final Class<?> rawType,
final Type... typeArgs)
{
return parameterize(rawType, rawType.getDeclaringClass(), typeArgs);
}
/**
* Creates a new {@link ParameterizedType} of the given class together with
* the specified type arguments.
*
* @param rawType The class of the {@link ParameterizedType}.
* @param ownerType The owner type of the parameterized class.
* @param typeArgs The type arguments to use in parameterizing it.
* @return The newly created {@link ParameterizedType}.
*/
public static ParameterizedType parameterize(final Class<?> rawType,
final Type ownerType, final Type... typeArgs)
{
return new TypeUtils.ParameterizedTypeImpl(rawType, ownerType, typeArgs);
}
/**
* Creates a new {@link WildcardType} with no upper or lower bounds (i.e.,
* {@code ?}).
*
* @return The newly created {@link WildcardType}.
*/
public static WildcardType wildcard() {
return wildcard((Type) null, (Type) null);
}
/**
* Creates a new {@link WildcardType} with the given upper and/or lower bound.
*
* @param upperBound Upper bound of the wildcard, or null for none.
* @param lowerBound Lower bound of the wildcard, or null for none.
* @return The newly created {@link WildcardType}.
*/
public static WildcardType wildcard(final Type upperBound,
final Type lowerBound)
{
return new TypeUtils.WildcardTypeImpl(upperBound, lowerBound);
}
/**
* Creates a new {@link WildcardType} with the given upper and/or lower
* bounds.
*
* @param upperBounds Upper bounds of the wildcard, or null for none.
* @param lowerBounds Lower bounds of the wildcard, or null for none.
* @return The newly created {@link WildcardType}.
*/
public static WildcardType wildcard(final Type[] upperBounds,
final Type[] lowerBounds)
{
return new TypeUtils.WildcardTypeImpl(upperBounds, lowerBounds);
}
/**
* Learn, recursively, whether any of the type parameters associated with
* {@code type} are bound to variables.
*
* @param type the type to check for type variables
* @return boolean
*/
public static boolean containsTypeVars(final Type type) {
return TypeUtils.containsTypeVariables(type);
}
/**
* Gets the type arguments of a class/interface based on a subtype. For
* instance, this method will determine that both of the parameters for the
* interface {@link Map} are {@link Object} for the subtype
* {@link java.util.Properties Properties} even though the subtype does not
* directly implement the {@code Map} interface.
* <p>
* This method returns {@code null} if {@code type} is not assignable to
* {@code toClass}. It returns an empty map if none of the classes or
* interfaces in its inheritance hierarchy specify any type arguments.
* </p>
* <p>
* A side effect of this method is that it also retrieves the type arguments
* for the classes and interfaces that are part of the hierarchy between
* {@code type} and {@code toClass}. So with the above example, this method
* will also determine that the type arguments for {@link java.util.Hashtable
* Hashtable} are also both {@code Object}. In cases where the interface
* specified by {@code toClass} is (indirectly) implemented more than once
* (e.g. where {@code toClass} specifies the interface
* {@link java.lang.Iterable Iterable} and {@code type} specifies a
* parameterized type that implements both {@link java.util.Set Set} and
* {@link java.util.Collection Collection}), this method will look at the
* inheritance hierarchy of only one of the implementations/subclasses; the
* first interface encountered that isn't a subinterface to one of the others
* in the {@code type} to {@code toClass} hierarchy.
* </p>
*
* @param type the type from which to determine the type parameters of
* {@code toClass}
* @param toClass the class whose type parameters are to be determined based
* on the subtype {@code type}
* @return a {@code Map} of the type assignments for the type variables in
* each type in the inheritance hierarchy from {@code type} to
* {@code toClass} inclusive.
*/
public static Map<TypeVariable<?>, Type> args(final Type type,
final Class<?> toClass)
{
return TypeUtils.getTypeArguments(type, toClass);
}
/**
* Tries to determine the type arguments of a class/interface based on a super
* parameterized type's type arguments. This method is the inverse of
* {@link #args(Type, Class)} which gets a class/interface's type arguments
* based on a subtype. It is far more limited in determining the type
* arguments for the subject class's type variables in that it can only
* determine those parameters that map from the subject {@link Class} object
* to the supertype.
* <p>
* Example: {@link java.util.TreeSet TreeSet} sets its parameter as the
* parameter for {@link java.util.NavigableSet NavigableSet}, which in turn
* sets the parameter of {@link java.util.SortedSet}, which in turn sets the
* parameter of {@link Set}, which in turn sets the parameter of
* {@link java.util.Collection}, which in turn sets the parameter of
* {@link java.lang.Iterable}. Since {@code TreeSet}'s parameter maps
* (indirectly) to {@code Iterable}'s parameter, it will be able to determine
* that based on the super type {@code Iterable<? extends
* Map<Integer, ? extends Collection<?>>>}, the parameter of {@code TreeSet}
* is {@code ? extends Map<Integer, ? extends Collection<?>>}.
* </p>
*
* @param c the class whose type parameters are to be determined, not
* {@code null}
* @param superType the super type from which {@code c}'s type arguments are
* to be determined, not {@code null}
* @return a {@code Map} of the type assignments that could be determined for
* the type variables in each type in the inheritance hierarchy from
* {@code type} to {@code c} inclusive.
*/
public static Map<TypeVariable<?>, Type> args(final Class<?> c,
final ParameterizedType superType)
{
return TypeUtils.determineTypeArguments(c, superType);
}
/**
* Create a parameterized type instance.
*
* @param raw the raw class to create a parameterized type instance for
* @param typeArgMappings the mapping used for parameterization
* @return {@link ParameterizedType}
*/
public static final ParameterizedType parameterize(final Class<?> raw,
final Map<TypeVariable<?>, Type> typeArgMappings)
{
return TypeUtils.parameterize(raw, typeArgMappings);
}
// -- Helper methods --
private static IllegalArgumentException iae(final String... s) {
return iae(null, s);
}
private static IllegalArgumentException iae(final Throwable cause,
final String... notes)
{
final String s = String.join(", ", notes);
final IllegalArgumentException exc = new IllegalArgumentException(s);
if (cause != null) exc.initCause(cause);
throw exc;
}
private static Class<?> arrayOrNull(final Class<?> componentType) {
try {
return Types.array(componentType);
}
catch (final IllegalArgumentException exc) {
return null;
}
}
// -- BEGIN FORK OF APACHE COMMONS LANG 3.4 CODE --
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* <p>
* Utility methods focusing on type inspection, particularly with regard to
* generics.
* </p>
*
* @since 3.0
* @version $Id: TypeUtils.java 1606051 2014-06-27 12:22:17Z ggregory $
*/