| /* |
| The MIT License |
| |
| Copyright (c) 2004-2015 Paul R. Holser, Jr. |
| |
| 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 joptsimple.internal; |
| |
| import java.lang.reflect.Constructor; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| |
| import static java.lang.reflect.Modifier.*; |
| |
| import joptsimple.ValueConverter; |
| |
| import static joptsimple.internal.Classes.*; |
| |
| /** |
| * Helper methods for reflection. |
| * |
| * @author <a href="mailto:pholser@alumni.rice.edu">Paul Holser</a> |
| */ |
| public final class Reflection { |
| private Reflection() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Finds an appropriate value converter for the given class. |
| * |
| * @param <V> a constraint on the class object to introspect |
| * @param clazz class to introspect on |
| * @return a converter method or constructor |
| */ |
| public static <V> ValueConverter<V> findConverter( Class<V> clazz ) { |
| Class<V> maybeWrapper = wrapperOf( clazz ); |
| |
| ValueConverter<V> valueOf = valueOfConverter( maybeWrapper ); |
| if ( valueOf != null ) |
| return valueOf; |
| |
| ValueConverter<V> constructor = constructorConverter( maybeWrapper ); |
| if ( constructor != null ) |
| return constructor; |
| |
| throw new IllegalArgumentException( clazz + " is not a value type" ); |
| } |
| |
| private static <V> ValueConverter<V> valueOfConverter( Class<V> clazz ) { |
| try { |
| Method valueOf = clazz.getMethod( "valueOf", String.class ); |
| if ( meetsConverterRequirements( valueOf, clazz ) ) |
| return new MethodInvokingValueConverter<>( valueOf, clazz ); |
| |
| return null; |
| } catch ( NoSuchMethodException ignored ) { |
| return null; |
| } |
| } |
| |
| private static <V> ValueConverter<V> constructorConverter( Class<V> clazz ) { |
| try { |
| return new ConstructorInvokingValueConverter<>( clazz.getConstructor( String.class ) ); |
| } catch ( NoSuchMethodException ignored ) { |
| return null; |
| } |
| } |
| |
| /** |
| * Invokes the given constructor with the given arguments. |
| * |
| * @param <T> constraint on the type of the objects yielded by the constructor |
| * @param constructor constructor to invoke |
| * @param args arguments to hand to the constructor |
| * @return the result of invoking the constructor |
| * @throws ReflectionException in lieu of the gaggle of reflection-related exceptions |
| */ |
| public static <T> T instantiate( Constructor<T> constructor, Object... args ) { |
| try { |
| return constructor.newInstance( args ); |
| } catch ( Exception ex ) { |
| throw reflectionException( ex ); |
| } |
| } |
| |
| /** |
| * Invokes the given static method with the given arguments. |
| * |
| * @param method method to invoke |
| * @param args arguments to hand to the method |
| * @return the result of invoking the method |
| * @throws ReflectionException in lieu of the gaggle of reflection-related exceptions |
| */ |
| public static Object invoke( Method method, Object... args ) { |
| try { |
| return method.invoke( null, args ); |
| } catch ( Exception ex ) { |
| throw reflectionException( ex ); |
| } |
| } |
| |
| @SuppressWarnings( "unchecked" ) |
| public static <V> V convertWith( ValueConverter<V> converter, String raw ) { |
| return converter == null ? (V) raw : converter.convert( raw ); |
| } |
| |
| private static boolean meetsConverterRequirements( Method method, Class<?> expectedReturnType ) { |
| int modifiers = method.getModifiers(); |
| return isPublic( modifiers ) && isStatic( modifiers ) && expectedReturnType.equals( method.getReturnType() ); |
| } |
| |
| private static RuntimeException reflectionException( Exception ex ) { |
| if ( ex instanceof IllegalArgumentException ) |
| return new ReflectionException( ex ); |
| if ( ex instanceof InvocationTargetException ) |
| return new ReflectionException( ex.getCause() ); |
| if ( ex instanceof RuntimeException ) |
| return (RuntimeException) ex; |
| |
| return new ReflectionException( ex ); |
| } |
| } |