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package org.jtheque.utils; |
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import java.lang.reflect.Array; |
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import java.lang.reflect.GenericArrayType; |
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import java.lang.reflect.GenericDeclaration; |
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import java.lang.reflect.ParameterizedType; |
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import java.lang.reflect.Type; |
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import java.lang.reflect.TypeVariable; |
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import java.util.ArrayList; |
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import java.util.Collection; |
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import java.util.HashMap; |
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import java.util.Map; |
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public final class GenericsUtils { |
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private GenericsUtils() { |
41 | 0 | super(); |
42 | 0 | } |
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public static <T> Collection<Class<?>> getTypeArguments(final Class<T> baseClass, |
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final Type childClass) { |
55 | 0 | Map<Type, Type> resolvedTypes = new HashMap<Type, Type>(10); |
56 | 0 | Type type = childClass; |
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58 | 0 | while (!getClass(type).equals(baseClass)) { |
59 | 0 | if (type instanceof Class) { |
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62 | 0 | type = ((Class<?>) type).getGenericSuperclass(); |
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} else { |
64 | 0 | ParameterizedType parameterizedType = (ParameterizedType) type; |
65 | 0 | Class<?> rawType = (Class<?>) parameterizedType.getRawType(); |
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67 | 0 | Type[] actualTypeArguments = parameterizedType.getActualTypeArguments(); |
68 | 0 | TypeVariable<?>[] typeParameters = rawType.getTypeParameters(); |
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70 | 0 | for (int i = 0; i < actualTypeArguments.length; i++) { |
71 | 0 | resolvedTypes.put(typeParameters[i], actualTypeArguments[i]); |
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} |
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74 | 0 | if (!rawType.equals(baseClass)) { |
75 | 0 | type = rawType.getGenericSuperclass(); |
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} |
77 | 0 | } |
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} |
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80 | 0 | return determineRawClasses(resolvedTypes, type); |
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} |
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private static Collection<Class<?>> determineRawClasses(Map<Type, Type> resolvedTypes, Type type) { |
91 | 0 | Type[] actualTypeArguments = type instanceof Class ? ((GenericDeclaration) type).getTypeParameters() : ((ParameterizedType) type).getActualTypeArguments(); |
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93 | 0 | Collection<Class<?>> typeArgumentsAsClasses = new ArrayList<Class<?>>(actualTypeArguments.length); |
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95 | 0 | for (Type baseType : actualTypeArguments) { |
96 | 0 | while (resolvedTypes.containsKey(baseType)) { |
97 | 0 | baseType = resolvedTypes.get(baseType); |
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} |
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100 | 0 | typeArgumentsAsClasses.add(getClass(baseType)); |
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} |
102 | 0 | return typeArgumentsAsClasses; |
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} |
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private static Class<?> getClass(Type type) { |
113 | 0 | Class<?> typeClass = null; |
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115 | 0 | if (type instanceof Class) { |
116 | 0 | typeClass = (Class<?>) type; |
117 | 0 | } else if (type instanceof ParameterizedType) { |
118 | 0 | typeClass = getClass(((ParameterizedType) type).getRawType()); |
119 | 0 | } else if (type instanceof GenericArrayType) { |
120 | 0 | Type componentType = ((GenericArrayType) type).getGenericComponentType(); |
121 | 0 | Class<?> componentClass = getClass(componentType); |
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123 | 0 | if (componentClass != null) { |
124 | 0 | typeClass = Array.newInstance(componentClass, 0).getClass(); |
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} |
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} |
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128 | 0 | return typeClass; |
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} |
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} |