Java Reflection Generic Type from Field getGenericTypes(Field field)

Description

get Generic Types

License

Apache License

Declaration

public static Set<Class> getGenericTypes(Field field) 

Method Source Code

//package com.java2s;
/*-/*from  w w  w  . jav a 2s .c  o  m*/
 * Plantuml builder
 *
 * Copyright (C) 2017 Focus IT
 *
 * 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.
 */

import java.lang.reflect.*;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Main {
    public static Set<Class> getGenericTypes(ParameterizedType type) {
        return Stream.of(type.getActualTypeArguments()).filter(Class.class::isInstance).map(Class.class::cast)
                .collect(Collectors.toSet());
    }

    public static Set<Class> getGenericTypes(Field field) {
        if (field.getGenericType() instanceof ParameterizedType) {
            // manage generics
            return getGenericTypes((ParameterizedType) field.getGenericType());
        }
        return new HashSet<>();
    }

    public static Set<Class> getGenericTypes(Method method) {
        if (method.getGenericReturnType() instanceof ParameterizedType) {
            // manage generics
            return getGenericTypes((ParameterizedType) method.getGenericReturnType());
        }
        return new HashSet<>();
    }

    public static Set<Class> getGenericTypes(Parameter parameter) {
        if (parameter.getParameterizedType() instanceof ParameterizedType) {
            // manage generics
            return getGenericTypes((ParameterizedType) parameter.getParameterizedType());
        }
        return new HashSet<>();
    }
}

Related

1. getGenericType(Field field)
2. getGenericType(Type type, Type fieldType)
3. getGenericTypeArguments(final Field field)
4. getGenericTypeOfCollectionField(Field field)
5. getGenericTypes(Field field)
6. getGenericTypes(Field field)
7. getGenericTypes(Field field)
8. getGenericTypes(Field field)