Java Reflection Generic Type from Field getGenericTypeOfCollectionField(Field field)

Description

get Generic Type Of Collection Field

License

Open Source License

Declaration

public static Class<?> getGenericTypeOfCollectionField(Field field) 

Method Source Code

//package com.java2s;
/*/* w w w .  ja va2s .  c om*/
 Copyright 2014 Red Hat, Inc. and/or its affiliates.
    
 This file is part of darcy-ui.
    
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
    
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
    
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.lang.reflect.Field;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class Main {
    public static Class<?> getGenericTypeOfCollectionField(Field field) {
        Type genericType = field.getGenericType();

        if (!(genericType instanceof ParameterizedType)) {
            throw new IllegalArgumentException("Field is not a ParameterizedType.");
        }

        Type[] genericTypes = ((ParameterizedType) genericType).getActualTypeArguments();

        if (genericTypes.length != 1) {
            throw new IllegalArgumentException("Field does not have a single generic type.");
        }

        if (!(genericTypes[0] instanceof Class)) {
            throw new IllegalArgumentException("Field's generic type is not a class?");
        }

        return (Class<?>) genericTypes[0];
    }
}

Related

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