Java Reflection Generic Type from Field getGenericTypes(Field field)

Description

Get the generic types for the given field

License

Apache License

Parameter

Parameter	Description
field	a parameter

Declaration

public static List<Class<?>> getGenericTypes(Field field) 

Method Source Code

//package com.java2s;
/******************************************************************************
 *  Copyright 2015 by OLTPBenchmark Project                                   *
 *                                                                            *
 *  Licensed 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.Field;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;

import java.util.List;

public class Main {
    /**/*from   w  w  w .ja  v a 2 s  .c  o m*/
     * Get the generic types for the given field
     * @param field
     * @return
     */
    public static List<Class<?>> getGenericTypes(Field field) {
        ArrayList<Class<?>> generic_classes = new ArrayList<Class<?>>();
        Type gtype = field.getGenericType();
        if (gtype instanceof ParameterizedType) {
            ParameterizedType ptype = (ParameterizedType) gtype;
            getGenericTypesImpl(ptype, generic_classes);
        }
        return (generic_classes);
    }

    private static void getGenericTypesImpl(ParameterizedType ptype, List<Class<?>> classes) {
        // list the actual type arguments
        for (Type t : ptype.getActualTypeArguments()) {
            if (t instanceof Class) {
                //                System.err.println("C: " + t);
                classes.add((Class<?>) t);
            } else if (t instanceof ParameterizedType) {
                ParameterizedType next = (ParameterizedType) t;
                //                System.err.println("PT: " + next);
                classes.add((Class<?>) next.getRawType());
                getGenericTypesImpl(next, classes);
            }
        } // FOR
        return;
    }
}

Related

1. getGenericTypeOfCollectionField(Field field)
2. getGenericTypes(Field field)
3. getGenericTypes(Field field)
4. getGenericTypes(Field field)
5. getGenericTypes(Field field)