org.jiemamy.utils.reflect.FieldUtil.java Source code

Introduction

Here is the source code for org.jiemamy.utils.reflect.FieldUtil.java

Source

/*
 * Copyright 2007-2012 Jiemamy Project and the Others.
 *
 * This file is part of Jiemamy.
 *
 * 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.
 */
package org.jiemamy.utils.reflect;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.apache.commons.lang.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * {@link Field}???
 * 
 * @version $Id$
 * @author j5ik2o
 */
public final class FieldUtil {

    @SuppressWarnings("unused")
    private static final Logger LOG = LoggerFactory.getLogger(FieldUtil.class);

    /**
     * {@link #getElementTypeOfCollectionFromFieldType(Field)}???
     */
    private static final Method GET_ELEMENT_TYPE_OF_COLLECTION_FROM_FIELD_TYPE_METHOD = getElementTypeFromFieldTypeMethod(
            "Collection");

    /**
     * {@link #getElementTypeOfListFromFieldType(Field)}???
     */
    private static final Method GET_ELEMENT_TYPE_OF_LIST_FROM_FIELD_TYPE_METHOD = getElementTypeFromFieldTypeMethod(
            "List");

    /**
     * {@link #getElementTypeOfSetFromFieldType(Field)}???
     */
    private static final Method GET_ELEMENT_TYPE_OF_SET_FROM_FIELD_TYPE_METHOD = getElementTypeFromFieldTypeMethod(
            "Set");

    /**
     * ?????????
     * 
     * @param field 
     * @return ?????
     * @throws IllegalArgumentException ?{@code null}???
     */
    public static Class<?> getElementTypeOfCollectionFromFieldType(Field field) {
        Validate.notNull(field);
        try {
            return (Class<?>) MethodUtil.invoke(GET_ELEMENT_TYPE_OF_COLLECTION_FROM_FIELD_TYPE_METHOD, null,
                    new Object[] { field });
        } catch (Throwable ignore) {
            //ignore
        }
        return null;
    }

    /**
     * ?????????
     * 
     * @param field 
     * @return ?????
     * @throws IllegalArgumentException ?{@code null}???
     */
    public static Class<?> getElementTypeOfListFromFieldType(Field field) {
        Validate.notNull(field);
        try {
            return (Class<?>) MethodUtil.invoke(GET_ELEMENT_TYPE_OF_LIST_FROM_FIELD_TYPE_METHOD, null,
                    new Object[] { field });
        } catch (Throwable ignore) {
            //ignore
        }
        return null;
    }

    /**
     * ?????????
     * 
     * @param field 
     * @return ?????
     * @throws IllegalArgumentException ?{@code null}???
     */
    public static Class<?> getElementTypeOfSetFromFieldType(Field field) {
        Validate.notNull(field);
        try {
            return (Class<?>) MethodUtil.invoke(GET_ELEMENT_TYPE_OF_SET_FROM_FIELD_TYPE_METHOD, null,
                    new Object[] { field });
        } catch (Throwable ignore) {
            //ignore
        }
        return null;
    }

    /**
     * {@link Field}? {@code T}?????
     * 
     * @param <T> ??
     * @param type ??
     * @param field 
     * @param target 
     * @return 
     * @throws IllegalAccessException ???????
     * @throws IllegalArgumentException ??????????
     * @throws IllegalArgumentException ?{@code null}???
     * @see Field#get(Object)
     */
    public static <T> T getValue(Class<T> type, Field field, Object target)
            throws IllegalArgumentException, IllegalAccessException {
        Validate.notNull(type);
        Validate.notNull(field);
        Validate.notNull(target);
        return type.cast(field.get(target));
    }

    /**
     * ??????
     * 
     * @param field 
     * @return ???{@code true}?????????{@code false}
     * @throws IllegalArgumentException ?{@code null}???
     */
    public static boolean isInstanceField(Field field) {
        Validate.notNull(field);
        int mod = field.getModifiers();
        return !Modifier.isStatic(mod) && !Modifier.isFinal(mod);
    }

    /**
     * {@code ReflectionUtil#getElementTypeOf<var>Xxx</var>FromFieldType()}
     * ? {@link Method}??
     * 
     * @param type ???????
     * @return {@code ReflectionUtil#getElementTypeOf<var>Xxx</var>FromFieldType()}?{@link Method}
     * @throws IllegalArgumentException ?{@code null}???
     */
    protected static Method getElementTypeFromFieldTypeMethod(String type) {
        Validate.notNull(type);
        try {
            return ReflectionUtil.class.getMethod("getElementTypeOf" + type + "FromFieldType",
                    new Class[] { Field.class });
        } catch (Throwable ignore) {
            //ignore
        }
        return null;
    }

    private FieldUtil() {
    }

}