org.springframework.boot.devtools.autoconfigure.HateoasObjenesisCacheDisabler.java Source code

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Here is the source code for org.springframework.boot.devtools.autoconfigure.HateoasObjenesisCacheDisabler.java

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/*
 * Copyright 2012-2017 the original author or authors.
 *
 * 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.springframework.boot.devtools.autoconfigure;

import java.lang.reflect.Field;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;

/**
 * Replaces the Objenesis instance in Spring HATEOAS's {@code DummyInvocationUtils} with
 * one that does not perform any caching. The cache is problematic as it's keyed on class
 * name which leads to {@code ClassCastExceptions} as the class loader changes across
 * restarts.
 *
 * @author Andy Wilkinson
 * @since 1.3.0
 */
class HateoasObjenesisCacheDisabler implements InitializingBean {

    private static final Log logger = LogFactory.getLog(HateoasObjenesisCacheDisabler.class);

    private static boolean cacheDisabled;

    @Override
    public void afterPropertiesSet() {
        disableCaching();
    }

    private void disableCaching() {
        if (!cacheDisabled) {
            cacheDisabled = true;
            doDisableCaching();
        }
    }

    private void doDisableCaching() {
        try {
            Class<?> type = ClassUtils.forName("org.springframework.hateoas.core.DummyInvocationUtils",
                    getClass().getClassLoader());
            removeObjenesisCache(type);
        } catch (Exception ex) {
            // Assume that Spring HATEOAS is not on the classpath and continue
        }
    }

    private void removeObjenesisCache(Class<?> dummyInvocationUtils) {
        try {
            Field objenesisField = ReflectionUtils.findField(dummyInvocationUtils, "OBJENESIS");
            if (objenesisField != null) {
                ReflectionUtils.makeAccessible(objenesisField);
                Object objenesis = ReflectionUtils.getField(objenesisField, null);
                Field cacheField = ReflectionUtils.findField(objenesis.getClass(), "cache");
                ReflectionUtils.makeAccessible(cacheField);
                ReflectionUtils.setField(cacheField, objenesis, null);
            }
        } catch (Exception ex) {
            logger.warn("Failed to disable Spring HATEOAS's Objenesis cache. ClassCastExceptions may occur", ex);
        }
    }

}