com.shigengyu.hyperion.cache.WorkflowStateCacheLoader.java Source code

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Here is the source code for com.shigengyu.hyperion.cache.WorkflowStateCacheLoader.java

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/*******************************************************************************
 * Copyright 2013-2014 Gengyu Shi
 *
 * 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 com.shigengyu.hyperion.cache;

import java.lang.reflect.Field;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.google.common.cache.CacheLoader;
import com.shigengyu.common.StringMessage;
import com.shigengyu.hyperion.core.StateOwner;
import com.shigengyu.hyperion.core.WorkflowState;
import com.shigengyu.hyperion.core.WorkflowStateException;
import com.shigengyu.hyperion.dao.WorkflowStateDao;

@Service
public class WorkflowStateCacheLoader extends CacheLoader<Class<? extends WorkflowState>, WorkflowState> {

    private static final StateOwner getStateOwner(Class<? extends WorkflowState> workflowStateClass) {

        // Try get annotation on class
        StateOwner stateOwner = workflowStateClass.getAnnotation(StateOwner.class);

        // Try get annotation on declaring class
        Class<?> declaringClass = workflowStateClass;
        while (stateOwner == null && (declaringClass = declaringClass.getDeclaringClass()) != null) {
            stateOwner = declaringClass.getAnnotation(StateOwner.class);
        }

        // Try get annotation on package
        if (stateOwner == null) {
            stateOwner = workflowStateClass.getPackage().getAnnotation(StateOwner.class);
        }

        return stateOwner;
    }

    @Resource(name = "workflowStateDao")
    private WorkflowStateDao workflowStateDao;

    @Override
    @Transactional
    public WorkflowState load(final Class<? extends WorkflowState> key) {
        WorkflowState workflowState;
        try {
            workflowState = key.newInstance();

            StateOwner stateOwner = getStateOwner(key);
            if (stateOwner != null) {
                Field field = WorkflowState.class.getDeclaredField("stateOwner");
                field.setAccessible(true);
                field.set(workflowState, stateOwner);
            }
        } catch (InstantiationException | IllegalAccessException | IllegalArgumentException | SecurityException e) {
            throw new WorkflowStateException(
                    StringMessage.with("Failed to create workflow state instance of type [{}]", key.getName()), e);
        } catch (NoSuchFieldException e) {
            throw new WorkflowStateException("Failed to get stateOwner field in WorkflowState class", e);
        }

        workflowStateDao.saveOrUpdate(workflowState.toEntity());
        return workflowState;
    }
}