com.netsteadfast.greenstep.util.DynamicHqlUtils.java Source code

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Here is the source code for com.netsteadfast.greenstep.util.DynamicHqlUtils.java

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/* 
 * Copyright 2012-2016 bambooCORE, greenstep of copyright Chen Xin Nien
 * 
 * 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.
 * 
 * -----------------------------------------------------------------------
 * 
 * author:    Chen Xin Nien
 * contact: chen.xin.nien@gmail.com
 * 
 */
package com.netsteadfast.greenstep.util;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;

import com.netsteadfast.greenstep.base.Constants;
import com.netsteadfast.greenstep.base.model.dynamichql.DynamicHql;
import com.netsteadfast.greenstep.base.model.dynamichql.Query;

import freemarker.cache.StringTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.Template;

public class DynamicHqlUtils {
    protected static Logger logger = Logger.getLogger(DynamicHqlUtils.class);
    private final static String TEMPLATE_ID = "dynamic-hql-resource";
    private static Map<String, DynamicHql> resourceDataMap = new HashMap<String, DynamicHql>();

    public static DynamicHql loadResource(String resource) throws Exception {
        DynamicHql dynamicHql = resourceDataMap.get(resource);
        if (dynamicHql == null) {
            InputStream in = null;
            try {
                in = DynamicHqlUtils.class.getResourceAsStream("/dynamichql/" + resource);
                byte[] xmlBytes = IOUtils.toByteArray(in);
                JAXBContext jaxbContext = JAXBContext.newInstance(DynamicHql.class);
                Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
                dynamicHql = (DynamicHql) jaxbUnmarshaller.unmarshal(new ByteArrayInputStream(xmlBytes));
                resourceDataMap.put(resource, dynamicHql);
            } catch (IOException e) {
                logger.error(e.getMessage().toString());
                throw e;
            } finally {
                if (in != null) {
                    IOUtils.closeQuietly(in);
                }
                in = null;
            }
        }
        return dynamicHql;
    }

    public static String process(String resource, String queryName, Map<String, Object> paramMap) throws Exception {
        DynamicHql dynamicHql = loadResource(resource);
        if (null == dynamicHql) {
            logger.error("no dynamic hql resource.");
            throw new Exception("no dynamic hql resource.");
        }
        String hql = "";
        for (int i = 0; i < dynamicHql.getQuery().size() && hql.length() < 1; i++) {
            Query queryObj = dynamicHql.getQuery().get(i);
            if (!queryObj.getName().equals(queryName)) {
                continue;
            }
            StringTemplateLoader templateLoader = new StringTemplateLoader();
            templateLoader.putTemplate(TEMPLATE_ID, queryObj.getContent());
            Configuration cfg = new Configuration(Configuration.VERSION_2_3_21);
            cfg.setTemplateLoader(templateLoader);
            Template template = cfg.getTemplate(TEMPLATE_ID, Constants.BASE_ENCODING);
            Writer out = new StringWriter();
            template.process(paramMap, out);
            hql = out.toString();
        }
        if (StringUtils.isBlank(hql)) {
            logger.warn("hql is blank.");
        }
        return hql;
    }

}