com.dianping.lion.service.impl.DefaultConfigValueResolver.java Source code

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Here is the source code for com.dianping.lion.service.impl.DefaultConfigValueResolver.java

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/**
 * Project: com.dianping.lion.lion-service-0.0.1
 * 
 * File Created at 2012-9-22
 * $Id$
 * 
 * Copyright 2010 dianping.com.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information of
 * Dianping Company. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with dianping.com.
 */
package com.dianping.lion.service.impl;

import java.util.regex.Matcher;

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

import com.dianping.lion.ServiceConstants;
import com.dianping.lion.entity.Config;
import com.dianping.lion.entity.ConfigInstance;
import com.dianping.lion.service.ConfigService;
import com.dianping.lion.service.ConfigValueResolver;

/**
 * @author danson.liu
 *
 */
public class DefaultConfigValueResolver implements ConfigValueResolver {

    private static final Logger logger = LoggerFactory.getLogger(DefaultConfigValueResolver.class);

    private final ConfigService configService;

    public DefaultConfigValueResolver(ConfigService configService) {
        this.configService = configService;
    }

    @Override
    public String resolve(String configval, int envId) {
        if (configval == null) {
            return null;
        }
        if (configval.contains(ServiceConstants.REF_CONFIG_PREFIX)) {
            try {
                Matcher matcher = ServiceConstants.REF_EXPR_PATTERN.matcher(configval);
                boolean referenceFound = false;
                StringBuffer buffer = new StringBuffer(configval.length() * 2);
                while (matcher.find()) {
                    referenceFound = true;
                    String refkey = matcher.group(1);
                    Config refconfig = configService.findConfigByKey(refkey);
                    if (refconfig == null) {
                        logger.warn("Referenced config[" + refkey + "] not found.");
                        return null;
                    }
                    ConfigInstance refinstance = configService.findInstance(refconfig.getId(), envId,
                            ConfigInstance.NO_CONTEXT);
                    if (refinstance == null) {
                        logger.warn("Referenced config[" + refkey + "] with env[" + envId + "] not found.");
                        return null;
                    }
                    String refval = refinstance.getValue();
                    if (refval == null) {
                        logger.warn("Reference null-valued config[" + refkey + "] with env[" + envId + "].");
                        return null;
                    }
                    String refparams = matcher.group(3);
                    if (StringUtils.isNotBlank(refparams)) {
                        String[] paramList = StringUtils.split(refparams, "&");
                        for (String paramstr : paramList) {
                            String[] paramentry = StringUtils.split(paramstr, "=");
                            refval = StringUtils.replace(refval, "${" + paramentry[0] + "}", paramentry[1]);
                        }
                    }
                    matcher.appendReplacement(buffer, Matcher.quoteReplacement(refval));
                }
                if (referenceFound) {
                    matcher.appendTail(buffer);
                    return buffer.toString();
                }
            } catch (RuntimeException e) {
                logger.error("Resolve referenced config expression[" + configval + "] failed.", e);
                throw e;
            }
        }
        return configval;
    }

}