src/main/java/org/eclipse/openK/core/controller/ServicesConfigCache.java

/**
******************************************************************************
* Copyright © 2018 PTA GmbH.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* 
*     http://www.eclipse.org/legal/epl-v10.html
* 
******************************************************************************
*/

package org.eclipse.openK.core.controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.log4j.Logger;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.openK.api.ServiceDistributionCluster;
import org.eclipse.openK.core.exceptions.HttpStatusException;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Set;

public class ServicesConfigCache {
  private static final Logger logger = Logger.getLogger(ServicesConfigCache.class.getName());
    private static ServicesConfigCache instance = new ServicesConfigCache();


  private ServiceDistributionCluster[] cache;

  private ServicesConfigCache(){
  }

  public static ServicesConfigCache getInstance() {
      return instance;
  }


  public void readServerDistribution(String configFileName) throws HttpStatusException {
    try {
      ServiceDistributionCluster[] dcs = readServerDistributionFromText(new String(Files.readAllBytes(Paths.get(configFileName)), Charset.forName("UTF-8")));
      cache = dcs;

    } catch (IOException e) {
      logger.error("Could not read file "+configFileName+"!", e);
      throw new HttpStatusException(HttpStatus.INTERNAL_SERVER_ERROR_500);
    }
  }

  private ServiceDistributionCluster[] readServerDistributionFromText(String jsonText) throws HttpStatusException {
    ServiceDistributionCluster[] dcs;

    try {
      final ObjectMapper mapper = new ObjectMapper();
      dcs = mapper.readValue(jsonText, ServiceDistributionCluster[].class);
    } catch (IOException e) {
      logger.error("Could not parse file!", e);
      throw new HttpStatusException(HttpStatus.INTERNAL_SERVER_ERROR_500);
    }

    ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
    Validator validator = factory.getValidator();

    for (ServiceDistributionCluster item : dcs) {
      Set<ConstraintViolation<ServiceDistributionCluster>> violations
              = validator.validate(item);
        if (!violations.isEmpty()) {
        logger.error("Error in configfile!: ");
        throw new HttpStatusException(HttpStatus.INTERNAL_SERVER_ERROR_500);
      }
    }
    return dcs;
  }

  public ServiceDistributionCluster[] getCache() {
      return cache;
  }
}