com.vmware.bdd.utils.ScriptForUpdatingEtcHostsGenerator.java Source code

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Here is the source code for com.vmware.bdd.utils.ScriptForUpdatingEtcHostsGenerator.java

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/***************************************************************************
 * Copyright (c) 2014-2015 VMware, Inc. All Rights Reserved.
 * 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.vmware.bdd.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

import com.vmware.bdd.exception.BddException;

public class ScriptForUpdatingEtcHostsGenerator {

    private final static String TEMPLATE_RESOURCE = "/com/vmware/bdd/hostname_generating/script-for-updating-etc-hosts.template";
    private static final Logger logger = Logger.getLogger(ScriptForUpdatingEtcHostsGenerator.class);

    private volatile StringBuilder[] templateContent = new StringBuilder[] { null };
    private FileWriter ScriptForUpdatingEtcHosts;

    public ScriptForUpdatingEtcHostsGenerator() {
        if (ScriptForUpdatingEtcHostsGenerator.class.getResource(TEMPLATE_RESOURCE) == null) {
            throw BddException.SCRIPT_FOR_UPDATING_ETC_HOSTS_TEMPLATE_NOT_FOUND();
        }
    }

    public String generateScriptForUpdatingEtcHosts(String clusterName, String hostsContent) {
        String scriptName = clusterName;
        String scriptPath = Constants.SRCIPT_FOR_UPDATING_ETC_HOSTS_DIR + scriptName;

        File scriptForUpdatingEtcHostsDir = new File(Constants.SRCIPT_FOR_UPDATING_ETC_HOSTS_DIR);
        if (!scriptForUpdatingEtcHostsDir.exists()) {
            try {
                scriptForUpdatingEtcHostsDir.mkdir();
            } catch (BddException e) {
                logger.error("Faid to create script for updating /etc/hosts directory "
                        + Constants.SRCIPT_FOR_UPDATING_ETC_HOSTS_DIR + ".");
                throw BddException.FAILED_TO_GENERATE_SCRIPT_FOR_UPDATING_ETC_HOSTS(e, e.getMessage());
            }
        }

        try {
            File oldScriptForUpdatingEtcHosts = new File(scriptPath);
            if (oldScriptForUpdatingEtcHosts.exists()) {
                oldScriptForUpdatingEtcHosts.delete();
            }

            ScriptForUpdatingEtcHosts = new FileWriter(scriptPath, true);
            ScriptForUpdatingEtcHosts.write(getContentForUpdatingEtcHosts(hostsContent));

            logger.info("Generate script for updating /etc/hosts " + scriptPath + " successfully.");
        } catch (Exception e) {
            logger.error("Faid to generate script for updating /etc/hosts " + scriptPath + ".");
            throw BddException.FAILED_TO_GENERATE_SCRIPT_FOR_UPDATING_ETC_HOSTS(e, e.getMessage());
        } finally {
            if (ScriptForUpdatingEtcHosts != null) {
                try {
                    ScriptForUpdatingEtcHosts.close();
                } catch (IOException e) {
                    throw BddException.FAILED_TO_GENERATE_SCRIPT_FOR_UPDATING_ETC_HOSTS(e, e.getMessage());
                }
            }
        }
        return scriptName;
    }

    public String getContentForUpdatingEtcHosts(String hostsContent) {
        load();

        String scriptContent = new String(getTemplateContent());

        ArrayList<String[]> replacementList = new ArrayList<>();

        replacementList.add(new String[] { "ETC_HOSTS_CONTENT", hostsContent });

        for (String[] replacement : replacementList) {
            scriptContent = StringUtils.replace(scriptContent, replacement[0], replacement[1]);
        }

        return scriptContent;
    }

    private void load() {
        if (isTemplateContentEmpty()) {

            synchronized (templateContent) {
                InputStream templateResStream = ScriptForUpdatingEtcHostsGenerator.class
                        .getResourceAsStream(TEMPLATE_RESOURCE);

                if (templateResStream == null) {
                    throw BddException.SCRIPT_FOR_UPDATING_ETC_HOSTS_TEMPLATE_NOT_FOUND();
                }

                StringBuilder stringBuilder = new StringBuilder();
                try (BufferedReader templateBufReader = new BufferedReader(
                        new InputStreamReader(templateResStream))) {
                    String line = templateBufReader.readLine();
                    while (line != null) {
                        stringBuilder.append(line).append('\n');
                        line = templateBufReader.readLine();
                    }
                } catch (IOException ioe) {
                    throw BddException.SCRIPT_FOR_UPDATING_ETC_HOSTS_TEMPLATE_READ_ERR(ioe, ioe.getMessage());
                }

                setTemplateContent(stringBuilder);
            }
        }
    }

    private boolean isTemplateContentEmpty() {
        return templateContent[0] == null;
    }

    private void setTemplateContent(StringBuilder content) {
        templateContent[0] = content;
    }

    private StringBuilder getTemplateContent() {
        return templateContent[0];
    }

}