com.google.mr4c.config.category.CategoryBuilder.java Source code

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Here is the source code for com.google.mr4c.config.category.CategoryBuilder.java

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/**
  * Copyright 2014 Google 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.google.mr4c.config.category;

import com.google.mr4c.content.ContentFactories;
import com.google.mr4c.util.MR4CLogging;

import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Properties;

import org.apache.commons.lang3.StringUtils;

import org.slf4j.Logger;

/**
  * Builds up a set of properties for category as directed from various sources
*/
public class CategoryBuilder {

    protected static final Logger s_log = MR4CLogging.getLogger(CategoryBuilder.class);

    private CategoryInfo m_category;
    private Properties m_props = new Properties();

    public CategoryBuilder(CategoryInfo category) {
        m_category = category;
    }

    public Properties getProperties() {
        return m_props;
    }

    /**
      * Implement standard category precedence, in descending order:
      * <ol>
      * <li>External properties</li>
      * <li>Command line arguments</li>
      * <li>System properties</li>
      * <li>Command line argument for list of property files</li>
      * <li>System property for list of property files</li>
      * <li>Environment variable for list of property files</li>
      * <li>Deprecated system properties</li>
      * </ol>
    */
    public void buildStandardCategory(String argsFileList, Properties argsProps, CategorySystemData sysData)
            throws IOException {
        addProperties(sysData.getPropertiesFromDeprecatedNames());
        addPropertiesFromEnvironmentVariableFileList();
        addPropertiesFromSystemPropertyFileList();
        addPropertiesFromCommandLineArgumentFileList(argsFileList);
        addProperties(sysData.getPropertiesFromSystemProperties());
        addProperties(argsProps);
        addProperties(sysData.getPropertiesFromExternalNames());
    }

    public void addProperties(Properties props) {
        m_props.putAll(props);
    }

    public void addPropertiesFromCommandLineArgumentFileList(String fileList) throws IOException {
        addPropertiesFromFileList("command line argument " + m_category.getArgsPrefix(), fileList);
    }

    public void addPropertiesFromSystemPropertyFileList() throws IOException {
        String propName = m_category.getCategoryProperty();
        if (StringUtils.isEmpty(propName)) {
            return;
        }
        String files = System.getProperty(propName);
        addPropertiesFromFileList("system property " + propName, files);
    }

    public void addPropertiesFromEnvironmentVariableFileList() throws IOException {
        String varName = m_category.getEnvironmentVariable();
        if (StringUtils.isEmpty(varName)) {
            return;
        }
        String files = System.getenv(varName);
        addPropertiesFromFileList("environment variable " + varName, files);
    }

    /**
      * Comma delimited files in order of precedence
    */
    public void addPropertiesFromFileList(String source, String propFiles) throws IOException {
        if (StringUtils.isEmpty(propFiles)) {
            return;
        }
        s_log.info("Trying to load {} config properties from files specified by {}: [{}]",
                m_category.getCategoryName(), source, propFiles);

        List<URI> uris = new ArrayList<URI>();
        for (String file : StringUtils.split(propFiles, ",")) {
            file = file.trim();
            uris.add(URI.create(file));
        }
        addProperties(uris);
    }

    /**
      * Files in order of precedence
    */
    public void addProperties(List<URI> propFiles) throws IOException {
        propFiles = new ArrayList<URI>(propFiles);
        Collections.reverse(propFiles); // need to apply in reverse order of precedence
        for (URI file : propFiles) {
            addProperties(file);
        }
    }

    public void addProperties(URI propFile) throws IOException {
        Properties props = ContentFactories.readContentAsProperties(propFile);
        addProperties(props);
    }

}