com.carrotsearch.console.jcommander.defaultprovider.PropertyFileDefaultProvider Maven / Gradle / Ivy

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/*
 * console-tools
 *
 * Copyright (C) 2019, Carrot Search s.c.
 * All rights reserved.
 */
package com.carrotsearch.console.jcommander.defaultprovider;

import com.carrotsearch.console.jcommander.IDefaultProvider;
import com.carrotsearch.console.jcommander.ParameterException;
import java.io.IOException;
import java.net.URL;
import java.util.Properties;

/**
 * A default provider that reads its default values from a property file.
 *
 * @author cbeust
 */
public class PropertyFileDefaultProvider implements IDefaultProvider {
  public static final String DEFAULT_FILE_NAME = "jcommander.properties";
  private Properties m_properties;

  public PropertyFileDefaultProvider() {
    init(DEFAULT_FILE_NAME);
  }

  public PropertyFileDefaultProvider(String fileName) {
    init(fileName);
  }

  private void init(String fileName) {
    try {
      m_properties = new Properties();
      URL url = ClassLoader.getSystemResource(fileName);
      if (url != null) {
        m_properties.load(url.openStream());
      } else {
        throw new ParameterException(
            "Could not find property file: " + fileName + " on the class path");
      }
    } catch (IOException e) {
      throw new ParameterException("Could not open property file: " + fileName);
    }
  }

  public String getDefaultValueFor(String optionName) {
    int index = 0;
    while (index < optionName.length() && !Character.isLetterOrDigit(optionName.charAt(index))) {
      index++;
    }
    String key = optionName.substring(index);
    return m_properties.getProperty(key);
  }
}