package io.ebean.config.properties;

import java.util.Enumeration;
import java.util.Properties;

Loads and evaluates properties and yml configuration.
/**
 * Loads and evaluates properties and yml configuration.
 */
public class PropertiesLoader {

  private static Properties properties;

  
Provides properties by reading known locations.

Main configuration

Firstly loads from main resources
  - application.properties
  - application.yaml
  - ebean.properties


Then loads from local files
  - application.properties
  - application.yaml
  - ebean.properties


Then loads from environment variable EBEAN_PROPS_FILE
Then loads from system property ebean.props.file
Then loads from load.properties

Test configuration

Once the main configuration is read it will try to read common test configuration.
This will only be successful if the test resources are available (i.e. running tests).

Loads from test resources
  - application-test.properties
  - application-test.yaml
  - test-ebean.properties

/**
   * Provides properties by reading known locations.
   * <p>
   * <h3>Main configuration</h3>
   * <p>
   * <p>Firstly loads from main resources</p>
   * <pre>
   *   - application.properties
   *   - application.yaml
   *   - ebean.properties
   * </pre>
   * <p>
   * <p>Then loads from local files</p>
   * <pre>
   *   - application.properties
   *   - application.yaml
   *   - ebean.properties
   * </pre>
   * <p>
   * <p>Then loads from environment variable <em>EBEAN_PROPS_FILE</em></p>
   * <p>Then loads from system property <em>ebean.props.file</em></p>
   * <p>Then loads from <em>load.properties</em></p>
   * <p>
   * <h3>Test configuration</h3>
   * <p>
   * Once the main configuration is read it will try to read common test configuration.
   * This will only be successful if the test resources are available (i.e. running tests).
   * </p>
   * <p>Loads from test resources</p>
   * <pre>
   *   - application-test.properties
   *   - application-test.yaml
   *   - test-ebean.properties
   * </pre>
   */
  public static synchronized Properties load() {

    if (properties == null) {
      Loader loader = new Loader();
      loader.load();
      properties = loader.eval();
    }

    return properties;
  }

  
Return a copy of the properties with 'eval' run on all the values.
This resolves expressions like ${HOME} etc.
/**
   * Return a copy of the properties with 'eval' run on all the values.
   * This resolves expressions like ${HOME} etc.
   */
  public static Properties eval(Properties properties) {
    Properties evalCopy = new Properties();

    Enumeration<?> names = properties.propertyNames();
    while (names.hasMoreElements()) {
      String name = (String)names.nextElement();
      String value = PropertyEval.eval(properties.getProperty(name));
      evalCopy.setProperty(name, value);
    }
    return evalCopy;
  }
}