Options.java

package org.stokesdrift.config;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Options {

	public enum Key {
		ROOT_PATH(new String[]{ "-r","-root_path" }, null),
		CONFIG_FILE(new String[]{ "-c","-config_file" }, "drift_config.yml"),
		;
		
		private String[] optionAliases;
		private List<String> aliases;
		private String defaultValue;
		
		private Key(String[] options, String defaultValue) {
			this.optionAliases = options;
			this.defaultValue = defaultValue;
		}
		
		public List<String> aliases() {
			if (this.aliases != null) return aliases;			
			return (this.aliases = Arrays.asList(optionAliases));
		}
		
		public boolean supports(String option) {
			return aliases().contains(option);
		}
		
		public String getDefault() {
			return defaultValue;
		}
	}
	
	private Map<Key, String> options = new HashMap<Key,String>();
	
	public Options(String[] args) {
		initializeOptions(args);
	}
	
	public Options(Map<Key, String> options) {
		this.options = options;
	}
	
	/**
	 * Parses out the options based on the arg array
	 * @param args
	 */
	protected void initializeOptions(String[] args) {
	  if (args == null) return;
	  
	  // fallback to env vars
	  if (args.length == 0) {
		 String envOptions = System.getenv().get("STOKES_DRIFT_OPTS");
		 if (envOptions != null) {
			 args = envOptions.split(" ");
		 }
	  }
	  
	  String optionKey = null;
	  for(String arg: args) {
		String key = null;
		String value = null;
		String[] pairs = arg.split("=");
		if (pairs.length == 1) {
			if (optionKey != null) {
				key = optionKey;
				optionKey = null;
				value = pairs[0];
			} else {
				optionKey = pairs[0];
				continue;
			}			
		} else if (pairs.length == 1) {
			key = pairs[0];
			value = pairs[1];
		}
		
		if (key != null && value != null) {
			Key keyEnum = getOptionKeyForOption(key);
			if (keyEnum != null) {
				options.put(keyEnum, value);
			}
		}		
	  }
	}
	
	public String getValue(Key key) {
		String value = options.get(key);
		if (value == null) {
			value = key.defaultValue;
		}
		return value;
	}
	
	public Key getOptionKeyForOption(String option) {
		for (Key key: Key.values()) {
			if (key.supports(option)) return key;
		}
		return null;
	}
	
}