context base service design, resolve special runtime/environment dependency

context_design.java

	// context interface to resolve env dependency
	public interface ContextService {
  		public Object get(String key);
	}

	// context base
	// alose can impl via aop inspector
	public class BizServiceAdapter implements BizInterface {
		private ContextService context;
		private BizService bizService;

		public BizServiceAdapter(ContextService context, BizService bizService) {
			this.context = context;
			this.bizService = bizService;
		}

		public String echo(String input) {
			if (context.get("appkey") == null)
				throw new NullPointerException("Not Auth");
			return this.bizService.echo(input);
		}
	}

	// origin service
	public class BizService implements BizInterface {
		public String echo(String input) {
			return input;
		}
	}

	public interface BizInterface {
		public String echo(String input);
	}


	//runtime/env based context impl
	
	public class RemotingContextService implements ContextService {
		@Override
		public Object get(String key) {
			// can get from env-var/threadlocal/per-request
			return System.getProperty(key);
		}
	}
	
	public class HttpContextService implements ContextService {
		@Override
		public Object get(String key) {
			return System.getProperty(key);
		}
	}
	
	public class HsfContextService implements ContextService {
		@Override
		public Object get(String key) {
			return System.getProperty(key);
		}
	}