code: @JsonProperty("relative_url")
  	public String getRelativeURL() {
  		StringBuilder bld = new StringBuilder();
  		bld.append(this.object);
  		
  		Param[] params = this.getParams();
  		
  		if (params != null && params.length > 0) {
  			bld.append('?');
  			boolean afterFirst = false;
  			
  			for (Param param: params) {
  				if (afterFirst)
  					bld.append('&');
  				else
  					afterFirst = true;
  				
  				if (param instanceof BinaryParam) {
  					//call.addParam(param.name, (InputStream)param.value, ((BinaryParam)param).contentType, "irrelevant");
  					throw new UnsupportedOperationException("Not quite sure what to do with BinaryParam yet");
  				} else {
  					String paramValue = StringUtils.stringifyValue(param, this.mapper);
  					bld.append(StringUtils.urlEncode(param.name));
  					bld.append('=');
  					bld.append(StringUtils.urlEncode(paramValue));
  				}
  			}
  		}
  		
  		return bld.toString();
  	}
docs: What Facebook uses to define the url in a batch