Lab B.4: Add to the function Library

Deprecated

Goals

• Write a function to display values returned in a hashmap
• Execute the function from a JSP page
• View results in the debug log

Prerequisites

• ...

Exercise

List Values Returned in HashMap

Note: It may not be possible to write a good version of this function with the current implementation of Parameters. Values appear to be passed as strings, using Parameters.add(key-string, value-string). The calling class is then required to know the types and get the appropriate a conversion using getDate(), getBoolean(), getInteger(), or getFloat().

1. Simple display (Integers and Strings only)

Map<String,Object> map = Functions.getLoggedInUserInfo();
for (Map.Entry<String, Object> item : map.entrySet()) {
  Functions.debug( item.getKey() + ":" + item.getValue().toString() );
}

2. Display arbitrary objects (requires explode function)

Map<String,Object> map = Functions.getLoggedInUserInfo();
for (Map.Entry<String, Object> item : map.entrySet()) {
  if ((item.getValue() instanceof String)
  ||  (item.getValue() instanceof Integer)) 
  {
     String value = item.getValue().toString();
     Functions.debug(item.getKey() + ":" + value);
  } else {
     Object obj = item.getValue();
     String obj_name = obj.getClass().getName();
     Functions.debug(item.getKey()+":"+obj_name);
     Parameters params = Functions.getParametersInstance();
     params.add("level",1);
     params.add("object", obj);
     Functions.exec("explode", params);
  }
}

Notes:

• Hover over a debug line to display a long output string
• Learn more: requestParams Object

3. Explode function

//Functions.debug("Function: explode");
//Params:
//   "object" => Object to display
//  { "level" } => Optional indent level
//Notes:
// * Indents 2 spaces for each level of depth.
// * Initial indent level defaults to zero

Object obj = requestParams.getObject("object");
int level = requestParams.getInteger("level", 0); //Default level = 1
String indent = "";
for (int i=0; i<level; i++) { 
  indent = indent + "  "; 
}
Functions.debug(indent + "LIST OF FIELDS");
// FOR ALL FIELDS {
/*
  if ((field instanceof String) {
    Functions.debug(indent + obj);
  } else if ((field instanceof Integer) 
         ||  (field instanceof Date) 
         ||  (field instanceof Float)) 
         ||  (field instanceof Boolean)) 
  {
      Functions.debug(indent + obj.toString());
  } else {
    String field_class = field.getClass().getName();
    Functions.debug(indent + field_class + ":");  
    Parameters params = Functions.getParametersInstance();
    params.add("level",level+1);
    params.add("object", field);
    Functions.exec("explode", params);
  }
}
*/

Notes:

• Variables cannot be declared using the reflection classes "Class" or "Method". Methods which return those values can be invoked, however. So we can do what we want to do--we just can't use intermediate variables to do it. (Hence the long line ....)

4. Do foo

class foo implements bar
{
}

Do Y

stuff...

Next

--Lab X.N: To Be Done--