Are there any advantages between List<CustomObject> and HashMap <String, Object>

Question

I am trying to implement a solution (in Java 1.6) where i need to store some values (for a set of properties) and thinking in three options considering the following three (Any other idea is of course wellcome!)

Option 1

Create a class (call it Property) that can store different type of objects (String, int, boolean...) and and work with the set of properties as a List<Property>

Something like:

private String type; //Store the type of Object
private String name; //Store the name of the property
private String valueStr; //Store the String value
private int valueInt; //Store the int value
private boolean valueBool; //Store the boolean value

I dont really like the idea of having many properties and using only one of them. (only one of the values will be set per property)

Option 2

Use HashMap<String, Object> and parse the type on each case.

Have the good thing that you can get the Property by name

Option 3

Use HashMap<String, Property> Where the String is the name of the property and you can get the value with the name and no need to parse.

Questions are: Which of one you think is the best one? or if none of them are good i would like to hear other ideas

Also is there any performance difference between the List and the HashMap?

Thanks in advance for the help.

Answer 1

I think better is to have a custom Value class like this:

public class MyValue {
    enum Type {
       INT, STRING, BOOL;
    }
    private Type type; //Store the type of Object in Type Enum
    private Object value; //Store the value in Object

    public void setValue(int val) {
       type = Type.INT;
       value = new Integer(val);
    }
    public void setValue(String val) {
       type = Type.STRING;
       value = val;
    }
    public void setValue(boolean val) {
       type = Type.BOOL;
       value = new Boolean(val);
    }

    public String stringVal() {
        // check type to be STRING first
        return (String) value;
    }
    public int intVal() {
        // check type to be INT first
        return ((Integer) value.intValue());
    }
    public boolean booleanVal() {
        // check type to be BOOL first
        return ((Boolean) value.booleanValue());
    }
}

You will need to convert from Object to specific type based on enum Type in your getters.