Socrates is a Java implementation of a survey engine, that enables you to publish surveys and collect data. This package specifies core ideas, and provides a base implementation of those ideas so as to be able to actually do something useful. You'll need a bit more than this though, but other packages should be available for instance for rendering, for defining surveys, etc.

Socrates is mainly based on XForms, so a full survey consists of four parts:

1. data
2. model
3. layout
4. submission

The data part defines the variables (or: fields) that will hold the collected data. Fields may hold default values.

The model defines properties of the data, like whether a variable must have a value for the data to be valid, or specifying the type of the variable. The following properties may be set:

• relevant
• required
• readonly
• calculate
• constraint
• datatype

All properties except for the datatype can be specified in terms of an (XPath) expression, like:

relevant="true()"
required="foo == 1"

To apply properties to variables, 'binding' is used. This is done through expressions that specify to what variables the properties bind.

The view part of the survey specifies what it 'looks like', although in theory the survey could also be converted to automated speech...

The layout specifies what kind of control is used to obtain data, so for instance a select form element to present a list of values to the user for the question "What is your favourite color?". A control is bound to the variable using the same bind attribute as for properties.

Specifies the way the actual data should be handled.