Configuration interfaces
At the heart of Saxon is the object net.sf.saxon.Configuration. This contains all the current
settings of configuration options. All Saxon tasks, such as compiling and running queries and transformations, or building and validating source
documents, happen under the control of a Configuration. Many resources are owned by the Configuration, meaning that related
tasks must run under the same Configuration. Most notably, the Configuration holds a NamePool, which is a table allocating integer codes to the qualified names that appear in stylesheets, queries,
schemas, and source documents, and during the execution of a stylesheet or query all the resources used (for example, the stylesheet, all its input
documents, and any schemas it uses) must all use the same NamePool to ensure that they all use the same integer codes for the same
qualified names. However, two Saxon tasks that are unrelated can run under different Configuration objects.
There are subclasses of Configuration containing resources associated with the capabilities of the different Saxon editions: specifically,
com.saxonica.config.ProfessionalConfiguration and com.saxonica.config.EnterpriseConfiguration. In many cases the Configuration is
used as a factory class to deliver services associated with the different capability levels, for example the method getOptimizer() returns
the query optimizer appropriate to the loaded Saxon edition.
Many configuration options have direct setter and getter methods on the Configuration object, for example
setAllowExternalFunctions() and isAllowExternalFunctions(). Some other options have setters and getters on objects
reachable from the Configuration, for example defaults for XSLT processing can be controlled using methods such as
getDefaultXsltCompilerInfo().setXsltVersion(), while defaults for XQuery processing can be controlled using methods such as
getDefaultStaticQueryContext().setLanguageVersion().
The most general mechanism for getting and setting configuration properties, however, is provided by the methods
getConfigurationProperty(name) and setConfigurationProperty(name, value). In these methods the name of the configuration
property is always a string in the form of a URI (for example, "http://saxon.sf.net/feature/initialTemplate"), and the strings available
are all defined by constants in the class net.sf.saxon.lib.FeatureKeys (for example,
FeatureKeys.INITIAL_TEMPLATE). The value is of various types depending on the property. In the vast majority of cases, the property can
be supplied as a string, or it has an alternative, equivalent property that can be supplied as a string. For properties that are essentially boolean in
nature the value can be supplied either as one of the Java constants Boolean.TRUE or Boolean.FALSE, or as one of the strings
"true", "1", "yes", "on", or "false", "0", "no", "off". These choices are designed to suit the conventions of different APIs in which the configuration
options are exposed.
In many APIs for controlling Saxon activities, the Configuration object is not exposed directly, but is hidden below some similar object
acting as the root object for that particular API. Many of these objects provide a direct way to set the configuration options. These are discussed in
the following sections.