Package chemaxon.chemterms

Interface ChemTermsContext

All Known Implementing Classes:

AtomContext, MolContext, ReactionContext, SearchContext

@PublicApi
public interface ChemTermsContext

Interface of expression evaluation contexts. Provides context functions and evaluation time constants for the evaluator engine. Context functions have to be declared using the ChemTermsContext.ProvidesFunction annotation.

Since:

JChem 2.2, Marvin 5.1

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static @interface	ChemTermsContext.ProvidesFunction	Repeatable annotation used on ChemTermsContext implementations to declare the context functions supported by the callContextFunction(String, List) method.
static @interface	ChemTermsContext.ProvidesFunctionContainer	Container for the repeatable ChemTermsContext.ProvidesFunction annotation.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	VARARG	A possible value for ChemTermsContext.ProvidesFunction.maxParameterCount(), signaling that there is no maximum.

Method Summary

Modifier and Type	Method	Description
default Object	callContextFunction(String name, List<Object> params)	Executes the specified context function with the given parameters.
void	clear()	Clears the context.
default Object	getVariable(String name)	Returns the value of a variable.

Field Details

VARARG

static final int VARARG

A possible value for ChemTermsContext.ProvidesFunction.maxParameterCount(), signaling that there is no maximum.

See Also:

• Constant Field Values

Method Details

getVariable

default Object getVariable(String name)

Returns the value of a variable.

In a Chemical Terms expression, a symbol can be either:

• a constant, provided before compilation,
• a variable, provided by this method during the evaluation.

Unlike context functions, supported variables do not have to be listed in an annotation. The evaluator engine simply assumes all unknown symbols (those which were not specified as constants) to be variables, and calls this method to get their value during the evaluation.

Parameters:

name - the name of the variable

Returns:

the value of the variable, or null if this context does not define the given variable

callContextFunction

default Object callContextFunction(String name,
 List<Object> params)
                            throws ChemTermsException

Executes the specified context function with the given parameters. Implementations override this method to implement the specific context element accessors as specified by ChemTermsContext.ProvidesFunction annotations on the implementation.

Parameters:

name - the context function name (as specified by ChemTermsContext.ProvidesFunction.names())

params - the context function parameters. The size of this list must be between the minimum and maximum allowed.

Returns:

the context element, or null if the given function is not supported

Throws:

ChemTermsException - on error

clear

void clear()

Clears the context.