org.eclipse.core.expressions
Class Expression

java.lang.Object
  org.eclipse.core.expressions.Expression

Direct Known Subclasses:

ActiveShellExpression, LegacyHandlerSubmissionExpression

public abstract class Expression

extends Object

Abstract base class for all expressions provided by the common expression language.

An expression is evaluated by calling evaluate(IEvaluationContext).

This class may be subclassed to provide specific expressions.

Since:

3.0

Field Summary

protected static String	ATT_VALUE Name of the value attribute of an expression (value is value).
static Expression	FALSE The expression corresponding to EvaluationResult.FALSE.
static Expression	TRUE The expression corresponding to EvaluationResult.TRUE.

Constructor Summary

Expression()

Method Summary

void	collectExpressionInfo(ExpressionInfo info) Collects information about this expression tree.
ExpressionInfo	computeExpressionInfo() Computes the expression information for the given expression tree.
abstract EvaluationResult	evaluate(IEvaluationContext context) Evaluates this expression.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ATT_VALUE

protected static final String ATT_VALUE

Name of the value attribute of an expression (value is value).

See Also:

Constant Field Values

TRUE

public static final Expression TRUE

The expression corresponding to EvaluationResult.TRUE.

FALSE

public static final Expression FALSE

The expression corresponding to EvaluationResult.FALSE.

Constructor Detail

Expression

public Expression()

Method Detail

evaluate

public abstract EvaluationResult evaluate(IEvaluationContext context)
                                   throws CoreException

Evaluates this expression.

Parameters:

context - an evaluation context providing information like variable, name spaces, etc. necessary to evaluate this expression

Returns:

the result of the expression evaluation

Throws:

CoreException - if the evaluation failed. The concrete reason is defined by the subclass implementing this method

computeExpressionInfo

public final ExpressionInfo computeExpressionInfo()

Computes the expression information for the given expression tree.

This is a convenience method for collecting the expression information using collectExpressionInfo(ExpressionInfo).

Returns:

the expression information

Since:

3.2

collectExpressionInfo

public void collectExpressionInfo(ExpressionInfo info)

Collects information about this expression tree. This default implementation add the expression's type to the set of misbehaving expression types.

Parameters:

info - the expression information object used to collect the information

Since:

3.2