IMatchExpression (Eclipse Platform API Specification)

All Superinterfaces:

IExpression
```
public interface IMatchExpression<T>
extends IExpression
```
A match expression is a boolean expression matching a candidate of a specific type. An IEvaluationContext is needed in order to evaluate a match and this class provides two ways of doing that. Either a context is created first and then reused in several subsequent calls to isMatch(IEvaluationContext, Object) or, if no repeated calls are expected, the isMatch(Object) method can be used. It will then create a context on each call.

Since:

2.0

Field Summary
- Fields inherited from interface org.eclipse.equinox.p2.metadata.expression.IExpression
  TYPE_ALL, TYPE_AND, TYPE_ARRAY, TYPE_ASSIGNMENT, TYPE_AT, TYPE_COLLECT, TYPE_CONDITION, TYPE_EQUALS, TYPE_EXISTS, TYPE_FIRST, TYPE_FLATTEN, TYPE_FUNCTION, TYPE_GREATER, TYPE_GREATER_EQUAL, TYPE_INTERSECT, TYPE_LAMBDA, TYPE_LATEST, TYPE_LESS, TYPE_LESS_EQUAL, TYPE_LIMIT, TYPE_LITERAL, TYPE_MATCHES, TYPE_MEMBER, TYPE_NOT, TYPE_NOT_EQUALS, TYPE_OR, TYPE_PARAMETER, TYPE_PIPE, TYPE_SELECT, TYPE_TRAVERSE, TYPE_UNION, TYPE_UNIQUE, TYPE_VARIABLE

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`IEvaluationContext`	`createContext()`	Creates a new context to be passed to repeated subsequent evaluations.
`Object[]`	`getParameters()`	Returns the parameters that this match expression was created with.
`boolean`	`isMatch(IEvaluationContext context, T candidate)`	This method assigns `candidate` to the 'this' variable of the `context` and then evaluates the expression.
`boolean`	`isMatch(T candidate)`	This method creates a new evaluation context and assigns the `candidate` to the 'this' variable of the `context` and then evaluates the expression.

Methods inherited from interface org.eclipse.equinox.p2.metadata.expression.IExpression
accept, evaluate, getExpressionType, toLDAPString, toString

- Method Detail
  - createContext
```
IEvaluationContext createContext()
```
    Creates a new context to be passed to repeated subsequent evaluations. The context will introduce 'this' as an uninitialized variable and make the parameters available.
    
    Returns:
    
    A new evaluation context.
  - getParameters
```
Object[] getParameters()
```
    Returns the parameters that this match expression was created with.
    
    Returns:
    
    An array of parameters, possibly empty but never null.
  - isMatch
```
boolean isMatch(T candidate)
```
    This method creates a new evaluation context and assigns the candidate to the 'this' variable of the context and then evaluates the expression. This is essentially a short form for
    isMatch(createContext(), candidate)
    .
    Parameters:
    
    candidate - The object to test.
    
    Returns:
    
    the result of the evaluation.
  - isMatch
```
boolean isMatch(IEvaluationContext context,
                T candidate)
```
    This method assigns candidate to the 'this' variable of the context and then evaluates the expression.
    
    Parameters:
    
    context - A context
    
    candidate - The object to test.
    
    Returns:
    
    the result of the evaluation.