IQuery (Eclipse Platform API Specification)

Type Parameters:

T - The type of input object that this query accepts

All Known Subinterfaces:

IMatchQuery<T>, IQueryWithIndex<T>

All Known Implementing Classes:

ArtifactDescriptorQuery, ArtifactKeyQuery, ExpressionMatchQuery, ExpressionQuery, IUProfilePropertyQuery, MatchQuery, OSGiBundleQuery, UserVisibleRootQuery
```
public interface IQuery<T>
```
The root interface for all queries that can be performed on an IQueryable. A query is a piece of logic that selects some objects from a list of provided inputs using some established criteria.
Any given query must be stable - running the same query on the same inputs must return an equal query result each time the query is executed. Thus a client that has performed a query can freely cache the result as long as they know the query input has not changed.

Since:

2.0

Restriction:

This interface is not intended to be implemented directly by clients.

Restriction:

This interface is not intended to be extended directly by clients.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`IExpression`	`getExpression()`	Returns the IExpression backing this query or `null` if this is not an expression query.
`IQueryResult<T>`	`perform(Iterator<T> iterator)`	Evaluates the query for a specific input.

- Method Detail
  - perform
```
IQueryResult<T> perform(Iterator<T> iterator)
```
    Evaluates the query for a specific input.
    
    Parameters:
    
    iterator - The elements for which to evaluate the query on
    
    Returns:
    
    The results of the query.
  - getExpression
```
IExpression getExpression()
```
    Returns the IExpression backing this query or null if this is not an expression query.
    
    Returns:
    
    An expression or null.