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package org.apache.cayenne.access;

import java.util.Collection;

import org.apache.cayenne.map.EntityResolver;

/**
 * Defines methods used to run Cayenne queries.
 * 
 * @author Andrus Adamchik
 */
public interface QueryEngine {

    /**
     * Executes a list of queries wrapping them in its own transaction. Results of
     * execution are passed to {@link OperationObserver}object via its callback methods.
     * 
     * @since 1.1 The signiture has changed from List to Collection.
     */
    public void performQueries(Collection queries, OperationObserver resultConsumer);

    /**
     * Returns a resolver for this query engine that is capable of resolving between
     * classes, entity names, and obj/db entities
     */
    public EntityResolver getEntityResolver();
}
