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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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package org.apache.cayenne;
import java.util.List;
/**
* Represents a result of query execution. It potentially contain a mix of update counts
* and lists of selected values. Provides API somewhat similar to java.util.Iterator or
* java.sql.ResultSet for scanning through the individual results.
* <p>
* An example of iterating through a response:
* </p>
*
* <pre>
* QueryResponse response = context.performGenericQuery(query);
* for (response.reset(); response.next();) {
* if (response.isList()) {
* List list = response.currentList();
* // ...
* }
* else {
* int[] updateCounts = response.currentUpdateCount();
* // ...
* }
* }
* </pre>
*
* <p>
* In case the structure of the result is known, and only a single list or an update count
* is expected, there is a simpler API to access them:
* </p>
*
* <pre>
* QueryResponse response = context.performGenericQuery(query);
* List list = response.firstList();
* int[] count = response.firstUpdateCount();
* </pre>
*
* @since 1.2
*/
public interface QueryResponse {
/**
* Returns a number of results in the response.
*/
int size();
/**
* Returns whether current iteration result is a list or an update count.
*/
boolean isList();
/**
* Returns a List under the current iterator position. Use {@link #isList()} to check
* the result type before calling this method.
*/
List<?> currentList();
/**
* Returns an update count under the current iterator position. Returned value is an
* int[] to accommodate batch queries. For a regular update result, the value will be
* an int[1]. Use {@link #isList()} to check the result type before calling this
* method.
*/
int[] currentUpdateCount();
/**
* Rewinds response iterator to the next result, returning true if it is available.
*/
boolean next();
/**
* Restarts response iterator.
*/
void reset();
/**
* A utility method for quickly retrieving the first list in the response. Returns
* null if the query has no lists. Note that this method resets current iterator to an
* undefined state.
*/
@SuppressWarnings("rawtypes")
List firstList();
/**
* A utility method for quickly retrieving the first update count from the response.
* Note that this method resets current iterator to an undefined state.
*/
int[] firstUpdateCount();
}