com.julienviet.pgclient.PgCursor Maven / Gradle / Ivy
/*
* Copyright (C) 2017 Julien Viet
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.julienviet.pgclient;
import io.vertx.codegen.annotations.VertxGen;
import io.vertx.core.AsyncResult;
import io.vertx.core.Handler;
/**
* A cursor that reads progressively the rows from Postgres, it is usefull for reading very large result.
*/
@VertxGen
public interface PgCursor {
/**
* Read rows from the cursor, the result is provided asynchronously to the {@code handler}.
*
* @param count the amount of rows to read
* @param handler the handler for the result
*/
void read(int count, Handler>> handler);
/**
* Returns {@code true} when the cursor has results in progress and the {@link #execute} should be called to retrieve
* them.
*
* @return whether the cursor has more results,
*/
boolean hasMore();
/**
* Release the cursor.
*
* It should be called for prepared queries executed with a fetch size.
*/
default void close() {
close(ar -> {});
}
/**
* Like {@link #close()} but with a {@code completionHandler} called when the cursor has been released.
*/
void close(Handler> completionHandler);
}