spring-batch ItemReader 源码
spring-batch ItemReader 代码
文件路径：/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ItemReader.java
/*
* Copyright 2006-2022 the original author or authors.
*
* 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
*
* https://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 org.springframework.batch.item;
import org.springframework.lang.Nullable;
/**
* Strategy interface for providing the data. <br>
*
* Implementations are expected to be stateful and will be called multiple times for each
* batch, with each call to {@link #read()} returning a different value and finally
* returning <code>null</code> when all input data is exhausted.<br>
*
* Implementations need <b>not</b> be thread-safe and clients of a {@link ItemReader} need
* to be aware that this is the case.<br>
*
* A richer interface (e.g. with a look ahead or peek) is not feasible because we need to
* support transactions in an asynchronous batch.
*
* @author Rob Harrop
* @author Dave Syer
* @author Lucas Ward
* @author Mahmoud Ben Hassine
* @author Taeik Lim
* @since 1.0
*/
@FunctionalInterface
public interface ItemReader<T> {
/**
* Reads a piece of input data and advance to the next one. Implementations
* <strong>must</strong> return <code>null</code> at the end of the input data set. In
* a transactional setting, caller might get the same item twice from successive calls
* (or otherwise), if the first call was in a transaction that rolled back.
* @throws ParseException if there is a problem parsing the current record (but the
* next one may still be valid)
* @throws NonTransientResourceException if there is a fatal exception in the
* underlying resource. After throwing this exception implementations should endeavour
* to return null from subsequent calls to read.
* @throws UnexpectedInputException if there is an uncategorised problem with the
* input data. Assume potentially transient, so subsequent calls to read might
* succeed.
* @throws Exception if an there is a non-specific error.
* @return T the item to be processed or {@code null} if the data source is exhausted
*/
@Nullable
T read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException;
}
相关信息
相关文章
spring-batch ExecutionContext 源码
spring-batch ItemCountAware 源码
spring-batch ItemReaderException 源码
spring-batch ItemStreamException 源码
spring-batch ItemStreamReader 源码
spring-batch ItemStreamSupport 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
6、 golang
-
7、 openharmony