javaspringspring-integrationniointegration-patterns

Spring Integration File Support

In Spring Integration how to prevent two different machines to work in the same file? I know that nio library(javaSE) provides a mechanism to lock File FileLocker but how can I implement it using Spring Integration? A concrete example would be appreciated.

Solution

  • There is indeed a org.springframework.integration.file.locking.NioFileLocker implementation which can be used for the FileReadingMessageSource option like:

    /**
 * Optional. Sets a {@link FileLocker} to be used to guard files against
 * duplicate processing.
 * <p>
 * <b>The supplied FileLocker must be thread safe</b>
 * @param locker a locker
 */
public void setLocker(FileLocker locker) {

    From the XML perspective it is like this:

    <file:inbound-channel-adapter>
    <file:nio-locker/>
</file:inbound-channel-adapter>

    More info is in the Reference Manual.

    Another option to avoid concurrent access and duplication in differen JVMs is like using FileSystemPersistentAcceptOnceFileListFilter with the shared persistent ConcurrentMetadataStore: https://docs.spring.io/spring-integration/docs/5.0.3.RELEASE/reference/html/files.html#file-reading