Add Apache MINA SftpEventListener

- republish certain events as `ApplicationEvent`s.

* * Add ApacheMinaFtplet to provide the same functionality with FTP
* Fix typo

* * Polishing javadocs and event toString() methods

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/ApacheMinaSftpEvent.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import org.apache.sshd.server.session.ServerSession;
+
+import org.springframework.integration.file.remote.server.FileServerEvent;
+
+/**
+ * {@code ApplicationEvent} generated from Apache Mina sftp events.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public abstract class ApacheMinaSftpEvent extends FileServerEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	public ApacheMinaSftpEvent(Object source) {
+		super(source);
+	}
+
+	public ApacheMinaSftpEvent(Object source, Throwable cause) {
+		super(source, cause);
+	}
+
+	public ServerSession getSession() {
+		return (ServerSession) source;
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/ApacheMinaSftpEventListener.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import java.io.IOException;
+import java.nio.file.CopyOption;
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.Map;
+
+import org.apache.sshd.server.session.ServerSession;
+import org.apache.sshd.server.subsystem.sftp.FileHandle;
+import org.apache.sshd.server.subsystem.sftp.SftpEventListener;
+
+import org.springframework.beans.factory.BeanNameAware;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationEventPublisherAware;
+import org.springframework.util.Assert;
+
+/**
+ * A listener for SFTP events emitted by an Apache Mina sshd/sftp server.
+ * It emits selected events as Spring Framework {@code ApplicationEvent}s
+ * which are subclasses of {@link ApacheMinaSftpEvent}.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class ApacheMinaSftpEventListener implements SftpEventListener, ApplicationEventPublisherAware, BeanNameAware, InitializingBean {
+
+	private ApplicationEventPublisher applicationEventPublisher;
+
+	private String beanName;
+
+	@Override
+	public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
+		this.applicationEventPublisher = applicationEventPublisher;
+	}
+
+	protected ApplicationEventPublisher getApplicationEventPublisher() {
+		return this.applicationEventPublisher;
+	}
+
+	@Override
+	public void setBeanName(String name) {
+		this.beanName = name;
+	}
+
+	public String getBeanName() {
+		return this.beanName;
+	}
+
+	@Override
+	public void afterPropertiesSet() {
+		Assert.state(this.applicationEventPublisher != null, "An ApplicationEventPublisher is required");
+	}
+
+	@Override
+	public void initialized(ServerSession session, int version) {
+		this.applicationEventPublisher.publishEvent(new SessionOpenedEvent(session, version));
+	}
+
+	@Override
+	public void destroying(ServerSession session) throws IOException {
+		this.applicationEventPublisher.publishEvent(new SessionClosedEvent(session));
+	}
+
+	@Override
+	public void created(ServerSession session, Path path, Map<String, ?> attrs, Throwable thrown) {
+		this.applicationEventPublisher.publishEvent(new DirectoryCreatedEvent(session, path, attrs));
+	}
+
+	@Override
+	public void removed(ServerSession session, Path path, boolean isDirectory, Throwable thrown) {
+		this.applicationEventPublisher.publishEvent(new PathRemovedEvent(session, path, isDirectory, thrown));
+	}
+
+	@Override
+	public void written(ServerSession session, String remoteHandle, FileHandle localHandle, long offset, byte[] data,
+			int dataOffset, int dataLen, Throwable thrown) {
+
+		this.applicationEventPublisher.publishEvent(new FileWrittenEvent(session, remoteHandle, localHandle.getFile(),
+				dataLen, thrown));
+	}
+
+	@Override
+	public void moved(ServerSession session, Path srcPath, Path dstPath, Collection<CopyOption> opts,
+			Throwable thrown) {
+
+		this.applicationEventPublisher.publishEvent(new PathMovedEvent(session, srcPath, dstPath, thrown));
+	}
+
+	@Override
+	public String toString() {
+		return "ApacheMinaSftpEventListener [beanName=" + this.beanName + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/DirectoryCreatedEvent.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import java.nio.file.Path;
+import java.util.Map;
+
+/**
+ * An event emitted when a directory is created.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class DirectoryCreatedEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	private final Path path;
+
+	private final Map<String, ?> attrs;
+
+	public DirectoryCreatedEvent(Object source, Path path, Map<String, ?> attrs) {
+		super(source);
+		this.path = path;
+		this.attrs = attrs;
+	}
+
+	public Path getPath() {
+		return this.path;
+	}
+
+	public Map<String, ?> getAttrs() {
+		return this.attrs;
+	}
+
+	@Override
+	public String toString() {
+		return "DirectoryCreatedEvent [path=" + this.path
+				+ ", attrs=" + this.attrs
+				+ ", clientAddress=" + getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/FileWrittenEvent.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import java.nio.file.Path;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * An event that is emitted when a file is written.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class FileWrittenEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	private final String remoteHandle;
+
+	private final Path file;
+
+	private final int dataLen;
+
+	public FileWrittenEvent(Object source, String remoteHandle, Path file, int dataLen, @Nullable Throwable thrown) {
+		super(source, thrown);
+		this.remoteHandle = remoteHandle;
+		this.file = file;
+		this.dataLen = dataLen;
+	}
+
+	public String getRemoteHandle() {
+		return this.remoteHandle;
+	}
+
+	public Path getFile() {
+		return this.file;
+	}
+
+	public int getDataLen() {
+		return this.dataLen;
+	}
+
+	@Override
+	public String toString() {
+		return "FileWrittenEvent [remoteHandle=" + this.remoteHandle
+				+ ", file=" + this.file
+				+ ", dataLen=" + this.dataLen
+				+ (this.cause == null ? "" : ", cause=" + this.cause)
+				+ ", clientAddress=" + getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/PathMovedEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import java.nio.file.Path;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * An event emitted when a path is moved.
+ * @author Gary Russell
+ *
+ * @since 5.2
+ *
+ */
+public class PathMovedEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	private final Path srcPath;
+
+	private final Path dstPath;
+
+	public PathMovedEvent(Object source, Path srcPath, Path dstPath, @Nullable Throwable thrown) {
+		super(source, thrown);
+		this.srcPath = srcPath;
+		this.dstPath = dstPath;
+	}
+
+	public Path getSrcPath() {
+		return this.srcPath;
+	}
+
+	public Path getDstPath() {
+		return this.dstPath;
+	}
+
+	@Override
+	public String toString() {
+		return "PathMovedEvent [srcPath=" + this.srcPath
+				+ ", dstPath=" + this.dstPath
+				+ (this.cause == null ? "" : ", cause=" + this.cause)
+				+ ", clientAddress=" + getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/PathRemovedEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import java.nio.file.Path;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * An event emitted when a file or directory is removed.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class PathRemovedEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	private final Path path;
+
+	private final boolean isDirectory;
+
+	public PathRemovedEvent(Object source, Path path, boolean isDirectory, @Nullable Throwable thrown) {
+		super(source, thrown);
+		this.path = path;
+		this.isDirectory = isDirectory;
+	}
+
+	public Path getPath() {
+		return this.path;
+	}
+
+	public boolean isDirectory() {
+		return this.isDirectory;
+	}
+
+	@Override
+	public String toString() {
+		return "PathRemovedEvent [path=" + this.path
+				+ ", isDirectory=" + this.isDirectory
+				+ (this.cause == null ? "" : ", cause=" + this.cause)
+				+ ", clientAddress=" + getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/SessionClosedEvent.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import org.apache.sshd.server.session.ServerSession;
+
+/**
+ * An event emitted when a session is closed.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class SessionClosedEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	public SessionClosedEvent(ServerSession session) {
+		super(session);
+	}
+
+	@Override
+	public String toString() {
+		return "SessionClosedEvent [clientAddress=" + getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/SessionOpenedEvent.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2019 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.integration.sftp.server;
+
+import org.apache.sshd.server.session.ServerSession;
+
+/**
+ * An event emitted when a session is opened.
+ *
+ * @author Gary Russell
+ * @since 5.2
+ *
+ */
+public class SessionOpenedEvent extends ApacheMinaSftpEvent {
+
+	private static final long serialVersionUID = 1L;
+
+	private final int clientVersion;
+
+	public SessionOpenedEvent(ServerSession session, int version) {
+		super(session);
+		this.clientVersion = version;
+	}
+
+	public int getClientVersion() {
+		return this.clientVersion;
+	}
+
+	@Override
+	public String toString() {
+		return "SessionOpenedEvent [clientVersion=" + this.clientVersion + ", clientAddress="
+				+ getSession().getClientAddress() + "]";
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/server/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * Provides classes related to SFTP servers.
+ */
+package org.springframework.integration.sftp.server;