org.eclipse.aether.spi.connector.transport.Transporter Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2013 Sonatype, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Sonatype, Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.aether.spi.connector.transport;
import java.io.Closeable;
/**
* A transporter for a remote repository. A transporter is responsible for transferring resources between the remote
* repository and the local system. During its operation, the transporter must provide progress feedback via the
* {@link TransportListener} configured on the underlying task.
*
* If applicable, a transporter should obey connect/request timeouts and other relevant settings from the
* {@link org.eclipse.aether.RepositorySystemSession#getConfigProperties() configuration properties} of the repository
* system session.
*
* Note: Implementations must be thread-safe such that a given transporter instance can safely be used
* for concurrent requests.
*/
public interface Transporter
extends Closeable
{
/**
* Classification for exceptions that denote connectivity or authentication issues and any other kind of error that
* is not mapped to another classification code.
*
* @see #classify(Throwable)
*/
public static final int ERROR_OTHER = 0;
/**
* Classification for exceptions that denote a requested resource does not exist in the remote repository. Note that
* cases where a remote repository is completely inaccessible should be classified as {@link #ERROR_OTHER}.
*
* @see #classify(Throwable)
*/
public static final int ERROR_NOT_FOUND = 1;
/**
* Classifies the type of exception that has been thrown from a previous request to the transporter. The exception
* types employed by a transporter are generally unknown to its caller. Where a caller needs to distinguish between
* certain error cases, it employs this method to detect which error case corresponds to the exception.
*
* @param error The exception to classify, must not be {@code null}.
* @return The classification of the error, either {@link #ERROR_NOT_FOUND} or {@link #ERROR_OTHER}.
*/
int classify( Throwable error );
/**
* Checks the existence of a resource in the repository. If the remote repository can be contacted successfully but
* indicates the resource specified in the request does not exist, an exception is thrown such that invoking
* {@link #classify(Throwable)} with that exception yields {@link #ERROR_NOT_FOUND}.
*
* @param task The existence check to perform, must not be {@code null}.
* @throws Exception If the existence of the specified resource could not be confirmed.
*/
void peek( PeekTask task )
throws Exception;
/**
* Downloads a resource from the repository. If the resource is downloaded to a file as given by
* {@link GetTask#getDataFile()} and the operation fails midway, the transporter should not delete the partial file
* but leave its management to the caller.
*
* @param task The download to perform, must not be {@code null}.
* @throws Exception If the transfer failed.
*/
void get( GetTask task )
throws Exception;
/**
* Uploads a resource to the repository.
*
* @param task The upload to perform, must not be {@code null}.
* @throws Exception If the transfer failed.
*/
void put( PutTask task )
throws Exception;
/**
* Closes this transporter and frees any network resources associated with it. Once closed, a transporter must not
* be used for further transfers, any attempt to do so would yield a {@link IllegalStateException} or similar.
* Closing an already closed transporter is harmless and has no effect.
*/
void close();
}