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package com.qcloud.cos.transfer;
import static com.qcloud.cos.event.SDKProgressPublisher.publishProgress;
import java.util.Collection;
import java.util.LinkedList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import com.qcloud.cos.event.ProgressEventType;
import com.qcloud.cos.event.ProgressListener;
import com.qcloud.cos.event.ProgressListenerChain;
import com.qcloud.cos.event.TransferStateChangeListener;
import com.qcloud.cos.exception.CosClientException;
import com.qcloud.cos.exception.CosServiceException;
/**
* Abstract transfer implementation.
*/
public abstract class AbstractTransfer implements Transfer {
/** The current state of this transfer. */
protected volatile TransferState state = TransferState.Waiting;
protected TransferMonitor monitor;
/** The progress of this transfer. */
private final TransferProgress transferProgress;
private final String description;
/** Hook for adding/removing more progress listeners. */
protected final ProgressListenerChain listenerChain;
/** Collection of listeners to be notified for changes to the state of this transfer via setState() */
protected final Collection stateChangeListeners = new LinkedList();
AbstractTransfer(String description, TransferProgress transferProgress, ProgressListenerChain progressListenerChain) {
this(description, transferProgress, progressListenerChain, null);
}
AbstractTransfer(String description, TransferProgress transferProgress,
ProgressListenerChain progressListenerChain, TransferStateChangeListener stateChangeListener) {
this.description = description;
this.listenerChain = progressListenerChain;
this.transferProgress = transferProgress;
addStateChangeListener(stateChangeListener);
}
/**
* Returns whether or not the transfer is finished (i.e. completed successfully,
* failed, or was canceled). This method should never block.
*
* @return Returns true if this transfer is finished (i.e. completed successfully,
* failed, or was canceled). Returns false if otherwise.
*/
public final synchronized boolean isDone() {
return (state == TransferState.Failed ||
state == TransferState.Completed ||
state == TransferState.Canceled);
}
/**
* Waits for this transfer to complete. This is a blocking call; the current
* thread is suspended until this transfer completes.
*
* @throws CosClientException
* If any errors were encountered in the client while making the
* request or handling the response.
* @throws CosServiceException
* If any errors occurred in Qcloud COS while processing the
* request.
* @throws InterruptedException
* If this thread is interrupted while waiting for the transfer
* to complete.
*/
public void waitForCompletion()
throws CosClientException, CosServiceException, InterruptedException {
try {
Object result = null;
while (!monitor.isDone() || result == null) {
Future f = monitor.getFuture();
result = f.get();
}
} catch (ExecutionException e) {
rethrowExecutionException(e);
}
}
/**
* Waits for this transfer to finish and returns any error that occurred, or
* returns null if no errors occurred.
* This is a blocking call; the current thread
* will be suspended until this transfer either fails or completes
* successfully.
*
* @return Any error that occurred while processing this transfer.
* Otherwise returns null if no errors occurred.
*
* @throws InterruptedException
* If this thread is interrupted while waiting for the transfer
* to complete.
*/
public CosClientException waitForException() throws InterruptedException {
try {
while (!monitor.isDone()) {
monitor.getFuture().get();
}
monitor.getFuture().get();
return null;
} catch (ExecutionException e) {
return unwrapExecutionException(e);
}
}
/**
* Returns a human-readable description of this transfer.
*
* @return A human-readable description of this transfer.
*/
public String getDescription() {
return description;
}
/**
* Returns the current state of this transfer.
*
* @return The current state of this transfer.
*/
public synchronized TransferState getState() {
return state;
}
/**
* Sets the current state of this transfer.
*/
public void setState(TransferState state) {
synchronized (this) {
this.state = state;
}
for ( TransferStateChangeListener listener : stateChangeListeners ) {
listener.transferStateChanged(this, state);
}
}
/**
* Notifies all the registered state change listeners of the state update.
*/
public void notifyStateChangeListeners(TransferState state) {
for ( TransferStateChangeListener listener : stateChangeListeners ) {
listener.transferStateChanged(this, state);
}
}
/**
* Adds the specified progress listener to the list of listeners
* receiving updates about this transfer's progress.
*
* @param listener
* The progress listener to add.
*/
public synchronized void addProgressListener(ProgressListener listener) {
listenerChain.addProgressListener(listener);
}
/**
* Removes the specified progress listener from the list of progress
* listeners receiving updates about this transfer's progress.
*
* @param listener
* The progress listener to remove.
*/
public synchronized void removeProgressListener(ProgressListener listener) {
listenerChain.removeProgressListener(listener);
}
/**
* Adds the given state change listener to the collection of listeners.
*/
public synchronized void addStateChangeListener(TransferStateChangeListener listener) {
if ( listener != null )
stateChangeListeners.add(listener);
}
/**
* Removes the given state change listener from the collection of listeners.
*/
public synchronized void removeStateChangeListener(TransferStateChangeListener listener) {
if ( listener != null )
stateChangeListeners.remove(listener);
}
/**
* Returns progress information about this transfer.
*
* @return The progress information about this transfer.
*/
public TransferProgress getProgress() {
return transferProgress;
}
/**
* Sets the monitor used to poll for transfer completion.
*/
public void setMonitor(TransferMonitor monitor) {
this.monitor = monitor;
}
public TransferMonitor getMonitor() {
return monitor;
}
protected void fireProgressEvent(final ProgressEventType eventType) {
publishProgress(listenerChain, eventType);
}
/**
* Examines the cause of the specified ExecutionException and either
* rethrows it directly (if it's a type of CosClientException) or wraps
* it in an CosClientException and rethrows it.
*
* @param e
* The execution exception to examine.
*/
protected void rethrowExecutionException(ExecutionException e) {
throw unwrapExecutionException(e);
}
/**
* Unwraps the root exception that caused the specified ExecutionException
* and returns it. If it was not an instance of CosClientException, it is
* wrapped as an CosClientException.
*
* @param e
* The ExecutionException to unwrap.
*
* @return The root exception that caused the specified ExecutionException.
*/
protected CosClientException unwrapExecutionException(ExecutionException e) {
Throwable t = e.getCause();
if (t instanceof CosClientException) return (CosClientException)t;
return new CosClientException("Unable to complete transfer: " + t.getMessage(), t);
}
}