org.xbib.io.ftp.fs.FTPClientPool Maven / Gradle / Ivy
package org.xbib.io.ftp.fs;
import org.xbib.io.ftp.client.FTPClient;
import org.xbib.io.ftp.client.FTPFile;
import org.xbib.io.ftp.client.FTPFileFilter;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.nio.file.OpenOption;
import java.time.ZonedDateTime;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
/**
* A pool of FTP clients, allowing multiple commands to be executed concurrently.
*/
final class FTPClientPool {
private final String hostname;
private final int port;
private final FTPEnvironment env;
private final FileSystemExceptionFactory exceptionFactory;
private final BlockingQueue pool;
FTPClientPool(String hostname, int port, FTPEnvironment env) throws IOException {
this.hostname = hostname;
this.port = port;
this.env = env.clone();
this.exceptionFactory = env.getExceptionFactory();
final int poolSize = env.getClientConnectionCount();
this.pool = new ArrayBlockingQueue<>(poolSize);
try {
for (int i = 0; i < poolSize; i++) {
pool.add(new Client(true));
}
} catch (IOException e) {
// creating the pool failed, disconnect all clients
for (Client client : pool) {
try {
client.disconnect();
} catch (IOException e2) {
e.addSuppressed(e2);
}
}
throw e;
}
}
Client get() throws IOException {
try {
Client client = pool.take();
try {
if (!client.isConnected()) {
client = new Client(true);
}
} catch (final Exception e) {
// could not create a new client; re-add the broken client to the pool to prevent pool starvation
pool.add(client);
throw e;
}
client.increaseRefCount();
return client;
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
InterruptedIOException iioe = new InterruptedIOException(e.getMessage());
iioe.initCause(e);
throw iioe;
}
}
Client getOrCreate() throws IOException {
Client client = pool.poll();
if (client == null) {
// nothing was taken from the pool, so no risk of pool starvation if creating the client fails
return new Client(false);
}
try {
if (!client.isConnected()) {
client = new Client(true);
}
} catch (final Exception e) {
// could not create a new client; re-add the broken client to the pool to prevent pool starvation
pool.add(client);
throw e;
}
client.increaseRefCount();
return client;
}
void keepAlive() throws IOException {
List clients = new ArrayList<>();
pool.drainTo(clients);
IOException exception = null;
for (Client client : clients) {
try {
client.keepAlive();
} catch (IOException e) {
exception = add(exception, e);
} finally {
returnToPool(client);
}
}
if (exception != null) {
throw exception;
}
}
boolean isSecure() {
return env instanceof FTPSEnvironment;
}
void close() throws IOException {
List clients = new ArrayList<>();
pool.drainTo(clients);
IOException exception = null;
for (Client client : clients) {
try {
client.disconnect();
} catch (IOException e) {
exception = add(exception, e);
}
}
if (exception != null) {
throw exception;
}
}
private IOException add(IOException existing, IOException e) {
if (existing == null) {
return e;
}
existing.addSuppressed(e);
return existing;
}
private void returnToPool(Client client) {
assert client.refCount == 0;
pool.add(client);
}
final class Client implements Closeable {
private final FTPClient client;
private final boolean pooled;
private FileType fileType;
private FileStructure fileStructure;
private FileTransferMode fileTransferMode;
private int refCount = 0;
private Client(boolean pooled) throws IOException {
this.client = env.createClient(hostname, port);
this.pooled = pooled;
this.fileType = env.getDefaultFileType();
this.fileStructure = env.getDefaultFileStructure();
this.fileTransferMode = env.getDefaultFileTransferMode();
}
private void increaseRefCount() {
refCount++;
}
private int decreaseRefCount() {
if (refCount > 0) {
refCount--;
}
return refCount;
}
private void keepAlive() throws IOException {
client.sendNoOp();
}
private boolean isConnected() {
if (client.isConnected()) {
try {
keepAlive();
return true;
} catch (IOException e) {
// the keep alive failed - treat as not connected, and actually disconnect quietly
disconnectQuietly();
}
}
return false;
}
private void disconnect() throws IOException {
client.disconnect();
}
private void disconnectQuietly() {
try {
client.disconnect();
} catch (IOException e) {
// ignore
}
}
@Override
public void close() throws IOException {
if (decreaseRefCount() == 0) {
if (pooled) {
returnToPool(this);
} else {
disconnect();
}
}
}
String pwd() throws IOException {
String pwd = client.printWorkingDirectory();
if (pwd == null) {
throw new FTPFileSystemException(client.getReplyCode(), client.getReplyString());
}
return pwd;
}
private void applyTransferOptions(TransferOptions options) throws IOException {
if (options.fileType != null && options.fileType != fileType) {
options.fileType.apply(client);
fileType = options.fileType;
}
if (options.fileStructure != null && options.fileStructure != fileStructure) {
options.fileStructure.apply(client);
fileStructure = options.fileStructure;
}
if (options.fileTransferMode != null && options.fileTransferMode != fileTransferMode) {
options.fileTransferMode.apply(client);
fileTransferMode = options.fileTransferMode;
}
}
InputStream newInputStream(String path, OpenOptions options) throws IOException {
assert options.read;
applyTransferOptions(options);
InputStream in = client.retrieveFileStream(path);
if (in == null) {
throw exceptionFactory.createNewInputStreamException(path, client.getReplyCode(), client.getReplyString());
}
refCount++;
return new FTPInputStream(path, in, options.deleteOnClose);
}
OutputStream newOutputStream(String path, OpenOptions options) throws IOException {
assert options.write;
applyTransferOptions(options);
OutputStream out = options.append ? client.appendFileStream(path) : client.storeFileStream(path);
if (out == null) {
throw exceptionFactory.createNewOutputStreamException(path, client.getReplyCode(), client.getReplyString(), options.options);
}
refCount++;
return new FTPOutputStream(path, out, options.deleteOnClose);
}
private void finalizeStream() throws IOException {
assert refCount > 0;
if (!client.completePendingCommand()) {
throw new FTPFileSystemException(client.getReplyCode(), client.getReplyString());
}
if (decreaseRefCount() == 0) {
if (pooled) {
returnToPool(Client.this);
} else {
disconnect();
}
}
}
void storeFile(String path, InputStream local, TransferOptions options, Collection openOptions) throws IOException {
applyTransferOptions(options);
if (!client.storeFile(path, local)) {
throw exceptionFactory.createNewOutputStreamException(path, client.getReplyCode(), client.getReplyString(), openOptions);
}
}
FTPFile[] listFiles(String path) throws IOException {
return client.listFiles(path);
}
FTPFile[] listFiles(String path, FTPFileFilter filter) throws IOException {
return client.listFiles(path, filter);
}
void throwIfEmpty(String path, FTPFile[] ftpFiles) throws IOException {
if (ftpFiles.length == 0) {
throw exceptionFactory.createGetFileException(path, client.getReplyCode(), client.getReplyString());
}
}
void mkdir(String path) throws IOException {
if (!client.makeDirectory(path)) {
throw exceptionFactory.createCreateDirectoryException(path, client.getReplyCode(), client.getReplyString());
}
}
void delete(String path, boolean isDirectory) throws IOException {
boolean success = isDirectory ? client.removeDirectory(path) : client.deleteFile(path);
if (!success) {
throw exceptionFactory.createDeleteException(path, client.getReplyCode(), client.getReplyString(), isDirectory);
}
}
void rename(String source, String target) throws IOException {
if (!client.rename(source, target)) {
throw exceptionFactory.createMoveException(source, target, client.getReplyCode(), client.getReplyString());
}
}
ZonedDateTime mdtm(String path) throws IOException {
FTPFile file = client.mdtmFile(path);
return file == null ? null : file.getTimestamp();
}
private final class FTPInputStream extends InputStream {
private final String path;
private final InputStream in;
private final boolean deleteOnClose;
private boolean open = true;
private FTPInputStream(String path, InputStream in, boolean deleteOnClose) {
this.path = path;
this.in = in;
this.deleteOnClose = deleteOnClose;
}
@Override
public int read() throws IOException {
return in.read();
}
@Override
public int read(byte[] b) throws IOException {
return in.read(b);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
return in.read(b, off, len);
}
@Override
public long skip(long n) throws IOException {
return in.skip(n);
}
@Override
public int available() throws IOException {
return in.available();
}
@Override
public void close() throws IOException {
if (open) {
in.close();
open = false;
finalizeStream();
if (deleteOnClose) {
delete(path, false);
}
}
}
@Override
public synchronized void mark(int readlimit) {
in.mark(readlimit);
}
@Override
public synchronized void reset() throws IOException {
in.reset();
}
@Override
public boolean markSupported() {
return in.markSupported();
}
}
private final class FTPOutputStream extends OutputStream {
private final String path;
private final OutputStream out;
private final boolean deleteOnClose;
private boolean open = true;
private FTPOutputStream(String path, OutputStream out, boolean deleteOnClose) {
this.path = path;
this.out = out;
this.deleteOnClose = deleteOnClose;
}
@Override
public void write(int b) throws IOException {
out.write(b);
}
@Override
public void write(byte[] b) throws IOException {
out.write(b);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
out.write(b, off, len);
}
@Override
public void flush() throws IOException {
out.flush();
}
@Override
public void close() throws IOException {
if (open) {
out.close();
open = false;
finalizeStream();
if (deleteOnClose) {
delete(path, false);
}
}
}
}
}
}
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