/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
*
* http://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.apache.sshd.common.util;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.sshd.common.Closeable;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.future.CloseFuture;
import org.apache.sshd.common.future.DefaultCloseFuture;
import org.apache.sshd.common.future.DefaultSshFuture;
import org.apache.sshd.common.future.SshFuture;
import org.apache.sshd.common.future.SshFutureListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility class to help with {@link Closeable}s.
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class CloseableUtils {
public static CloseFuture closed() {
CloseFuture future = new DefaultCloseFuture(null);
future.setClosed();
return future;
}
public static Closeable parallel(final Collection<? extends Closeable> closeables) {
return parallel(null, closeables);
}
public static Closeable parallel(final Object lock, final Collection<? extends Closeable> closeables) {
return parallel(lock, closeables.toArray(new Closeable[closeables.size()]));
}
public static Closeable parallel(final Closeable... closeables) {
return parallel(null, closeables);
}
public static Closeable parallel(final Object lock, final Closeable... closeables) {
int nbNonNulls = 0;
for (Closeable closeable : closeables) {
if (closeable != null) {
nbNonNulls++;
}
}
if (nbNonNulls == 0) {
return new Closeable() {
final CloseFuture future = new DefaultCloseFuture(lock);
public boolean isClosed() {
return future.isClosed();
}
public boolean isClosing() {
return isClosed();
}
public CloseFuture close(boolean immediately) {
future.setClosed();
return future;
}
};
} else if (nbNonNulls == 1) {
for (Closeable closeable : closeables) {
if (closeable != null) {
return closeable;
}
}
throw new IllegalStateException();
} else {
return new Closeable() {
final CloseFuture future = new DefaultCloseFuture(lock);
final AtomicBoolean closing = new AtomicBoolean();
public boolean isClosed() {
return future.isClosed();
}
public boolean isClosing() {
return closing.get();
}
public CloseFuture close(boolean immediately) {
final AtomicInteger count = new AtomicInteger(closeables.length);
if (closing.compareAndSet(false, true)) {
SshFutureListener<CloseFuture> listener = new SshFutureListener<CloseFuture>() {
public void operationComplete(CloseFuture f) {
if (count.decrementAndGet() == 0) {
future.setClosed();
}
}
};
for (Closeable c : closeables) {
if (c != null) {
c.close(immediately).addListener(listener);
} else {
listener.operationComplete(null);
}
}
}
return future;
}
};
}
}
public static Closeable sequential(final Collection<? extends Closeable> closeables) {
return sequential(null, closeables);
}
public static Closeable sequential(final Object lock, final Collection<? extends Closeable> closeables) {
return sequential(lock, closeables.toArray(new Closeable[closeables.size()]));
}
public static Closeable sequential(final Closeable... closeables) {
return sequential(null, closeables);
}
public static Closeable sequential(final Object lock, final Closeable... closeables) {
int nbNonNulls = 0;
for (Closeable closeable : closeables) {
if (closeable != null) {
nbNonNulls++;
}
}
if (nbNonNulls == 0) {
return new Closeable() {
final CloseFuture future = new DefaultCloseFuture(lock);
public boolean isClosed() {
return future.isClosed();
}
public boolean isClosing() {
return isClosed();
}
public CloseFuture close(boolean immediately) {
future.setClosed();
return future;
}
};
} else if (nbNonNulls == 1) {
for (Closeable closeable : closeables) {
if (closeable != null) {
return closeable;
}
}
throw new IllegalStateException();
} else {
return new Closeable() {
final DefaultCloseFuture future = new DefaultCloseFuture(lock);
final AtomicBoolean closing = new AtomicBoolean();
public boolean isClosed() {
return future.isClosed();
}
public boolean isClosing() {
return closing.get();
}
public CloseFuture close(final boolean immediately) {
if (closing.compareAndSet(false, true)) {
final Iterator<Closeable> iterator = Arrays.asList(closeables).iterator();
SshFutureListener<CloseFuture> listener = new SshFutureListener<CloseFuture>() {
public void operationComplete(CloseFuture previousFuture) {
while (iterator.hasNext()) {
Closeable c = iterator.next();
if (c != null) {
CloseFuture nextFuture = c.close(immediately);
nextFuture.addListener(this);
return;
}
}
if (!iterator.hasNext()) {
future.setClosed();
}
}
};
listener.operationComplete(null);
}
return future;
}
};
}
}
public static <T extends SshFuture> CloseFuture parallel(final SshFuture<T>... futures) {
return parallel(null, futures);
}
public static <T extends SshFuture> CloseFuture parallel(Object lock, final SshFuture<T>... futures) {
final CloseFuture future = new DefaultCloseFuture(lock);
if (futures.length > 0) {
final AtomicInteger count = new AtomicInteger(futures.length);
SshFutureListener<T> listener = new SshFutureListener<T>() {
public void operationComplete(T f) {
if (count.decrementAndGet() == 0) {
future.setClosed();
}
}
};
for (SshFuture<T> f : futures) {
if (f != null) {
f.addListener(listener);
} else {
listener.operationComplete(null);
}
}
} else {
future.setClosed();
}
return future;
}
public static Builder builder() {
return new Builder();
}
public static Builder builder(Logger logger, Object lock) {
return new Builder();
}
public static class Builder {
private final Object lock;
private Closeable closeable = null;
public Builder() {
this(null);
}
public Builder(Object lock) {
this.lock = lock;
}
public <T extends SshFuture> Builder when(final SshFuture<T>... futures) {
return close(new Closeable() {
private volatile boolean closing;
private volatile boolean closed;
public CloseFuture close(boolean immediately) {
closing = true;
if (immediately) {
for (SshFuture<?> future : futures) {
if (future instanceof DefaultSshFuture) {
((DefaultSshFuture<?>) future).setValue(new SshException("Closed"));
}
}
closed = true;
return closed();
} else {
return CloseableUtils.parallel(lock, futures).addListener(new SshFutureListener<CloseFuture>() {
public void operationComplete(CloseFuture future) {
closed = true;
}
});
}
}
public boolean isClosed() {
return closed;
}
public boolean isClosing() {
return closing || closed;
}
});
}
public <T extends SshFuture> Builder when(Collection<? extends SshFuture<T>> futures) {
return when(futures.toArray(new SshFuture[futures.size()]));
}
public Builder sequential(Closeable... closeables) {
return close(CloseableUtils.sequential(lock, closeables));
}
public Builder sequential(Collection<Closeable> closeables) {
return close(CloseableUtils.sequential(lock, closeables));
}
public Builder parallel(Closeable... closeables) {
return close(CloseableUtils.parallel(lock, closeables));
}
public Builder parallel(Collection<? extends Closeable> closeables) {
return close(CloseableUtils.parallel(lock, closeables));
}
public Builder close(Closeable c) {
if (closeable == null) {
closeable = c;
} else {
closeable = CloseableUtils.sequential(lock, closeable, c);
}
return this;
}
public Closeable build() {
if (closeable == null) {
closeable = new Closeable() {
private volatile boolean closed;
public CloseFuture close(boolean immediately) {
closed = true;
return closed();
}
public boolean isClosed() {
return closed;
}
public boolean isClosing() {
return closed;
}
};
}
return closeable;
}
}
public static abstract class AbstractCloseable implements Closeable {
protected static final int OPENED = 0;
protected static final int GRACEFUL = 1;
protected static final int IMMEDIATE = 2;
protected static final int CLOSED = 3;
/** Our logger */
protected final Logger log = LoggerFactory.getLogger(getClass());
/** Lock object for this session state */
protected final Object lock;
/** State of this object */
protected final AtomicInteger state = new AtomicInteger(OPENED);
/** A future that will be set 'closed' when the object is actually closed */
protected final CloseFuture closeFuture;
protected AbstractCloseable() {
this(new Object());
}
protected AbstractCloseable(Object lock) {
this.lock = lock;
this.closeFuture = new DefaultCloseFuture(lock);
}
public CloseFuture close(boolean immediately) {
if (immediately) {
if (state.compareAndSet(OPENED, IMMEDIATE) || state.compareAndSet(GRACEFUL, IMMEDIATE)) {
log.debug("Closing {} immediately", this);
preClose();
doCloseImmediately();
log.debug("{} closed", this);
} else {
log.debug("{} is already {}", this, state.get() == CLOSED ? "closed" : "closing");
}
} else {
if (state.compareAndSet(OPENED, GRACEFUL)) {
log.debug("Closing {} gracefully", this);
preClose();
SshFuture<CloseFuture> grace = doCloseGracefully();
if (grace != null) {
grace.addListener(new SshFutureListener<CloseFuture>() {
public void operationComplete(CloseFuture future) {
if (state.compareAndSet(GRACEFUL, IMMEDIATE)) {
doCloseImmediately();
log.debug("{} closed", AbstractCloseable.this);
}
}
});
} else {
if (state.compareAndSet(GRACEFUL, IMMEDIATE)) {
doCloseImmediately();
log.debug("{} closed", this);
}
}
} else {
log.debug("{} is already {}", this, state.get() == CLOSED ? "closed" : "closing");
}
}
return closeFuture;
}
public boolean isClosed() {
return state.get() == CLOSED;
}
public boolean isClosing() {
return state.get() != OPENED;
}
protected void preClose() {
}
protected CloseFuture doCloseGracefully() {
return null;
}
protected void doCloseImmediately() {
closeFuture.setClosed();
state.set(CLOSED);
}
protected Builder builder() {
return new Builder(lock);
}
}
public static abstract class AbstractInnerCloseable extends AbstractCloseable {
protected abstract Closeable getInnerCloseable();
@Override
protected CloseFuture doCloseGracefully() {
return getInnerCloseable().close(false);
}
@Override
protected void doCloseImmediately() {
getInnerCloseable().close(true).addListener(new SshFutureListener<CloseFuture>() {
public void operationComplete(CloseFuture future) {
AbstractInnerCloseable.super.doCloseImmediately();
}
});
}
}
private CloseableUtils() {
}
}