org.jboss.vfs.util.LazyInputStream Maven / Gradle / Ivy
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* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.vfs.util;
import static org.jboss.vfs.VFSMessages.MESSAGES;
import java.io.IOException;
import java.io.InputStream;
import org.jboss.vfs.VirtualFile;
/**
* Lazy input stream.
*
* Delaying opening stream from underlying virtual file as long as possible.
* Won't be opened if not used at all.
*
* Synchronization is very simplistic, as it's highly unlikely
* there will be a lot of concurrent requests.
*
* @author Ales Justin
*/
public class LazyInputStream extends InputStream {
private VirtualFile file;
private InputStream stream;
public LazyInputStream(VirtualFile file) {
if (file == null) {
throw MESSAGES.nullArgument("file");
}
this.file = file;
}
/**
* Open stream.
*
* @return file's stream
* @throws IOException for any IO error
*/
protected synchronized InputStream openStream() throws IOException {
if (stream == null) { stream = file.openStream(); }
return stream;
}
@Override
public int read() throws IOException {
return openStream().read();
}
@Override
public int read(byte[] b) throws IOException {
return openStream().read(b);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
return openStream().read(b, off, len);
}
@Override
public long skip(long n) throws IOException {
return openStream().skip(n);
}
@Override
public int available() throws IOException {
return openStream().available();
}
@Override
public synchronized void close() throws IOException {
if (stream == null) { return; }
openStream().close();
stream = null; // reset the stream
}
@Override
public void mark(int readlimit) {
try {
openStream().mark(readlimit);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public void reset() throws IOException {
openStream().reset();
}
@Override
public boolean markSupported() {
try {
return openStream().markSupported();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}