it.could.webdav.DAVOutputStream Maven / Gradle / Ivy
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/* ========================================================================== *
* Copyright (C) 2004-2006, Pier Fumagalli . *
* *
* 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 it.could.webdav;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* A specialized {@link OutputStream} to write to {@link DAVResource}s.
*
* When writing to this {@link OutputStream} the data will be written to
* a temporary file. This temporary file will be moved to its final destination
* (the original file identifying the resource) when the {@link #close()}
* method is called.
*
* This specialized {@link OutputStream} never throws {@link IOException}s,
* but rather relies on the unchecked {@link DAVException} to notify the
* framework of the correct DAV errors.
*
* @author Pier Fumagalli
*/
public class DAVOutputStream extends OutputStream {
/** The original resource {@link File}.
*/
private File temporary = null;
/** The {@link OutputStream} of the temporary {@link File}.
*/
private OutputStream output = null;
/** The {@link DAVResource} associated with this instance.
*/
private DAVResource resource = null;
/**
* Create a new {@link DAVOutputStream} instance.
*/
protected DAVOutputStream(DAVResource resource) {
if (resource == null) throw new NullPointerException();
this.resource = resource;
try {
this.temporary = resource.getParent().getFile();
this.temporary = File.createTempFile(DAVResource.PREFIX,
DAVResource.SUFFIX,
this.temporary);
this.output = new FileOutputStream(this.temporary);
} catch (IOException e) {
String message = "Unable to create temporary file";
throw new DAVException(507, message, e, resource);
}
}
/**
* Rename the temporary {@link File} to the original one.
*/
protected void rename(File temporary, File original)
throws IOException {
if ((original.exists()) && (!original.delete())) {
throw new IOException("Unable to delete original file");
}
if (!temporary.renameTo(original)) {
throw new IOException("Unable to rename temporary file");
}
}
/**
* Abort any data written to the temporary file and delete it.
*/
public void abort() {
if (this.temporary.exists()) this.temporary.delete();
if (this.output != null) try {
this.output.close();
} catch (IOException exception) {
// Swallow the IOException on close
} finally {
this.output = null;
}
}
/**
* Close this {@link OutputStream} {@link #rename(File,File) renaming}
* the temporary file to the {@link DAVResource#getFile() original} one.
*/
public void close() {
if (this.output == null) return;
try {
/* What kind of event should this invocation trigger? */
int event = this.resource.getFile().exists() ?
DAVListener.RESOURCE_MODIFIED:
DAVListener.RESOURCE_CREATED;
/* Make sure that everything is closed and named properly */
this.output.close();
this.output = null;
this.rename(this.temporary, this.resource.getFile());
/* Send notifications to all listeners of the repository */
this.resource.getRepository().notify(this.resource, event);
} catch (IOException e) {
String message = "Error processing temporary file";
throw new DAVException(507, message, e, this.resource);
} finally {
this.abort();
}
}
/**
* Flush any unwritten data to the disk.
*/
public void flush() {
if (this.output == null) throw new IllegalStateException("Closed");
try {
this.output.flush();
} catch (IOException e) {
this.abort();
String message = "Unable to flush buffers";
throw new DAVException(507, message, e, this.resource);
}
}
/**
* Write data to this {@link OutputStream}.
*/
public void write(int b) {
if (this.output == null) throw new IllegalStateException("Closed");
try {
this.output.write(b);
} catch (IOException e) {
this.abort();
String message = "Unable to write data";
throw new DAVException(507, message, e, this.resource);
}
}
/**
* Write data to this {@link OutputStream}.
*/
public void write(byte b[]) {
if (this.output == null) throw new IllegalStateException("Closed");
try {
this.output.write(b);
} catch (IOException e) {
this.abort();
String message = "Unable to write data";
throw new DAVException(507, message, e, this.resource);
}
}
/**
* Write data to this {@link OutputStream}.
*/
public void write(byte b[], int o, int l) {
if (this.output == null) throw new IllegalStateException("Closed");
try {
this.output.write(b, o, l);
} catch (IOException e) {
this.abort();
String message = "Unable to write data";
throw new DAVException(507, message, e, this.resource);
}
}
/**
* Finalize this {@link DAVOutputStream} instance.
*/
public void finalize() {
this.abort();
}
}