com.sun.mail.pop3.WritableSharedFile Maven / Gradle / Ivy
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package com.sun.mail.pop3;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import javax.mail.util.SharedFileInputStream;
/**
* A subclass of SharedFileInputStream that also allows writing.
*/
class WritableSharedFile extends SharedFileInputStream {
private RandomAccessFile raf;
private AppendStream af;
public WritableSharedFile(File file) throws IOException {
super(file);
try {
raf = new RandomAccessFile(file, "rw");
} catch (IOException ex) {
// if anything goes wrong opening the writable file,
// close the readable file too
super.close();
}
}
/**
* Return the writable version of this file.
*/
public RandomAccessFile getWritableFile() {
return raf;
}
/**
* Close the readable and writable files.
*/
@Override
public void close() throws IOException {
try {
super.close();
} finally {
raf.close();
}
}
/**
* Update the size of the readable file after writing to the file. Updates
* the length to be the current size of the file.
*/
synchronized long updateLength() throws IOException {
datalen = in.length();
af = null;
return datalen;
}
/**
* Return a new AppendStream, but only if one isn't in active use.
*/
public synchronized AppendStream getAppendStream() throws IOException {
if (af != null) {
throw new IOException(
"POP3 file cache only supports single threaded access");
}
af = new AppendStream(this);
return af;
}
}