private DiskElement checkForFreeBlock(int bufferLength) throws IOException {
DiskElement diskElement = findFreeBlock(bufferLength);
if (diskElement == null) {
diskElement = new DiskElement();
diskElement.position = randomAccessFile.length();
diskElement.blockSize = bufferLength;
}
return diskElement;
}
/**
* Marks a block as free.
*
* @param diskElement the DiskElement to move to the free space list
*/
private void freeBlock(final DiskElement diskElement) {
totalSize -= diskElement.payloadSize;
diskElement.payloadSize = 0;
// reset Element meta data
diskElement.key = null;
diskElement.hitcount = 0;
diskElement.expiryTime = 0;
freeSpace.add(diskElement);
}
private void writeElement(Element element, Serializable key) throws IOException {
try {
int bufferLength;
long expirationTime = element.getExpirationTime();
MemoryEfficientByteArrayOutputStream buffer = null;
try {
buffer = serializeEntry(element);
bufferLength = buffer.size();
DiskElement diskElement = checkForFreeBlock(bufferLength);
// Write the record
randomAccessFile.seek(diskElement.position);
randomAccessFile.write(buffer.toByteArray(), 0, bufferLength);
buffer = null;
// Add to index, update stats
diskElement.payloadSize = bufferLength;
diskElement.key = key;
diskElement.expiryTime = expirationTime;
diskElement.hitcount = element.getHitCount();
totalSize += bufferLength;
lastElementSize = bufferLength;
synchronized (diskElements) {
diskElements.put(key, diskElement);
}
} catch (OutOfMemoryError e) {
LOG.error("OutOfMemoryError on serialize: " + key);
}
} catch (Exception e) {
// Catch any exception that occurs during serialization
LOG.error(
name
+ "Cache: Failed to write element to disk '"
+ key
+ "'. Initial cause was "
+ e.getMessage(),
e);
}
}