/**
* implementation for map.put(Key,Value)
*
* @param keyBytes
* @param value
* @param hash2 a hash code relating to the {@keyBytes} ( not the natural hash of {@keyBytes} )
* @param replaceIfPresent
* @return
*/
V put(final DirectBytes keyBytes, final V value, int hash2, boolean replaceIfPresent) {
lock();
try {
hash2 = hashLookup.startSearch(hash2);
while (true) {
final int pos = hashLookup.nextPos();
if (pos < 0) {
putEntry(keyBytes, value, hash2);
return null;
} else {
final long offset = entriesOffset + pos * entrySize;
tmpBytes.storePositionAndSize(bytes, offset, entrySize);
if (!keyEquals(keyBytes, tmpBytes)) continue;
final long keyLength = keyBytes.remaining();
tmpBytes.skip(keyLength);
if (replaceIfPresent) {
if (putReturnsNull) {
appendInstance(keyBytes, value);
return null;
}
long valuePosition = tmpBytes.position();
tmpBytes.readStopBit();
final long alignPosition = align(tmpBytes.position());
tmpBytes.position(alignPosition);
final V v = readObjectUsing(null, offset + alignPosition);
tmpBytes.position(valuePosition);
appendInstance(keyBytes, value);
return v;
} else {
if (putReturnsNull) {
return null;
}
return readObjectUsing(null, offset + keyLength);
}
}
}
} finally {
unlock();
}
}
/**
* implementation for map.replace(Key,Value) and map.replace(Key,Old,New)
*
* @param keyBytes the key of the entry to be replaced
* @param expectedValue the expected value to replaced
* @param newValue the new value that will only be set if the existing value in the map equals
* the {@param expectedValue} or {@param expectedValue} is null
* @param hash2 a hash code relating to the {@keyBytes} ( not the natural hash of {@keyBytes} )
* @return null if the value was not replaced, else the value that is replaced is returned
*/
V replace(
final DirectBytes keyBytes, final V expectedValue, final V newValue, final int hash2) {
lock();
try {
hashLookup.startSearch(hash2);
while (true) {
final int pos = hashLookup.nextPos();
if (pos < 0) {
return null;
} else {
final long offset = entriesOffset + pos * entrySize;
tmpBytes.storePositionAndSize(bytes, offset, entrySize);
if (!keyEquals(keyBytes, tmpBytes)) continue;
final long keyLength = keyBytes.remaining();
tmpBytes.skip(keyLength);
long valuePosition = tmpBytes.position();
tmpBytes.readStopBit();
final long alignPosition = align(tmpBytes.position());
tmpBytes.position(alignPosition);
final V valueRead = readObjectUsing(null, offset + keyLength);
if (valueRead == null) return null;
if (expectedValue == null || expectedValue.equals(valueRead)) {
tmpBytes.position(valuePosition);
appendInstance(keyBytes, newValue);
}
return valueRead;
}
}
} finally {
unlock();
}
}
/**
* used to acquire and object of type V from the map,
*
* <p>when {@param create }== true, this method is equivalent to :
*
* <pre>
* Object value = map.get("Key");
*
* if ( counter == null ) {
* value = new Object();
* map.put("Key", value);
* }
*
* return value;
* </pre>
*
* @param keyBytes the key of the entry
* @param value an object to be reused, null creates a new object.
* @param hash2 a hash code relating to the {@keyBytes} ( not the natural hash of {@keyBytes} )
* @param create false - if the {@keyBytes} can not be found null will be returned, true - if
* the {@keyBytes} can not be found an value will be acquired
* @return an entry.value whose entry.key equals {@param keyBytes}
*/
V acquire(DirectBytes keyBytes, V value, int hash2, boolean create) {
lock();
try {
hash2 = hashLookup.startSearch(hash2);
while (true) {
int pos = hashLookup.nextPos();
if (pos < 0) {
return create ? acquireEntry(keyBytes, value, hash2) : null;
} else {
final long offset = entriesOffset + pos * entrySize;
tmpBytes.storePositionAndSize(bytes, offset, entrySize);
final boolean miss;
if (LOGGER.isLoggable(Level.FINE)) {
final long start0 = System.nanoTime();
miss = !keyEquals(keyBytes, tmpBytes);
final long time0 = System.nanoTime() - start0;
if (time0 > 1e6) LOGGER.fine("startsWith took " + time0 / 100000 / 10.0 + " ms.");
} else {
miss = !keyEquals(keyBytes, tmpBytes);
}
if (miss) continue;
long valueLengthOffset = keyBytes.remaining() + tmpBytes.position();
tmpBytes.position(valueLengthOffset);
// skip the value length
// todo use the value length to limit reading below
long valueLength = tmpBytes.readStopBit();
final long valueOffset = align(tmpBytes.position()); // includes the stop bit length.
tmpBytes.position(valueOffset);
return readObjectUsing(value, offset + valueOffset);
}
}
} finally {
unlock();
}
}
boolean keyEquals(Bytes keyBytes, MultiStoreBytes tmpBytes) {
// check the length is the same.
long keyLength = tmpBytes.readStopBit();
return keyLength == keyBytes.remaining() && tmpBytes.startsWith(keyBytes);
}
