package org.nustaq.offheap;
import org.nustaq.offheap.bytez.ByteSource;
import org.nustaq.offheap.bytez.bytesource.BytezByteSource;
import java.util.Iterator;
/**
* An offheap map adding mechanics to encode and decode keys and values.
*
* Again remember keys have to be of fixed size and should be as short as possible.
* Performance and memory consumtpion is best if significant digits are at the
* end of a key (e.g. "year_montH_day" instead "day_month_year".
*
* This class can be used for manual implementation of encoding/decoding.
*
* See StringOffHeapMap for an example on how to do efficient wrapping/encoding of keys
*/
public abstract class FSTCodedOffheapMap<K,V> extends FSTBinaryOffheapMap {
public FSTCodedOffheapMap(int keyLen, long sizeMemBytes, int numberOfElems) {
super(keyLen, sizeMemBytes, numberOfElems);
}
public FSTCodedOffheapMap(String mappedFile, int keyLen, long sizeMemBytes, int numberOfElems) throws Exception {
super(mappedFile, keyLen, sizeMemBytes, numberOfElems);
}
// protected abstract K decodeKey(ByteSource key);
public abstract ByteSource encodeKey(K key);
public abstract ByteSource encodeValue(V value);
public abstract V decodeValue(BytezByteSource val);
public V get( K key ) {
if ( key == null )
return null;
ByteSource bkey = encodeKey(key);
BytezByteSource val = getBinary(bkey);
if ( val == null )
return null;
try {
return decodeValue(val);
}catch (Exception ex) {
System.out.println("ERROR in "+(val.getOff()-getHeaderLen())+" "+printBinaryKey(bkey)+" "+index.get(bkey));
throw new RuntimeException(ex);
}
}
public void put( K key, V value ) {
ByteSource bkey = encodeKey(key);
ByteSource decoded = encodeValue(value);
putBinary(bkey, decoded);
}
public void remove( K key ) {
ByteSource bkey = encodeKey(key);
removeBinary(bkey);
}
/**
* Warning: Concurrent Modification (e.g. add remove elements during iteration) is NOT SUPPORTED
* and NOT CHECKED. Collect keys to change inside an iteration and perform changes on the map after iteration is
* finished.
* @return an iterator on the values contained in this map.
*/
public Iterator<V> values() {
final Iterator<ByteSource> iter = binaryValues();
return new Iterator() {
@Override
public boolean hasNext() {
return iter.hasNext();
}
@Override
public V next() {
BytezByteSource next = (BytezByteSource) iter.next();
return decodeValue(next);
}
@Override
public void remove() {
throw new RuntimeException("unimplemented");
}
};
}
}