package net.onrc.onos.core.matchaction;

import net.onrc.onos.core.util.IdBlock;
import net.onrc.onos.core.util.IdBlockAllocator;
import net.onrc.onos.core.util.UnavailableIdException;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Generates a global unique MatchActionIdId.
 */
public class MatchActionIdGeneratorWithIdBlockAllocator
        implements MatchActionIdGenerator {

        private final IdBlockAllocator allocator;
        private IdBlock idBlock;

        /**
          * Creates a FlowId generator instance using specified ID block allocator.
          *
          * @param allocator the ID block allocator to be used
          */
        public MatchActionIdGeneratorWithIdBlockAllocator(IdBlockAllocator allocator) {
            this.allocator = checkNotNull(allocator);
            this.idBlock = allocator.allocateUniqueIdBlock();
        }

        @Override
        public synchronized MatchActionId getNewId() {
            try {
                return new MatchActionId(idBlock.getNextId());
            } catch (UnavailableIdException e) {
                idBlock = allocator.allocateUniqueIdBlock();
                return new MatchActionId(idBlock.getNextId());
            }
        }
}