枚举常量

在 Database 类中定义了以下枚举值：

类定义

    public class Database implements java.io.Closeable
    {
        public enum TransactionType
        {
            ReadOnly,
            Update,
            ReadWrite,
            Exclusive
        };
         
        public enum TransactionPriority
        {
            Idle,
            Background,
            Foreground,
            AboveNormal,
            Highest
        };
         
        public enum IsolationLevel 
        {
            Default,
            ReadCommitted,
            RepeatableRead,
            Serializable
        };
         
        /* Transaction log types */
        public enum  LogType
        {
            NoLog,
            RedoLog,
            UndoLog
        };
         
        public enum IndexType 
        {
            Hashtable,
            BTree,
            Patricia,
            RTree,
            RTreeOfPoint,
            Trigram
        }
        static final String[] indexTypeName = 
        {"hash", "tree", "patricia", "rtree", "rtree", "trigram"};
         
        public enum EventType 
        {
            OnNew,
            OnFieldUpdate,
            OnDelete,
            OnDeleteAll,
            OnCheckpoint,
            OnUpdate
        }
        static final String[] eventTypeName = 
        {"new", "update", "delete", "delete_all", "checkpoint", "update"};
         
        public enum CommitPolicy 
        {
            /**
            * Wait until all changes are saved on disk. (the default policy)
            */
            SyncFlush,
            /**
            * Do not flush changes to disk.
            */
            Buffered,   /* runtime buffered transactions */
            /**
            * Delay flushing changes to disk until the size of the changes or number of delayed transactions exceeds
            * the specified threshold value.
            */
            Delayed,
            /**
            * Flush changes to disk asynchronously.
            */
            NoSync
        };
         
        public enum TransSchedPolicy
        {
            /**
            * Honest policy: first-in first-out
            */
            Fifo,
            /**
            * Place readers in queue before writers
            */
            ReaderFavor,
            /**
            * Place writers in queue  before readers
            */
            WriterFavor
        };
         
        public enum BackupType 
        {
            Auto, 
            Snapshot, 
            Incremental
        };
         
        ...
    }

定义

• TransactionType：事务类型

• TransactionPriority：事务优先级

• IsolationLevel：隔离级别

• TransSchedPolicy：事务调度策略

• LogType：事务日志类型

• IndexType：索引类型

• EventType：事件类型

• CommitPolicy：持久数据库事务提交策略

• BackupType：增量备份类型