getScanner

获取遍历某个HashKey下所有数据的迭代器，用于局部扫描。

public enum FilterType {
    FT_NO_FILTER(0),
    FT_MATCH_ANYWHERE(1), // match filter string at any position
    FT_MATCH_PREFIX(2),   // match filter string at prefix
    FT_MATCH_POSTFIX(3);  // match filter string at postfix
}
 
 
public class ScanOptions {
    public int timeoutMillis = 5000; // operation timeout in milli-seconds.
                                     // if timeoutMillis > 0, it is a timeout value for current op,
                                     // else the timeout value in the configuration file will be used.
    public int batchSize = 1000; // internal buffer batch size
    public boolean startInclusive = true; // if the startSortKey is included
    public boolean stopInclusive = false; // if the stopSortKey is included
    public FilterType hashKeyFilterType = FilterType.FT_NO_FILTER; // filter type for hash key
    public byte[] hashKeyFilterPattern = null; // filter pattern for hash key
    public FilterType sortKeyFilterType = FilterType.FT_NO_FILTER; // filter type for sort key
    public byte[] sortKeyFilterPattern = null; // filter pattern for sort key
    public boolean noValue = false; // only fetch hash_key and sort_key, but not fetch value
}
 
 
/**
 * Get Scanner for {startSortKey, stopSortKey} within hashKey
 * @param tableName TableHandler name
 * @param hashKey used to decide which partition to put this k-v,
 * @param startSortKey start sort key scan from
 *                     if null or length == 0, means start from begin
 * @param stopSortKey stop sort key scan to
 *                    if null or length == 0, means stop to end
 * @param options scan options like endpoint inclusive/exclusive
 * @return scanner              
 * @throws PException
 */
public PegasusScannerInterface getScanner(String tableName, byte[] hashKey, byte[] startSortKey, byte[] stopSortKey, ScanOptions options) throws PException;

注：

• 参数：需传入TableName、HashKey、StartSortKey、StopSortKey、ScanOptions。
  • StartSortKey和StopSortKey用于指定scan的返回，并通过ScanOptions指定区间的开闭。
  • 如果StartSortKey为null，表示从头开始；如果StopSortKey为null，表示一直读到尾。
  • ScanOptions说明：
    • timeoutMillis：从server端读取数据的超时时间，单位毫秒，默认值为5000。
    • batchSize：从server端读取数据时每批数据的个数，默认值为1000。
    • startInclusive：是否包含StartSortKey，默认为true。
    • stopInclusive：是否包含StopSortKey，默认为false。
    • hashKeyFilterType：HashKey的过滤类型，包括无过滤、任意位置匹配、前缀匹配和后缀匹配，默认无过滤。
    • hashKeyFilterPattern：HashKey的过滤模式串，空串相当于无过滤。
    • sortKeyFilterType：SortKey的过滤类型，包括无过滤、任意位置匹配、前缀匹配和后缀匹配，默认无过滤。
    • sortKeyFilterPattern：SortKey的过滤模式串，空串相当于无过滤。
    • noValue：只返回HashKey和SortKey，不返回Value数据，默认为false。
• 返回值：返回迭代器PegasusScannerInterface。
• 异常：如果出现异常，譬如网络错误、超时错误、服务端错误等，会抛出 PException。