org.skife.jdbi.v2.Query.fold()方法的使用及代码示例

x33g5p2x  于2022-01-28 转载在 其他  
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本文整理了Java中org.skife.jdbi.v2.Query.fold方法的一些代码示例，展示了Query.fold的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Query.fold方法的具体详情如下：
包路径：org.skife.jdbi.v2.Query
类名称：Query
方法名：fold

Query.fold介绍

[英]Used to execute the query and traverse the result set with a accumulator. Folding over the result involves invoking a callback for each row, passing into the callback the return value from the previous function invocation.
[中]用于执行查询并使用累加器遍历结果集。结果上的{$0$}涉及为每一行调用回调，将上一次函数调用的返回值传递到回调中。

代码示例

代码示例来源：origin: apache/hive

  1. /**
  2.  * @param connector                   SQL metadata connector to the metadata storage
  3.  * @param metadataStorageTablesConfig Table config
  4.  *
  5.  * @return all the active data sources in the metadata storage
  6.  */
  7. static Collection<String> getAllDataSourceNames(SQLMetadataConnector connector,
  8.   final MetadataStorageTablesConfig metadataStorageTablesConfig) {
  9.  return connector.getDBI()
  10.    .withHandle((HandleCallback<List<String>>) handle -> handle.createQuery(String.format(
  11.      "SELECT DISTINCT(datasource) FROM %s WHERE used = true",
  12.      metadataStorageTablesConfig.getSegmentsTable()))
  13.      .fold(Lists.<String>newArrayList(),
  14.        (druidDataSources, stringObjectMap, foldController, statementContext) -> {
  15.         druidDataSources.add(MapUtils.getString(stringObjectMap, "datasource"));
  16.         return druidDataSources;
  17.        }));
  18. }

代码示例来源：origin: apache/incubator-druid

  1. .fold(
  2.   new HashMap<>(),
  3.   new Folder3<Map<String, List<Rule>>, Pair<String, List<Rule>>>()

代码示例来源：origin: apache/incubator-druid

  1. ).fold(
  2.   new HashMap<>(),
  3.   new Folder3<Map<String, SupervisorSpec>, Pair<String, SupervisorSpec>>()

代码示例来源：origin: apache/incubator-druid

  1. ).fold(
  2.   new HashMap<>(),
  3.   new Folder3<Map<String, List<VersionedSupervisorSpec>>, Pair<String, VersionedSupervisorSpec>>()

代码示例来源：origin: apache/hive

  1. /**
  2.  * @param connector                   SQL connector to metadata
  3.  * @param metadataStorageTablesConfig Tables configuration
  4.  * @param dataSource                  Name of data source
  5.  *
  6.  * @return List of all data segments part of the given data source
  7.  */
  8. static List<DataSegment> getDataSegmentList(final SQLMetadataConnector connector,
  9.   final MetadataStorageTablesConfig metadataStorageTablesConfig,
  10.   final String dataSource) {
  11.  return connector.retryTransaction((handle, status) -> handle.createQuery(String.format(
  12.    "SELECT payload FROM %s WHERE dataSource = :dataSource",
  13.    metadataStorageTablesConfig.getSegmentsTable()))
  14.    .setFetchSize(getStreamingFetchSize(connector))
  15.    .bind("dataSource", dataSource)
  16.    .map(ByteArrayMapper.FIRST)
  17.    .fold(new ArrayList<>(), (Folder3<List<DataSegment>, byte[]>) (accumulator, payload, control, ctx) -> {
  18.     try {
  19.      final DataSegment segment = DATA_SEGMENT_INTERNER.intern(JSON_MAPPER.readValue(payload, DataSegment.class));
  20.      accumulator.add(segment);
  21.      return accumulator;
  22.     } catch (Exception e) {
  23.      throw new SQLException(e.toString());
  24.     }
  25.    }), 3, DEFAULT_MAX_TRIES);
  26. }

代码示例来源：origin: apache/incubator-druid

  1. @Override
  2. public Collection<String> getAllDataSourceNames()
  3. {
  4.  return connector.getDBI().withHandle(
  5.    handle -> handle.createQuery(
  6.      StringUtils.format("SELECT DISTINCT(datasource) FROM %s", getSegmentsTable())
  7.    )
  8.            .fold(
  9.              new ArrayList<>(),
  10.              new Folder3<List<String>, Map<String, Object>>()
  11.              {
  12.               @Override
  13.               public List<String> fold(
  14.                 List<String> druidDataSources,
  15.                 Map<String, Object> stringObjectMap,
  16.                 FoldController foldController,
  17.                 StatementContext statementContext
  18.               )
  19.               {
  20.                druidDataSources.add(
  21.                  MapUtils.getString(stringObjectMap, "datasource")
  22.                );
  23.                return druidDataSources;
  24.               }
  25.              }
  26.            )
  27.  );
  28. }

代码示例来源：origin: apache/incubator-druid

  1. @Override
  2.  public List<LogType> withHandle(Handle handle)
  3.  {
  4.   return handle
  5.     .createQuery(
  6.       StringUtils.format(
  7.         "SELECT log_payload FROM %1$s WHERE %2$s_id = :entryId",
  8.         logTable, entryTypeName
  9.       )
  10.     )
  11.     .bind("entryId", entryId)
  12.     .map(ByteArrayMapper.FIRST)
  13.     .fold(
  14.       new ArrayList<>(),
  15.       (List<LogType> list, byte[] bytes, FoldController control, StatementContext ctx) -> {
  16.        try {
  17.         list.add(jsonMapper.readValue(bytes, logType));
  18.         return list;
  19.        }
  20.        catch (IOException e) {
  21.         log.makeAlert(e, "Failed to deserialize log")
  22.           .addData("entryId", entryId)
  23.           .addData("payload", StringUtils.fromUtf8(bytes))
  24.           .emit();
  25.         throw new SQLException(e);
  26.        }
  27.       }
  28.     );
  29.  }
  30. }

代码示例来源：origin: apache/incubator-druid

  1. .fold(
  2.   Maps.newLinkedHashMap(),
  3.   new Folder3<Map<Long, LockType>, Pair<Long, LockType>>()

代码示例来源：origin: apache/incubator-druid

  1. .bind("end", interval.getEnd().toString())
  2. .map(ByteArrayMapper.FIRST)
  3. .fold(
  4.   new ArrayList<>(),
  5.   new Folder3<List<DataSegment>, byte[]>()

代码示例来源：origin: com.ning.billing/killbill-osgi-bundles-analytics

  1. public <ContainerType> ContainerType list(Class<ContainerType> containerType)
  2. {
  3.   ContainerBuilder<ContainerType> builder = getContainerMapperRegistry().createBuilderFor(containerType);
  4.   return fold(builder, new Folder3<ContainerBuilder<ContainerType>, ResultType>()
  5.   {
  6.     public ContainerBuilder<ContainerType> fold(ContainerBuilder<ContainerType> accumulator,
  7.                           ResultType rs,
  8.                           FoldController ctl,
  9.                           StatementContext ctx) throws SQLException
  10.     {
  11.       accumulator.add(rs);
  12.       return accumulator;
  13.     }
  14.   }).build();
  15. }

代码示例来源：origin: org.kill-bill.commons/killbill-jdbi

  1. @Override
  2. public <ContainerType> ContainerType list(Class<ContainerType> containerType)
  3. {
  4.   ContainerBuilder<ContainerType> builder = getContainerMapperRegistry().createBuilderFor(containerType);
  5.   return fold(builder, new Folder3<ContainerBuilder<ContainerType>, ResultType>()
  6.   {
  7.     @Override
  8.     public ContainerBuilder<ContainerType> fold(ContainerBuilder<ContainerType> accumulator,
  9.                           ResultType rs,
  10.                           FoldController ctl,
  11.                           StatementContext ctx) throws SQLException
  12.     {
  13.       accumulator.add(rs);
  14.       return accumulator;
  15.     }
  16.   }).build();
  17. }

代码示例来源：origin: com.ning.billing/killbill-osgi-bundles-analytics

  1. public <T> T first(Class<T> containerType)
  2. {
  3.   addStatementCustomizer(StatementCustomizers.MAX_ROW_ONE);
  4.   ContainerBuilder builder = getContainerMapperRegistry().createBuilderFor(containerType);
  5.   return (T) this.fold(builder, new Folder3<ContainerBuilder, ResultType>()
  6.   {
  7.     public ContainerBuilder fold(ContainerBuilder accumulator, ResultType rs, FoldController control, StatementContext ctx) throws SQLException
  8.     {
  9.       accumulator.add(rs);
  10.       control.abort();
  11.       return accumulator;
  12.     }
  13.   }).build();
  14. }

代码示例来源：origin: org.kill-bill.commons/killbill-jdbi

  1. @Override
  2. public <T> T first(Class<T> containerType)
  3. {
  4.   // Kill Bill specific: assume our queries will always either use LIMIT 1 or will return exactly one row (see ResultReturnThing)
  5.   // This saves a roundtrip (set @@SQL_SELECT_LIMIT=1)
  6.   //addStatementCustomizer(StatementCustomizers.MAX_ROW_ONE);
  7.   ContainerBuilder builder = getContainerMapperRegistry().createBuilderFor(containerType);
  8.   return (T) this.fold(builder, new Folder3<ContainerBuilder, ResultType>()
  9.   {
  10.     @Override
  11.     public ContainerBuilder fold(ContainerBuilder accumulator, ResultType rs, FoldController control, StatementContext ctx) throws SQLException
  12.     {
  13.       accumulator.add(rs);
  14.       control.abort();
  15.       return accumulator;
  16.     }
  17.   }).build();
  18. }

代码示例来源：origin: org.jdbi/jdbi

  1. @Test
  2. public void testFluentApi() throws Exception
  3. {
  4.   Map<String, Team> teams = handle.createQuery("select t.name as teamName, " +
  5.                          "       t.mascot as mascot, " +
  6.                          "       p.name as personName, " +
  7.                          "       p.role as role " +
  8.                          "from team t inner join person p on (t.name = p.team)")
  9.                   .map(TeamPersonJoinRow.class)
  10.                   .fold(Maps.<String, Team>newHashMap(), new TeamFolder());
  11.   assertThat(teams, equalTo(expected));
  12. }

代码示例来源：origin: org.kill-bill.commons/killbill-jdbi

  1. @Test
  2. public void testFluentApi() throws Exception
  3. {
  4.   Map<String, Team> teams = handle.createQuery("select t.name as teamName, " +
  5.                          "       t.mascot as mascot, " +
  6.                          "       p.name as personName, " +
  7.                          "       p.role as role " +
  8.                          "from team t inner join person p on (t.name = p.team)")
  9.                   .map(TeamPersonJoinRow.class)
  10.                   .fold(Maps.<String, Team>newHashMap(), new TeamFolder());
  11.   assertThat(teams, equalTo(expected));
  12. }

代码示例来源：origin: org.jdbi/jdbi

  1. @Test
  2. public void testFold() throws Exception
  3. {
  4.   h.prepareBatch("insert into something (id, name) values (:id, :name)")
  5.    .add(1, "Brian")
  6.    .add(2, "Keith")
  7.    .execute();
  8.   Map<String, Integer> rs = h.createQuery("select id, name from something")
  9.                 .fold(new HashMap<String, Integer>(), new Folder2<Map<String, Integer>>()
  10.                 {
  11.                   @Override
  12.                 public Map<String, Integer> fold(Map<String, Integer> a, ResultSet rs, StatementContext context) throws SQLException
  13.                   {
  14.                     a.put(rs.getString("name"), rs.getInt("id"));
  15.                     return a;
  16.                   }
  17.                 });
  18.   assertEquals(2, rs.size());
  19.   assertEquals(Integer.valueOf(1), rs.get("Brian"));
  20.   assertEquals(Integer.valueOf(2), rs.get("Keith"));
  21. }

代码示例来源：origin: org.kill-bill.commons/killbill-jdbi

  1. @Test
  2. public void testFold() throws Exception
  3. {
  4.   h.prepareBatch("insert into something (id, name) values (:id, :name)")
  5.    .add(1, "Brian")
  6.    .add(2, "Keith")
  7.    .execute();
  8.   Map<String, Integer> rs = h.createQuery("select id, name from something")
  9.                 .fold(new HashMap<String, Integer>(), new Folder2<Map<String, Integer>>()
  10.                 {
  11.                   @Override
  12.                 public Map<String, Integer> fold(Map<String, Integer> a, ResultSet rs, StatementContext context) throws SQLException
  13.                   {
  14.                     a.put(rs.getString("name"), rs.getInt("id"));
  15.                     return a;
  16.                   }
  17.                 });
  18.   assertEquals(2, rs.size());
  19.   assertEquals(Integer.valueOf(1), rs.get("Brian"));
  20.   assertEquals(Integer.valueOf(2), rs.get("Keith"));
  21. }

代码示例来源：origin: org.jdbi/jdbi

  1. @Test
  2. public void testFold() throws Exception
  3. {
  4.   DBI dbi = new DBI("jdbc:h2:mem:" + UUID.randomUUID());
  5.   Handle h = dbi.open();
  6.   h.execute("create table something (id int primary key, name varchar(100))");
  7.   h.execute("insert into something (id, name) values (7, 'Mark')");
  8.   h.execute("insert into something (id, name) values (8, 'Tatu')");
  9.   StringBuilder rs = h.createQuery("select name from something order by id")
  10.     .mapTo(String.class)
  11.     .fold(new StringBuilder(), new Folder2<StringBuilder>()
  12.     {
  13.       @Override
  14.       public StringBuilder fold(StringBuilder acc, ResultSet rs, StatementContext ctx) throws SQLException
  15.       {
  16.         acc.append(rs.getString(1)).append(", ");
  17.         return acc;
  18.       }
  19.     });
  20.   rs.delete(rs.length() - 2, rs.length()); // trim the extra ", "
  21.   assertThat(rs.toString(), equalTo("Mark, Tatu"));
  22.   h.close();
  23. }

代码示例来源：origin: org.kill-bill.commons/killbill-jdbi

  1. @Test
  2. public void testFold3() throws Exception
  3. {
  4.   h.prepareBatch("insert into something (id, name) values (:id, :name)")
  5.    .add(1, "Brian")
  6.    .add(2, "Keith")
  7.    .execute();
  8.   List<String> rs = h.createQuery("select name from something order by id")
  9.             .map(StringMapper.FIRST)
  10.             .fold(new ArrayList<String>(), new Folder3<List<String>, String>()
  11.             {
  12.               @Override
  13.             public List<String> fold(List<String> a, String rs, FoldController ctl, StatementContext ctx) throws SQLException
  14.               {
  15.                 a.add(rs);
  16.                 return a;
  17.               }
  18.             });
  19.   assertEquals(2, rs.size());
  20.   assertEquals(Arrays.asList("Brian", "Keith"), rs);
  21. }

代码示例来源：origin: org.jdbi/jdbi

  1. @Test
  2. public void testFold3() throws Exception
  3. {
  4.   h.prepareBatch("insert into something (id, name) values (:id, :name)")
  5.    .add(1, "Brian")
  6.    .add(2, "Keith")
  7.    .execute();
  8.   List<String> rs = h.createQuery("select name from something order by id")
  9.             .mapTo(String.class)
  10.             .fold(new ArrayList<String>(), new Folder3<List<String>, String>()
  11.             {
  12.               @Override
  13.             public List<String> fold(List<String> a, String rs, FoldController ctl, StatementContext ctx) throws SQLException
  14.               {
  15.                 a.add(rs);
  16.                 return a;
  17.               }
  18.             });
  19.   assertEquals(2, rs.size());
  20.   assertEquals(Arrays.asList("Brian", "Keith"), rs);
  21. }

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