CassandraにJavaからアクセス

• 必要なjarファイル
• コーディング
  • コーディング例
  • メソッド一覧 [/2010-08-29]

• Cassandra WikiのThriftExamples・API
• akishinさんのJava から Cassandra を使ってみる
• wellflatさんのCassandra Thrift APIのConsistencyLevel

• Hadoop（Map/Reduce）のコーディング例

• describe_cluster_name
• describe_keyspaces
• describe_keyspace
• describe_ring
• describe_version

• get
• get_count [/2010-05-12]
• get_slice
• multiget_slice
• get_range_slices

• insert
• batch_mutate [/2010-08-29]
• remove
• Deletion [/2010-07-03]

String clusterName = client.describe_cluster_name();

Set<String> set = client.describe_keyspaces();

Map<String, Map<String, String>> ksMap =
	client.describe_keyspace("Keyspace1");
Map<String, String> map = ksMap.get("Standard2");

List<TokenRange> list =
	client.describe_ring("Keyspace1");

String ver = client.describe_version();

String key = "jsmith";

ColumnPath colPath = new ColumnPath("Standard2");
colPath.setColumn("age".getBytes(UTF8));

Column col = client.get(
  "Keyspace1", key, colPath, ConsistencyLevel.ONE
).getColumn();

ColumnPath colPath = new ColumnPath("Super1");
colPath.setSuper_column("attr".getBytes(UTF8));
colPath.setColumn("age".getBytes(UTF8));

String key = "jsmith";

ColumnPath colPath = new ColumnPath("Super1");
colPath.setSuper_column("name".getBytes(UTF8));

SuperColumn scol = client.get(
  "Keyspace1", key, colPath, ConsistencyLevel.ONE
).getSuper_column();

//スーパーカラム内の全カラム
List<Column> list = scol.getColumns();

String key = "jsmith";

ColumnParent colParent = new ColumnParent("Standard2");

int count = client.get_count(
  "Keyspace1", key, colParent, ConsistencyLevel.ONE
);

ColumnParent colParent = new ColumnParent("Super1");

int count = client.get_count(
  "Keyspace1", key, colParent, ConsistencyLevel.ONE
);

ColumnParent colParent = new ColumnParent("Super1");
colParent.setSuper_column("name".getBytes(UTF8));

int count = client.get_count(
  "Keyspace1", key, colParent, ConsistencyLevel.ONE
);

String key = "jsmith";

ColumnParent colParent = new ColumnParent("Standard2");

SlicePredicate predicate = new SlicePredicate();
predicate.addToColumn_names("first".getBytes(UTF8));
predicate.addToColumn_names("last" .getBytes(UTF8));
predicate.addToColumn_names("age"  .getBytes(UTF8));

List<ColumnOrSuperColumn> list = client.get_slice(
  "Keyspace1", key, colParent, predicate, ConsistencyLevel.ONE
);

for (ColumnOrSuperColumn cs : list) {
  Column col = cs.getColumn();
  〜
}

SlicePredicate predicate = new SlicePredicate();
predicate.setColumn_names(Arrays.asList(
  "first".getBytes(UTF8),
  "last" .getBytes(UTF8),
  "age"  .getBytes(UTF8)
));

SliceRange range = new SliceRange();
range.setStart ("age" .getBytes(UTF8));
range.setFinish("last".getBytes(UTF8));
range.setCount(3);

SlicePredicate predicate = new SlicePredicate();
predicate.setSlice_range(range);

SliceRange range = new SliceRange();
range.setStart (new byte[0]);
range.setFinish(new byte[0]);
range.setCount(count);

SlicePredicate predicate = new SlicePredicate();
predicate.setSlice_range(range);

String key = "jsmith";

ColumnParent colParent = new ColumnParent("Super1");

SlicePredicate predicate = new SlicePredicate();
predicate.addToColumn_names("name".getBytes(UTF8));
predicate.addToColumn_names("attr".getBytes(UTF8));

List<ColumnOrSuperColumn> list = client.get_slice(
  "Keyspace1", key, colParent, predicate, ConsistencyLevel.ONE
);

for (ColumnOrSuperColumn cs : list) {
  SuperColumn scol = cs.getSuper_column();
  〜
}

String key = "jsmith";

ColumnParent colParent = new ColumnParent("Super1");
colParent.setSuper_column("name".getBytes(UTF8));

SlicePredicate predicate = new SlicePredicate();
predicate.addToColumn_names("first".getBytes(UTF8));
predicate.addToColumn_names("last" .getBytes(UTF8));

List<ColumnOrSuperColumn> list = client.get_slice(
  "Keyspace1", key, colParent, predicate, ConsistencyLevel.ONE
);

for (ColumnOrSuperColumn cs : list) {
  Column col = cs.getColumn();
  〜
}

List<String> keys = new ArrayList<String>();
keys.add("jsmith");
keys.add("hishidama");

ColumnParent colParent = new ColumnParent("Standard2");

SlicePredicate predicate = new SlicePredicate();
predicate.addToColumn_names("first".getBytes(UTF8));
predicate.addToColumn_names("last" .getBytes(UTF8));

Map<String, List<ColumnOrSuperColumn>> map = client.multiget_slice(
  "Keyspace1", keys, colParent, predicate, ConsistencyLevel.ONE
);

for (String key : keys) {
  List<ColumnOrSuperColumn> list = map.get(key);
  for (ColumnOrSuperColumn cs : list) {
    Column col = cs.getColumn();
    〜
  }
}

KeyRange keyRange = new KeyRange();
keyRange.setStart_key("jsmith");
keyRange.setEnd_key  ("jsmith99");
keyRange.setCount(100);

ColumnParent colParent = new ColumnParent("Standard2");

SlicePredicate predicate = new SlicePredicate();
predicate.addToColumn_names("first".getBytes(UTF8));
predicate.addToColumn_names("last" .getBytes(UTF8));

List<KeySlice> list = client.get_range_slices(
  "Keyspace1", colParent, predicate, keyRange, ConsistencyLevel.ONE
);

for (KeySlice slice : list) {
  String key = slice.getKey();
  List<ColumnOrSuperColumn> cols = slice.getColumns();
  for (ColumnOrSuperColumn cs : cols) {
    Column col = cs.getColumn();
    〜
  }
}

String key = "jsmith2";

ColumnPath colPath = new ColumnPath("Standard2");
colPath.setColumn("age".getBytes(UTF8));

byte[] value = "42".getBytes(UTF8);

long timestamp = System.currentTimeMillis() * 1000;

client.insert(
  "Keyspace1", key, colPath, value, timestamp, ConsistencyLevel.ONE
);

ColumnPath colPath = new ColumnPath("Super1");
colPath.setSuper_column("attr".getBytes(UTF8));
colPath.setColumn("age".getBytes(UTF8));

Map<String, Map<String, List<Mutation>>> mutationMap = new HashMap<String, Map<String, List<Mutation>>>();

long timestamp = System.currentTimeMillis() * 1000;

{
  String key = "jsmith3";

  Map<String, List<Mutation>> colMap	= new HashMap<String, List<Mutation>>();
  addMutationColumn(colMap, "Standard2", "first".getBytes(UTF8), "John3".getBytes(UTF8),  timestamp);
  addMutationColumn(colMap, "Standard2", "last".getBytes(UTF8),  "Smith3".getBytes(UTF8), timestamp);
  addMutationColumn(colMap, "Standard2", "age".getBytes(UTF8),   "43".getBytes(UTF8),     timestamp);

  mutationMap.put(key, colMap);
}

client.batch_mutate("Keyspace1", mutationMap, ConsistencyLevel.ONE);

public static void addMutationColumn(
	Map<String, List<Mutation>> map,
	String columnFamily,
	byte[] name, byte[] value, long timestamp) {

  Column col = new Column(name, value, timestamp);

  ColumnOrSuperColumn cs = new ColumnOrSuperColumn()	.setColumn(col);
  Mutation mutation = new Mutation().setColumn_or_supercolumn(cs);

  List<Mutation> list = map.get(columnFamily);
  if (list == null) {
    list = new ArrayList<Mutation>();
    map.put(columnFamily, list);
  }
  list.add(mutation);
}

Map<String, Map<String, List<Mutation>>> mutationMap = new HashMap<String, Map<String, List<Mutation>>>();

long timestamp = System.currentTimeMillis() * 1000;

{
  String key = "jsmith4";

  Map<String, List<Mutation>> colMap = new HashMap<String, List<Mutation>>();
  addMutationSuperColumn(colMap, "Super1", "name".getBytes(UTF8), "first".getBytes(UTF8), "John4".getBytes(UTF8),  timestamp);
  addMutationSuperColumn(colMap, "Super1", "name".getBytes(UTF8), "last".getBytes(UTF8),  "Smith4".getBytes(UTF8), timestamp);
  addMutationSuperColumn(colMap, "Super1", "attr".getBytes(UTF8), "age".getBytes(UTF8),   "44".getBytes(UTF8),     timestamp);

  mutationMap.put(key, colMap);
}

client.batch_mutate("Keyspace1", mutationMap, ConsistencyLevel.ONE);

public static void addMutationSuperColumn(
	Map<String, List<Mutation>> map,
	String columnFamily,
	byte[] superName,
	byte[] name, byte[] value, long timestamp) {

  Column col = new Column(name, value, timestamp);
  SuperColumn scol = new SuperColumn().setName(superName);
  scol.addToColumns(col);

  ColumnOrSuperColumn cs = new ColumnOrSuperColumn().setSuper_column(scol);
  Mutation mutation = new Mutation().setColumn_or_supercolumn(cs);

  List<Mutation> list = map.get(columnFamily);
  if (list == null) {
    list = new ArrayList<Mutation>();
    map.put(columnFamily, list);
  }
  list.add(mutation);
}

String key = "jsmith2";

ColumnPath colPath = new ColumnPath("Standard2");

long timestamp = System.currentTimeMillis() * 1000;

client.remove(
  "Keyspace1", key, colPath, timestamp, ConsistencyLevel.ONE
);

Map<String, Map<String, List<Mutation>>> mutationMap
	= new HashMap<String, Map<String, List<Mutation>>>();

long timestamp = System.currentTimeMillis() * 1000;

Map<String, List<Mutation>> colMap = new HashMap<String, List<Mutation>>();
addDeletion(colMap, "Standard2",
  Arrays.asList(
    "first".getBytes(UTF8), "last".getBytes(UTF8), "age".getBytes(UTF8)
  ),
  timestamp
);
mutationMap.put("jsmith2", colMap);
mutationMap.put("jsmith3", colMap);

client.batch_mutate("Keyspace1", mutationMap, ConsistencyLevel.ONE);

public static void addDeletion(
	Map<String, List<Mutation>> map,
	String columnFamily,
	List<byte[]> names,
	long timestamp) {

  SlicePredicate predicate = new SlicePredicate().setColumn_names(names);
  Deletion deletion = new Deletion(timestamp).setPredicate(predicate);
  Mutation mutation = new Mutation().setDeletion(deletion);

  List<Mutation> list = map.get(columnFamily);
  if (list == null) {
    list = new ArrayList<Mutation>();
    map.put(columnFamily, list);
  }
  list.add(mutation);
}

Map<String, Map<String, List<Mutation>>> mutationMap
	= new HashMap<String, Map<String, List<Mutation>>>();

long timestamp = System.currentTimeMillis() * 1000;

Map<String, List<Mutation>> colMap = createDeletion(timestamp, "Standard2");
mutationMap.put("jsmith2", colMap);
mutationMap.put("jsmith3", colMap);

client.batch_mutate("Keyspace1", mutationMap, ConsistencyLevel.ONE);

public static Map<String, List<Mutation>> createDeletion(
	long timestamp,
	String... columnFamilies) {

  Deletion deletion = new Deletion(timestamp);
  Mutation mutation = new Mutation().setDeletion(deletion);

  List<Mutation> list = new ArrayList<Mutation>(1);
  list.add(mutation);

  Map<String, List<Mutation>> map
	= new HashMap<String, List<Mutation>>(columnFamilies.length);
  for (String columnFamily : columnFamilies) {
    map.put(columnFamily, list);
  }
  return map;
}

Map<String, Map<String, List<Mutation>>> mutationMap
	= new HashMap<String, Map<String, List<Mutation>>>();

long timestamp = System.currentTimeMillis() * 1000;

Map<String, List<Mutation>> colMap = new HashMap<String, List<Mutation>>();
addDeletionSuper(colMap, "Super1", "name".getBytes(UTF8), timestamp);
addDeletionSuper(colMap, "Super1", "attr".getBytes(UTF8), timestamp);

mutationMap.put("jsmith2", colMap);
mutationMap.put("jsmith4", colMap);

client.batch_mutate("Keyspace1", mutationMap, ConsistencyLevel.ONE);

public static void addDeletionSuper(
	Map<String, List<Mutation>> map,
	String columnFamily,
	byte[] superName,
	long timestamp) {

  Deletion deletion = new Deletion(timestamp).setSuper_column(superName);
  Mutation mutation = new Mutation().setDeletion(deletion);

  List<Mutation> list = map.get(columnFamily);
  if (list == null) {
    list = new ArrayList<Mutation>();
    map.put(columnFamily, list);
  }
  list.add(mutation);
}