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https://issues.apache.org/jira/browse/FLINK-7452?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16167874#comment-16167874
]
ASF GitHub Bot commented on FLINK-7452:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/4612#discussion_r139113352
--- Diff:
flink-core/src/main/java/org/apache/flink/api/common/typeinfo/Types.java ---
@@ -19,56 +19,408 @@
package org.apache.flink.api.common.typeinfo;
import org.apache.flink.annotation.PublicEvolving;
+import org.apache.flink.api.common.functions.InvalidTypesException;
+import org.apache.flink.api.java.typeutils.EitherTypeInfo;
+import org.apache.flink.api.java.typeutils.EnumTypeInfo;
+import org.apache.flink.api.java.typeutils.GenericTypeInfo;
+import org.apache.flink.api.java.typeutils.ListTypeInfo;
+import org.apache.flink.api.java.typeutils.MapTypeInfo;
+import org.apache.flink.api.java.typeutils.ObjectArrayTypeInfo;
+import org.apache.flink.api.java.typeutils.PojoField;
+import org.apache.flink.api.java.typeutils.PojoTypeInfo;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
+import org.apache.flink.api.java.typeutils.TupleTypeInfo;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.api.java.typeutils.ValueTypeInfo;
-import java.math.BigDecimal;
-import java.sql.Date;
-import java.sql.Time;
-import java.sql.Timestamp;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
/**
- * This class gives access to the type information of the most most common
types.
+ * This class gives access to the type information of the most common
types for which Flink
+ * has built-in serializers and comparators.
+ *
+ * <p>In many cases, Flink tries to analyze generic signatures of
functions to determine return
+ * types automatically. This class is intended for cases where the
extraction is not possible
+ * (or inefficient) as well as cases where type information has to be
supplied manually.
+ *
+ * <p>Depending on the API you are using (e.g. Scala API or Table API),
there might be a more
+ * specialized <code>Types</code> class.
+ *
+ * <p>A more convenient alternative might be a {@link TypeHint}.
+ *
+ * @see TypeInformation#of(Class) specify type information based on a
class that will be analyzed
+ * @see TypeInformation#of(TypeHint) specify type information based on a
{@link TypeHint}
*/
@PublicEvolving
public class Types {
- public static final BasicTypeInfo<String> STRING =
BasicTypeInfo.STRING_TYPE_INFO;
- public static final BasicTypeInfo<Boolean> BOOLEAN =
BasicTypeInfo.BOOLEAN_TYPE_INFO;
- public static final BasicTypeInfo<Byte> BYTE =
BasicTypeInfo.BYTE_TYPE_INFO;
- public static final BasicTypeInfo<Short> SHORT =
BasicTypeInfo.SHORT_TYPE_INFO;
- public static final BasicTypeInfo<Integer> INT =
BasicTypeInfo.INT_TYPE_INFO;
- public static final BasicTypeInfo<Long> LONG =
BasicTypeInfo.LONG_TYPE_INFO;
- public static final BasicTypeInfo<Float> FLOAT =
BasicTypeInfo.FLOAT_TYPE_INFO;
- public static final BasicTypeInfo<Double> DOUBLE =
BasicTypeInfo.DOUBLE_TYPE_INFO;
- public static final BasicTypeInfo<BigDecimal> DECIMAL =
BasicTypeInfo.BIG_DEC_TYPE_INFO;
+ /**
+ * Returns type information for {@link java.lang.Void}. Does not
support a null value.
+ */
+ public static final TypeInformation<?> VOID =
BasicTypeInfo.VOID_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.lang.String}. Supports a
null value.
+ */
+ public static final TypeInformation<?> STRING =
BasicTypeInfo.STRING_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>byte</code> and a
+ * wrapped {@link java.lang.Byte}. Does not support a null value.
+ */
+ public static final TypeInformation<?> BYTE =
BasicTypeInfo.BYTE_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>boolean</code>
and a
+ * wrapped {@link java.lang.Boolean}. Does not support a null value.
+ */
+ public static final TypeInformation<?> BOOLEAN =
BasicTypeInfo.BOOLEAN_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>short</code> and
a
+ * wrapped {@link java.lang.Short}. Does not support a null value.
+ */
+ public static final TypeInformation<?> SHORT =
BasicTypeInfo.SHORT_TYPE_INFO;
- public static final SqlTimeTypeInfo<Date> SQL_DATE =
SqlTimeTypeInfo.DATE;
- public static final SqlTimeTypeInfo<Time> SQL_TIME =
SqlTimeTypeInfo.TIME;
- public static final SqlTimeTypeInfo<Timestamp> SQL_TIMESTAMP =
SqlTimeTypeInfo.TIMESTAMP;
+ /**
+ * Returns type information for both a primitive <code>int</code> and a
+ * wrapped {@link java.lang.Integer}. Does not support a null value.
+ */
+ public static final TypeInformation<?> INT =
BasicTypeInfo.INT_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>long</code> and a
+ * wrapped {@link java.lang.Long}. Does not support a null value.
+ */
+ public static final TypeInformation<?> LONG =
BasicTypeInfo.LONG_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>float</code> and
a
+ * wrapped {@link java.lang.Float}. Does not support a null value.
+ */
+ public static final TypeInformation<?> FLOAT =
BasicTypeInfo.FLOAT_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>double</code>
and a
+ * wrapped {@link java.lang.Double}. Does not support a null value.
+ */
+ public static final TypeInformation<?> DOUBLE =
BasicTypeInfo.DOUBLE_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>char</code> and a
+ * wrapped {@link java.lang.Character}. Does not support a null value.
+ */
+ public static final TypeInformation<?> CHAR =
BasicTypeInfo.CHAR_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.math.BigDecimal}. Supports
a null value.
+ */
+ public static final TypeInformation<?> BIG_DEC =
BasicTypeInfo.BIG_DEC_TYPE_INFO;
/**
- * Generates a RowTypeInfo with fields of the given types.
- * The fields have the default names (f0, f1, f2 ..).
+ * Returns type information for {@link java.math.BigInteger}. Supports
a null value.
+ */
+ public static final TypeInformation<?> BIG_INT =
BasicTypeInfo.BIG_INT_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.sql.Date}. Supports a null
value.
+ */
+ public static final TypeInformation<?> SQL_DATE = SqlTimeTypeInfo.DATE;
+
+ /**
+ * Returns type information for {@link java.sql.Time}. Supports a null
value.
+ */
+ public static final TypeInformation<?> SQL_TIME = SqlTimeTypeInfo.TIME;
+
+ /**
+ * Returns type information for {@link java.sql.Timestamp}. Supports a
null value.
+ */
+ public static final TypeInformation<?> SQL_TIMESTAMP =
SqlTimeTypeInfo.TIMESTAMP;
+
+ /**
+ * Returns type information for {@link org.apache.flink.types.Row} with
fields of the given types.
+ * A row itself must not be null.
+ *
+ * <p>A row is a variable-length, null-aware composite type for storing
multiple values in a
+ * deterministic field order. Every field can be null independent of
the field's type.
+ * Fields of a row are untyped; therefore, it is required to pass type
information whenever a row is used.
*
- * <p>This method is a shortcut to {@code new RowTypeInfo(types)}.
+ * <p>This method generates type information with fields of the given
types; the fields have
+ * the default names (f0, f1, f2 ..).
*
* @param types The types of the row fields, e.g., Types.STRING,
Types.INT
*/
- public static RowTypeInfo ROW(TypeInformation<?>... types) {
+ public static TypeInformation<?> ROW(TypeInformation<?>... types) {
return new RowTypeInfo(types);
}
/**
- * Generates a RowTypeInfo with fields of the given types and with
given names.
- *
+ * Returns type information for {@link org.apache.flink.types.Row} with
fields of the given types and
+ * with given names. A row must not be null.
+ *
+ * <p>A row is a variable-length, null-aware composite type for storing
multiple values in a
+ * deterministic field order. Every field can be null independent of
the field's type.
+ * Fields of a row are untyped; therefore, it is required to pass type
information whenever a row is used.
+ *
* <p>Example use: {@code ROW_NAMED(new String[]{"name", "number"},
Types.STRING, Types.INT)}.
- *
- * <p>This method is identical to {@code new RowTypeInfo(types, names)}.
*
* @param fieldNames array of field names
* @param types array of field types
*/
- public static RowTypeInfo ROW_NAMED(String[] fieldNames,
TypeInformation<?>... types) {
+ public static TypeInformation<?> ROW_NAMED(String[] fieldNames,
TypeInformation<?>... types) {
return new RowTypeInfo(types, fieldNames);
}
+
+ /**
+ * Returns type information for subclasses of Flink's {@link
org.apache.flink.api.java.tuple.Tuple}
+ * (namely {@link org.apache.flink.api.java.tuple.Tuple0} till {@link
org.apache.flink.api.java.tuple.Tuple25})
+ * with fields of the given types. A tuple must not be null.
+ *
+ * <p>A tuple is a fixed-length composite type for storing multiple
values in a
+ * deterministic field order. Fields of a tuple are typed. Tuples are
the most efficient composite
+ * type; therefore, a tuple does not support null values unless its
field type supports nullability.
+ *
+ * @param types The types of the tuple fields, e.g., Types.STRING,
Types.INT
+ */
+ public static TypeInformation<?> TUPLE(TypeInformation<?>... types) {
+ return new TupleTypeInfo<>(types);
+ }
+
+ /**
+ * Returns type information for typed subclasses of Flink's {@link
org.apache.flink.api.java.tuple.Tuple}.
+ * Typed subclassed are classes that extend {@link
org.apache.flink.api.java.tuple.Tuple0} till
+ * {@link org.apache.flink.api.java.tuple.Tuple25} to provide types for
all fields and might add
+ * additional getters and setters for better readability. A tuple must
not be null.
+ *
+ * <p>A tuple is a fixed-length composite type for storing multiple
values in a
+ * deterministic field order. Fields of a tuple are typed. Tuples are
the most efficient composite
+ * type; therefore, a tuple does not support null values unless a field
type supports nullability.
+ *
+ * <p>Types for all fields of the tuple can be defined in a hierarchy
of subclasses.
+ *
+ * <p>If Flink's type analyzer is unable to extract a tuple type
information with
+ * type information for all fields, an {@link
org.apache.flink.api.common.functions.InvalidTypesException}
+ * is thrown.
+ *
+ * <p>Example use:
+ * <pre>
+ * {@code
+ * class MyTuple extends Tuple2<Integer, String> {
+ *
+ * public int getId() { return f0; }
+ *
+ * public String getName() { return f1; }
+ * }
+ * }
+ *
+ * Types.TUPLE(MyTuple.class)
+ * </pre>
+ *
+ * @param tupleSubclass A subclass of {@link
org.apache.flink.api.java.tuple.Tuple0} till
+ * {@link org.apache.flink.api.java.tuple.Tuple25}
that defines all field types and
+ * does not add any additional fields
+ */
+ public static TypeInformation<?> TUPLE(Class<?> tupleSubclass) {
+ final TypeInformation<?> ti =
TypeExtractor.createTypeInfo(tupleSubclass);
+ if (ti instanceof TupleTypeInfo) {
+ return ti;
+ }
+ throw new InvalidTypesException("Tuple type expected but was: "
+ ti);
+ }
+
+ /**
+ * Returns type information for a POJO (Plain Old Java Object).
+ *
+ * <p>A POJO class is public and standalone (no non-static inner
class). It has a public no-argument
+ * constructor. All non-static, non-transient fields in the class (and
all superclasses) are either public
+ * (and non-final) or have a public getter and a setter method that
follows the Java beans naming
+ * conventions for getters and setters.
+ *
+ * <p>A POJO is a fixed-length, null-aware composite type with
non-deterministic field order. Every field
--- End diff --
At which point is the field order important for users? Isn't it only
relevant if you are dealing with the serialization format or when you want to
map fields to a different type (as we do in the Table API)?
> Add helper methods for all built-in Flink types to Types
> --------------------------------------------------------
>
> Key: FLINK-7452
> URL: https://issues.apache.org/jira/browse/FLINK-7452
> Project: Flink
> Issue Type: Improvement
> Components: Type Serialization System
> Reporter: Timo Walther
> Assignee: Timo Walther
>
> Sometimes it is very difficult to provide `TypeInformation` manually, in case
> some extraction fails or is not available. {{TypeHint}}s should be the
> preferred way but this methods can ensure correct types.
> I propose to add all built-in Flink types to the {{Types}}. Such as:
> {code}
> Types.POJO(MyPojo.class)
> Types.POJO(Map<String, TypeInformation>)
> Types.GENERIC(Object.class)
> Types.TUPLE(TypeInformation, ...)
> Types.MAP(TypeInformation, TypeInformation)
> {code}
> The methods should validate that the returned type is exactly the requested
> type. And especially in case of POJO should help creating {{PojoTypeInfo}}.
> Once this is in place, we can deprecate the {{TypeInfoParser}}.
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