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https://issues.apache.org/jira/browse/FLINK-7452?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16291073#comment-16291073
]
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_r156951434
--- Diff:
flink-core/src/main/java/org/apache/flink/api/common/typeinfo/Types.java ---
@@ -19,56 +19,422 @@
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.tuple.Tuple;
+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 org.apache.flink.types.Either;
+import org.apache.flink.types.Row;
+import org.apache.flink.types.Value;
+import java.lang.reflect.Field;
import java.math.BigDecimal;
+import java.math.BigInteger;
import java.sql.Date;
import java.sql.Time;
import java.sql.Timestamp;
+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 type
information has to be
+ * supplied manually or would result in an inefficient type.
+ *
+ * <p>Please note that the Scala API and Table API provide more
specialized Types classes.
+ * (See <code>org.apache.flink.api.scala.Types</code> and
<code>org.apache.flink.table.api.Types</code>)
+ *
+ * <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> VOID =
BasicTypeInfo.VOID_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.lang.String}. Supports a
null value.
+ */
+ public static final TypeInformation<String> STRING =
BasicTypeInfo.STRING_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>byte</code> and
{@link java.lang.Byte}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Byte> BYTE =
BasicTypeInfo.BYTE_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>boolean</code>
and {@link java.lang.Boolean}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Boolean> BOOLEAN =
BasicTypeInfo.BOOLEAN_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>short</code> and
{@link java.lang.Short}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Short> SHORT =
BasicTypeInfo.SHORT_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>int</code> and
{@link java.lang.Integer}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Integer> INT =
BasicTypeInfo.INT_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>long</code> and
{@link java.lang.Long}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Long> LONG =
BasicTypeInfo.LONG_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>float</code> and
{@link java.lang.Float}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Float> FLOAT =
BasicTypeInfo.FLOAT_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>double</code>
and {@link java.lang.Double}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Double> DOUBLE =
BasicTypeInfo.DOUBLE_TYPE_INFO;
+
+ /**
+ * Returns type information for both a primitive <code>char</code> and
{@link java.lang.Character}.
+ * Does not support a null value.
+ */
+ public static final TypeInformation<Character> CHAR =
BasicTypeInfo.CHAR_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.math.BigDecimal}. Supports
a null value.
+ */
+ public static final TypeInformation<BigDecimal> BIG_DEC =
BasicTypeInfo.BIG_DEC_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.math.BigInteger}. Supports
a null value.
+ */
+ public static final TypeInformation<BigInteger> BIG_INT =
BasicTypeInfo.BIG_INT_TYPE_INFO;
+
+ /**
+ * Returns type information for {@link java.sql.Date}. Supports a null
value.
+ */
+ public static final TypeInformation<Date> SQL_DATE =
SqlTimeTypeInfo.DATE;
+
+ /**
+ * Returns type information for {@link java.sql.Time}. Supports a null
value.
+ */
+ public static final TypeInformation<Time> SQL_TIME =
SqlTimeTypeInfo.TIME;
- 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 {@link java.sql.Timestamp}. Supports a
null value.
+ */
+ public static final TypeInformation<Timestamp> SQL_TIMESTAMP =
SqlTimeTypeInfo.TIMESTAMP;
/**
- * Generates a RowTypeInfo with fields of the given types.
- * The fields have the default names (f0, f1, f2 ..).
+ * 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 fixed-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.
+ * The type of row fields cannot be automatically inferred; therefore,
it is required to pass
+ * type information whenever a row is used.
+ *
+ * <p>The schema of rows can have up to <code>Integer.MAX_VALUE</code>
fields, however, all row instances
+ * must have the same length otherwise serialization fails or
information is lost.
*
- * <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> 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 fixed-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.
+ * The type of row fields cannot be automatically inferred; therefore,
it is required to pass
+ * type information whenever a row is used.
+ *
+ * <p>The schema of rows can have up to <code>Integer.MAX_VALUE</code>
fields, however, all row instances
+ * must have the same length otherwise serialization fails or
information is lost.
+ *
* <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> 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; 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 <T extends Tuple> TypeInformation<T>
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. Additional
member fields must not be added.
+ * 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; a tuple does not support null values unless a field type
supports nullability.
+ *
+ * <p>The generic 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 <T extends Tuple> TypeInformation<T> TUPLE(Class<T>
tupleSubclass) {
+ final TypeInformation<T> 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
+ * can be null independent of the field's type.
+ *
+ * <p>The generic types for all fields of the POJO can be defined in a
hierarchy of subclasses.
+ *
+ * <p>If Flink's type analyzer is unable to extract a valid POJO type
information with
+ * type information for all fields, an {@link
org.apache.flink.api.common.functions.InvalidTypesException}
+ * is thrown. Alternatively, you can use {@link Types#POJO(Class, Map)}
to specify all fields manually.
+ *
+ * @param pojoClass POJO class to be analyzed by Flink
+ */
+ public static <T> TypeInformation<T> POJO(Class<T> pojoClass) {
+ final TypeInformation<T> ti =
TypeExtractor.createTypeInfo(pojoClass);
+ if (ti instanceof PojoTypeInfo) {
+ return ti;
+ }
+ throw new InvalidTypesException("POJO type expected but was: "
+ ti);
+ }
+
+ /**
+ * Returns type information for a POJO (Plain Old Java Object) and
allows to specify all fields manually.
+ *
+ * <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
+ * can be null independent of the field's type.
+ *
+ * <p>The generic types for all fields of the POJO can be defined in a
hierarchy of subclasses.
+ *
+ * <p>If Flink's type analyzer is unable to extract a POJO field, an
+ * {@link org.apache.flink.api.common.functions.InvalidTypesException}
is thrown.
+ *
+ * <p><strong>Note:</strong> In most cases the type information of
fields can be determined automatically,
+ * we recommend to use {@link Types#POJO(Class)}.
+ *
+ * @param pojoClass POJO class
+ * @param fields map of fields that map a name to type information
+ */
+ public static <T> TypeInformation<T> POJO(Class<T> pojoClass,
Map<String, TypeInformation<?>> fields) {
+ final List<PojoField> pojoFields = new
ArrayList<>(fields.size());
+ for (Map.Entry<String, TypeInformation<?>> field :
fields.entrySet()) {
+ Field f = TypeExtractor.getDeclaredField(pojoClass,
field.getKey());
+ if (f == null) {
+ throw new InvalidTypesException("Field '" +
field.getKey() + "'could not be accessed.");
+ }
+ pojoFields.add(new PojoField(f, field.getValue()));
+ }
+
+ return new PojoTypeInfo<>(pojoClass, pojoFields);
+ }
+
+ /**
+ * Returns generic type information for any Java object. The
serialization logic will
+ * use the general purpose serializer Kryo.
+ *
+ * <p>Generic types are black-boxes for Flink, but allow any object and
null values in fields.
+ *
+ * <p>By default, serialization of this type is not very efficient.
Please read the documentation
+ * about how to improve efficiency (namely by pre-registering classes).
+ *
+ * @param genericClass any Java class
+ */
+ public static <T> TypeInformation<T> GENERIC(Class<T> genericClass) {
+ return new GenericTypeInfo<>(genericClass);
+ }
+
+ /**
+ * Returns type information for Java arrays of primitive type (such as
<code>byte[]</code>). The array
+ * must not be null.
+ *
+ * @param elementType element type of the array (e.g. Types.BOOLEAN,
Types.INT, Types.DOUBLE)
+ */
+ public static TypeInformation<?> PRIMITIVE_ARRAY(TypeInformation<?>
elementType) {
+ if (elementType == BOOLEAN) {
+ return
PrimitiveArrayTypeInfo.BOOLEAN_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == BYTE) {
+ return
PrimitiveArrayTypeInfo.BYTE_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == SHORT) {
+ return
PrimitiveArrayTypeInfo.SHORT_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == INT) {
+ return
PrimitiveArrayTypeInfo.INT_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == LONG) {
+ return
PrimitiveArrayTypeInfo.LONG_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == FLOAT) {
+ return
PrimitiveArrayTypeInfo.FLOAT_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == DOUBLE) {
+ return
PrimitiveArrayTypeInfo.DOUBLE_PRIMITIVE_ARRAY_TYPE_INFO;
+ } else if (elementType == CHAR) {
+ return
PrimitiveArrayTypeInfo.CHAR_PRIMITIVE_ARRAY_TYPE_INFO;
+ }
+ throw new IllegalArgumentException("Invalid element type for a
primitive array.");
+ }
+
+ /**
+ * Returns type information for Java arrays of object types (such as
<code>String[]</code>,
+ * <code>Integer[]</code>). The array itself must not be null. Null
values for elements are supported.
+ *
+ * @param elementType element type of the array
+ */
+ @SuppressWarnings("unchecked")
+ public static <E> TypeInformation<E[]> OBJECT_ARRAY(TypeInformation<E>
elementType) {
+ if (elementType == Types.STRING) {
+ return (TypeInformation)
BasicArrayTypeInfo.STRING_ARRAY_TYPE_INFO;
+ }
+ return ObjectArrayTypeInfo.getInfoFor(elementType);
+ }
+
+ /**
+ * Returns type information for Flink value types (classes that
implement
+ * {@link org.apache.flink.types.Value}). Built-in value types do not
support null values.
+ *
+ * <p>Value types describe their serialization and deserialization
manually. Instead of going
+ * through a general purpose serialization framework. A value type is
reasonable when general purpose
+ * serialization would be highly inefficient. The wrapped value can be
altered, allowing programmers to
+ * reuse objects and take pressure off the garbage collector.
+ *
+ * <p>Flink provides built-in value types for all Java primitive types
(such as
+ * {@link org.apache.flink.types.BooleanValue}, {@link
org.apache.flink.types.IntValue}) as well
+ * as {@link org.apache.flink.types.StringValue}, {@link
org.apache.flink.types.NullValue},
+ * {@link org.apache.flink.types.ListValue}, and {@link
org.apache.flink.types.MapValue}.
+ *
+ * @param valueType class that implements {@link
org.apache.flink.types.Value}
+ */
+ public static <V extends Value> TypeInformation<V> VALUE(Class<V>
valueType) {
+ return new ValueTypeInfo<>(valueType);
+ }
+
+ /**
+ * Returns type information for a Java {@link java.util.Map}. A map
must not be null. Null values
+ * in keys are not supported. An entry's value can be null.
+ *
+ * <p>By default, maps are untyped and treated as a generic type in
Flink; therefore, it is useful
+ * to pass type information whenever a map is used.
+ *
+ * @param keyType type information for the map's keys
+ * @param valueType type information for the map's values
+ */
+ public static <K, V> TypeInformation<Map<K, V>> MAP(TypeInformation<K>
keyType, TypeInformation<V> valueType) {
--- End diff --
Do we want to mention, that Flink does not preserve the concrete `Map`
type?
It converts all `Map` into `HashMap` when copying or deserializing.
> 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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