com.datasalt.pangool.io
Class Schema.Field

java.lang.Object
  com.datasalt.pangool.io.Schema.Field

All Implemented Interfaces:

Serializable

Enclosing class:

Schema

public static class Schema.Field
extends Object
implements Serializable

A field is an abstract data type that can be one of this:

• A 32-bit signed int;
• A 64-bit signed long;
• A 32-bit IEEE single-float; or
• A 64-bit IEEE double-float; or
• A unicode string;
• A boolean; or
• An enum, containing one of a small set of symbols;
• A byte buffer
• An arbitrary object, serializable by Hadoop's serialization

A field can be constructed using one of its static createXXX methods. A field object is immutable.

See Also:

Serialized Form

Nested Class Summary

static interface	Schema.Field.FieldConfigurable Interface that allows to receive ITuple field's metadata.
static class	Schema.Field.Type

Field Summary

static String	METADATA_BYTES_AS_OBJECT
static String	METADATA_DEFAULT_VALUE
static String	METADATA_OBJECT_CLASS
static String	METADATA_OBJECT_SERIALIZATION
static Set<String>	RESERVED_KEYWORDS

Method Summary

void	addProp(String key, String value)
static Schema.Field	cloneField(Schema.Field field, String newName) Clones a Field with a new name.
static Schema.Field	cloneField(Schema.Field field, String newName, boolean nullable) Clones a Field with a new name.
static Schema.Field	create(String name, Schema.Field.Type type) Crates a non nullable field of the given type.
static Schema.Field	create(String name, Schema.Field.Type type, boolean nullable) Crates a field of the given type.
static Schema.Field	create(String name, Schema.Field.Type type, boolean nullable, Object defaultValue) Crates a field of the given type.
static Schema.Field	createEnum(String name, Class<?> clazz) Creates a non-nullable enum field, based in a enum class
static Schema.Field	createEnum(String name, Class<?> clazz, boolean nullable) Creates an enum field, based in a enum class
static Schema.Field	createEnum(String name, Class<?> clazz, boolean nullable, Object defaultValue) Creates an enum field, based in a enum class
static Schema.Field	createObject(String name, Class<?> clazz) Creates a non nullable object field.
static Schema.Field	createObject(String name, Class<?> clazz, boolean nullable) Creates an object field.
static Schema.Field	createTupleField(String name, Schema schema) Creates a non-nullable field containing a Pangool Tuple.
static Schema.Field	createTupleField(String name, Schema schema, boolean nullable) Creates a field containing a Pangool Tuple.
boolean	equals(Object a)
Object	getDefaultValue()
String	getName()
Class<?>	getObjectClass()
Class<? extends org.apache.hadoop.io.serializer.Serialization>	getObjectSerialization()
String	getProp(String name)
Map<String,String>	getProps()
Schema.Field.Type	getType()
int	hashCode()
boolean	isNullable()
void	setObjectSerialization(Class<? extends org.apache.hadoop.io.serializer.Serialization> serialization) Sets custom serialization for fields with type OBJECT.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

RESERVED_KEYWORDS

public static final Set<String> RESERVED_KEYWORDS

METADATA_OBJECT_CLASS

public static final String METADATA_OBJECT_CLASS

See Also:

Constant Field Values

METADATA_OBJECT_SERIALIZATION

public static final String METADATA_OBJECT_SERIALIZATION

See Also:

Constant Field Values

METADATA_BYTES_AS_OBJECT

public static final String METADATA_BYTES_AS_OBJECT

See Also:

Constant Field Values

METADATA_DEFAULT_VALUE

public static final String METADATA_DEFAULT_VALUE

See Also:

Constant Field Values

Method Detail

addProp

public void addProp(String key,
                    String value)

getProps

public Map<String,String> getProps()

getProp

public String getProp(String name)

create

public static Schema.Field create(String name,
                                  Schema.Field.Type type,
                                  boolean nullable,
                                  Object defaultValue)

Crates a field of the given type.

Parameters:

name - Field's name

type - Schema.Field.Type of the field

nullable - True if null values are allowed for this field

defaultValue - The default value for this field if the field is missing in some read schema

create

public static Schema.Field create(String name,
                                  Schema.Field.Type type,
                                  boolean nullable)

Crates a field of the given type.

Parameters:

name - Field's name

type - Schema.Field.Type of the field

nullable - True if null values are allowed for this field

create

public static Schema.Field create(String name,
                                  Schema.Field.Type type)

Crates a non nullable field of the given type.

Parameters:

name - Field's name

type - Schema.Field.Type of the field

createObject

public static Schema.Field createObject(String name,
                                        Class<?> clazz,
                                        boolean nullable)

Creates an object field.

Parameters:

name - Field's name

clazz - Object's instance class

nullable - True if null values are allowed for this field

createObject

public static Schema.Field createObject(String name,
                                        Class<?> clazz)

Creates a non nullable object field.

Parameters:

name - Field's name

clazz - Object's instance class

Returns:

createTupleField

public static Schema.Field createTupleField(String name,
                                            Schema schema,
                                            boolean nullable)

Creates a field containing a Pangool Tuple.

Parameters:

name - Field's name

schema - The schema of the field

nullable - True if null values are allowed for this field

Returns:

createTupleField

public static Schema.Field createTupleField(String name,
                                            Schema schema)

Creates a non-nullable field containing a Pangool Tuple.

Parameters:

name - Field's name

schema - The schema of the field

Returns:

cloneField

public static Schema.Field cloneField(Schema.Field field,
                                      String newName,
                                      boolean nullable)

Clones a Field with a new name. Useful for mutating schemas.

Parameters:

field - The field to clone.

newName - The new name of the field.

nullable - If the new field must be nullable or not

Returns:

The cloned field.

cloneField

public static Schema.Field cloneField(Schema.Field field,
                                      String newName)

Clones a Field with a new name. Useful for mutating schemas.

Parameters:

field - The field to clone.

newName - The new name of the field.

Returns:

The cloned field.

createEnum

public static Schema.Field createEnum(String name,
                                      Class<?> clazz,
                                      boolean nullable,
                                      Object defaultValue)

Creates an enum field, based in a enum class

Parameters:

name - Field's name

clazz - Enum class

nullable - True if null values are allowed for this field.

defaultValue - The defaultValue to assign if this field is not present in some read schema.

Returns:

createEnum

public static Schema.Field createEnum(String name,
                                      Class<?> clazz,
                                      boolean nullable)

Creates an enum field, based in a enum class

Parameters:

name - Field's name

clazz - Enum class

nullable - True if null values are allowed for this field.

Returns:

createEnum

public static Schema.Field createEnum(String name,
                                      Class<?> clazz)

Creates a non-nullable enum field, based in a enum class

Parameters:

name - Field's name

clazz - Enum class

Returns:

getDefaultValue

public Object getDefaultValue()

Returns:

Null if this field has no associated default value, or the strongly typed default value otherwise. Default values can be set by Field constructor and are enforced to its corret type, then serialized to string.

getType

public Schema.Field.Type getType()

getName

public String getName()

getObjectClass

public Class<?> getObjectClass()

isNullable

public boolean isNullable()

getObjectSerialization

public Class<? extends org.apache.hadoop.io.serializer.Serialization> getObjectSerialization()

setObjectSerialization

public void setObjectSerialization(Class<? extends org.apache.hadoop.io.serializer.Serialization> serialization)

Sets custom serialization for fields with type OBJECT. If the Serialization class also implements Schema.Field.FieldConfigurable then the field's metadata (properties) is passed to the instance allowing stateful serialization.

equals

public boolean equals(Object a)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object