Property Metadata
All the properties are written automatically into Space. If the field is a reference to another object, it has to be Serializable and it will be written into Space as well. Only the fields that need special space behavior need to be specified in the gs.xml file. Specify the fields that are IDs, indexes or need exclusions, etc.
GigaSpaces provides the ability to obtain and modify class metadata of objects stored in the Space during runtime.
Property
| Syntax | property name |
| Argument | name of the attribute |
| Description | contains mapping info for a property of a class |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false">
<property name="age" />
</class>
</gigaspaces-mapping>
SpaceProperty
| Syntax | null-value |
| Description | Specifies that an attribute value be treated as null when the object is written to the space and no value is assigned to the attribute. (where -1 functions as a null value in case of an int) |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false">
<property name="age" null-value="-1" />
<property name="status" null-value="-1" />
</class>
</gigaspaces-mapping>
Reference
| Syntax | reference |
| Argument | class name |
| Description | contains mapping information for a property of a class that is not primitive, but references another entity object. |
Example:
<gigaspaces-mapping>
<class name="Person">
<property name="firstName" />
<property name="address" reference="model.Address" />
</class>
</gigaspaces-mapping>
SpaceStorageType
| Syntax | storage-type |
| Argument | StorageType |
| Default | object |
| Description | This tag is used to specify how the property is stored in the space. |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false">
<property name="age" null-value="-1" />
<property name="address" storage-type="binary" />
</class>
</gigaspaces-mapping>
SpaceIndex
| Syntax | index type |
| Argument | SpaceIndexType |
| Description | Querying indexed fields speeds up read and take operations. The index tag should be used to specify an indexed field. |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false" >
<property name="lastName">
<index type="equal"/>
</property>
<property name="firstName">
<index type="equal"/>
</property>
<property name="age">
<index type="ordered"/>
</property>
</class>
</gigaspaces-mapping>
SpaceIndex Path
| Syntax | path type |
| Argument | SpaceIndexType |
| Description | The path attribute represents the path of the indexed property within a nested object. |
Example:
<gigaspaces-mapping>
<class name="model.Person" >
<property name="personalInfo">
<index path="socialSecurity" type = "ordered"/>
<index path="address.zipCode" type = "equal"/>
</property>
</class>
</gigaspaces-mapping>
Unique Index
| Syntax | index type unique |
| Argument | SpaceIndexType |
| Description | Unique constraints can be defined for an attribute or attributes of a Space class. |
| Note | The uniqueness is enforced per partition and not over the whole cluster. |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false" >
<property name="lastName">
<index type="EQUAL" unique="true"/>
</property>
<property name="firstName">
<index type="EQUAL"/>
</property>
<property name="age">
<index type="ORDERED"/>
</property>
</class>
</gigaspaces-mapping>
SpaceFifoGroupingIndex
| Syntax | fifo-grouping-index path |
| Description | This tag is used to define a space FIFO grouping Index. |
| Note | This tag can be declared on several properties in a class in order to assist in efficient traversal. If defined, there must be a property in the class, marked with the @SpaceFifoGroupingProperty annotation.A compound index that contains this FIFO grouping index and the FIFO grouping property will be created. |
Example:
<gigaspaces-mapping>
<class name="com.gigaspaces.examples.FlightReservation>
<property name="processingState">
<fifo-grouping-index />
</property>
<property name="customer">
<fifo-grouping-index path="id"/>
</property>
</class>
</gigaspaces-mapping>
SpaceId
| Syntax | id |
| Argument | auto-generate |
| Default | false |
| Description | Defines whether this field value is used when generating the Object ID. The field value should be unique – i.e., no multiple objects with the same value should be written into the space (each object should have a different field value). When writing an object into the space with an existing id field value, an EntryAlreadyInSpaceException is thrown. The Object ID is created, based on the id field value.Specifies if the object ID is generated automatically by the space when written into the space. If false, the field is indexed automatically, and if true, the field isn't indexed. If autoGenerate is declared as false, the field is indexed automatically. If autoGenerate is declared as true, the field isn't indexed. If autoGenerate is true, the field must be of the type java.lang.String. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="personId" />
<property name="firstName" />
<property name="lastName" />
<property name="type" />
<id name="personId" auto-generate="true" />
</class>
</gigaspaces-mapping>
[Space Object ID Operations(./space-object-id-operations.html)
SpaceRouting
| Syntax | routing |
| Description | The routing tag specifies a get method for the field to be used to calculate the target Space for the Space operation (read , write...). The routing field value hash code is used to calculate the target Space when the Space is running in partitioned mode.The field value hash code is used to calculate the target Space when the Space is running in partitioned mode. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="firstName" />
<property name="lastName" />
<property name="type" />
<id name="id" auto-generate="true" />
<routing name="type" />
</class>
</gigaspaces-mapping>
FIFO
Class Reference
| Syntax | class-ref |
| Argument | class name |
| Description | Contains the full qualified name of the specified class. |
Example:
<gigaspaces-mapping>
<class name="Person">
<property name="firstName" />
<property class-ref="model.Person" />
</class>
</gigaspaces-mapping>
SpacePersist
| Syntax | persist name="" |
| Description | This specifies a getter method for holding the persistency mode of the object overriding the class level persist declaration. This field should be of the boolean data type. If the persist class level annotation is true, all objects of this class type will be persisted into the underlying data store (Mirror, ExternalDataSource, Storage Adapter). |
| Note | When using this option, you must have the space class level persist decoration specified. |
Example:
<gigaspaces-mapping>
<class name="model.Person" persist="false" replicate="false">
<property name="age" null-value="-1" />
<persist name="persistence" />
</class>
</gigaspaces-mapping>
SpaceVersion
| Syntax | version |
| Description | This tag is used for object versioning used for optimistic locking. |
| Note | The attribute must be an int data type. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="versionId" />
<property name="firstName" />
<property name="lastName" />
<property name="type" />
<id name="id" auto-generate="true" />
<routing name="type" />
<version name="versionId" />
</class>
</gigaspaces-mapping>
SpaceExclude
| Syntax | exclude |
| Description | When this tag is specified the property is not written into the space. |
| Note | - When include-properties is defined as implicit, exclude should be used. This is because implicit instructs the system to take all POJO fields into account.- When include-properties is defined as explicit, there is no need to use exclude.- exclude can still be used, even if include-properties is not defined. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="firstName" />
<property name="lastName" />
<property name="type" />
<id name="id" auto-generate="true" />
<routing name="type" />
<exclude name="streetAddress" />
</class>
</gigaspaces-mapping>
SpaceLeaseExpiration
| Syntax | lease-expiration |
| Description | This tag specifies the property for holding the timestamp of when the instance's lease expires (this is a standard Java timestamp based on the 1/1/1970 epoch). This property should not be populated by the user code. The space will populate this property automatically based on the lease time given by the user when writing the object. When using an external data source, you can choose to persist this value to the database. Subsequently, when data is reloaded from the external data source (at startup time for example), the space will filter out instances whose lease expiration timestamp has already passed. This field should be a long data type. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="firstName" />
<property name="leaseExp" />
<property name="type" />
<id name="id" auto-generate="true" />
<routing name="type" />
<lease-expiration name="leaseExp" />
</class>
</gigaspaces-mapping>
SpaceFifoGroupingProperty
| Syntax | fifo-grouping-property path |
| Argument | path |
| Description | This tag is used to define a space FIFO grouping property. |
| Note | If defined, the TakeModifiers.FIFO_GROUPING_POLL or ReadModifiers.FIFO_GROUPING_POLL modifiers can be used to return all space entries that match the selection template in FIFO order. Different values of the FG property define groups of space entries that match each value. FIFO ordering exists within each group and not between different groups. |
Example:
<gigaspaces-mapping>
<class name="com.gigaspaces.examples.FlightReservation">
<fifo-grouping-property name="flightInfo" path=" flightNumber" />
</class>
</gigaspaces-mapping>
SpaceDynamicProperties
| Syntax | dynamic-properties |
| Description | Allows adding properties freely to a class without worrying about the schema. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="firstName" />
<property name="personInfo" />
<property name="type" />
<id name="id" auto-generate="true" />
<routing name="type" />
<dynamic-properties name="personInfo" />
</class>
</gigaspaces-mapping>
SpaceDocumentSupport
| Syntax | document-support |
| Description | If the POJO contains properties which are POJO themselves, the space will implicitly convert these properties to space documents as needed.This works the other way around as well - if a Space document is created with a nested space document property, it will be converted to a POJO with a nested POJO property when read as a POJO. You can disable this implicit conversion and preserve the nested POJO instance within document entries by setting it to copy |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="firstName" />
<property name="address" document-support="copy"/>
</class>
</gigaspaces-mapping>
Space Sequence Number
| Syntax | sequence-number |
| Description | A sequence number (like a data-base sequence-number/autoincrement column) is a property that is given a unique incrementing value when the entry is written to the Space. The sequence-number is unique per-partition. The property is of type Long. |
Example:
<gigaspaces-mapping>
<class name="model.Person">
<property name="id" />
<property name="sequenceNumber">
<property name="firstName" />
<sequence-number name="sequenceNumber" />
</class>
</gigaspaces-mapping>
