IPdxInstance Interface

PdxInstance provides run time access to the fields of a PDX without deserializing the PDX. Preventing deserialization saves time and memory and does not require the domain class. This interface is implemented by NativeClient. The PdxInstance implementation is a light weight wrapper that simply refers to the raw bytes of the PDX that are kept in the cache. Applications can choose to access PdxInstances instead of .NET objects by configuring the Cache to prefer PDX instances during deserialization. This can be done in cache.xml by setting the attribute read-serialized to true on the pdx element. Or it can be done programmatically using the [!:CacheFactory.SetPdxReadSerialized] method. Once this preference is configured, then any time deserialization of a PDX is done it will deserialize into a PdxInstance. PdxInstance are immutable. If you want to change one call [!:IPdxInstance.CreateWriter].

Namespace: GemStone.GemFire.Cache.Generic
Assembly: Gemstone.Gemfire.Cache (in Gemstone.Gemfire.Cache.dll) Version: 9.0.6.18

Syntax

C++

Copy

public interface IPdxInstance : IDisposable

Public Interface IPdxInstance
	Inherits IDisposable

public interface class IPdxInstance : IDisposable

type IPdxInstance =  
    interface
        interface IDisposable
    end

The IPdxInstance type exposes the following members.

Methods

	Name	Description
	CreateWriter	Creates and returns a IWritablePdxInstance whose initial values are those of this PdxInstance. This call returns a copy of the current field values so modifications made to the returned value will not modify this PdxInstance.
	Dispose	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. (Inherited from IDisposable.)
	Equals	Returns true if the given object is equals to this instance. If Copy other is not a PdxInstance then it is not equal to this instance. NOTE: Even if Copy other is the result of calling GetObject it will not be equal to this instance. Otherwise equality of two PdxInstances is determined as follows: The domain class name must be equal for both PdxInstances Each identity field must be equal. If one of the instances does not have a field that the other one does then equals will assume it has the field with a default value. If a PdxInstance has marked identity fields using [!:IPdxWriter.MarkIdentityField] then only the marked identity fields are its identity fields. Otherwise all its fields are identity fields. An identity field is equal if all the following are true: The field name is equal. The field type is equal. The field value is equal. If a field's type is Copy OBJECT then its value must be deserialized to determine if it is equals. If the deserialized object is an array then all the array element is used to determine equality. Otherwise [!:Object.Equals] is used. If a field's type is Copy OBJECT[] then its value must be deserialized and all the array element is used to determine equality. For all other field types then the value does not need to be deserialized. Instead the serialized raw bytes are compared and used to determine equality. Note that any fields that have objects that do not override [!:Object.Equals] will cause equals to return false when you might have expected it to return true.
	GetClassName	Return the full name of the class that this pdx instance represents.
	GetField	Reads the named field and returns its value. If the field does not exist Copy null is returned. A Copy null result indicates that the field does not exist or that it exists and its value is currently Copy null . The HasField(String) method can be used to figure out which if these two cases is true. If an Object[] is deserialized by this call then that array's component type will be Copy Object instead of the original class that the array had when it was serialized. This is done so that PdxInstance objects can be added to the array.
	GetFieldNames	Return an list of the field names on this PdxInstance.
	GetHashCode	Generates a hashCode based on the identity fields of this PdxInstance. If a PdxInstance has marked identity fields using [!:IPdxWriter.MarkIdentityField] then only the marked identity fields are its identity fields. Otherwise all its fields are identity fields. If an identity field is of type Copy OBJECT then it is deserialized. If the deserialized object is an array then all the array element is used. Otherwise [!:Object.GetHashCode] is used. If an identity field is of type Copy OBJECT[] this it is deserialized and all the array element is used. Otherwise the field is not deserialized and the raw bytes of its value are used to compute the hash code.
	GetObject	Deserializes and returns the domain object that this instance represents.
	HasField	Checks if the named field exists and returns the result. This can be useful when writing code that handles more than one version of a PDX class.
	IsIdentityField	Checks if the named field was [!:IPdxWriter.MarkIdentityField] marked as an identity field. Note that if no fields have been marked then all the fields are used as identity fields even though this method will return Copy false since none of them have been marked.
	ToString	Prints out all of the identity fields of this PdxInstance. If a PdxInstance has marked identity fields using [!:IPdxWriter.MarkIdentityField] then only the marked identity fields are its identity fields. Otherwise all its fields are identity fields.

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Reference

GemStone.GemFire.Cache.Generic Namespace