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abstract stream class %Library.AbstractStream extends %Stream.Object

Deprecated class, the base stream class is %Stream.Object. This is kept for legacy reasons.

A stream represents an arbitrary array of characters (or bytes) and a current position. The basic stream interface provides the ability to read data from a stream, write data to the stream, and rewind the current position to the beginning of the stream.

Within Caché streams are used to create large (greater than 32K) object attributes.

Property Inventory

Method Inventory


parameter MAXLEN = 2147483647;
The maximum number of characters (or bytes) allowed in a stream.
parameter MAXLOCALSIZE = 32000;
Turns off property validation.
final parameter READCHANGED = 2;
final parameter READNODATA = 0;
final parameter READNOTCHANGED = 1;
final parameter WRITE = 3;


property Attributes as %String [ MultiDimensional ];
An array of strings containing any attribute values associated with this stream.
Property methods: AttributesDisplayToLogical(), AttributesGet(), AttributesIsValid(), AttributesLogicalToDisplay(), AttributesLogicalToOdbc(), AttributesNormalize(), AttributesSet()
property LineTerminator as %String (MAXLEN = 10) [ InitialExpression = $char(13,10) ];
Type of line terminator we use for this stream, defaults to Cr/Lf. Maximum length is 10 characters. This is stored as an attribute of the stream called 'LineTerminator'.
Property methods: LineTerminatorDisplayToLogical(), LineTerminatorGet(), LineTerminatorIsValid(), LineTerminatorLogicalToDisplay(), LineTerminatorLogicalToOdbc(), LineTerminatorNormalize(), LineTerminatorSet()


method %Id() as %String
Returns the persistent object Id, if there is one, of this object.

Returns a null string if there is no object Id.

method %IsModified() as %Integer
Inherited description: Returns true (1) if a property of this instance has been modified, otherwise false (0). A TRUE result does not necessarily mean that any property has actually been changed. If %IsModified() returns false then the object has not been modified. There are some situations where we simply cannot efficiently detect a change in value. In these cases we will set the modified status of the property.
method %IsNull() as %Boolean
Returns true if this is a "NULL" stream; that is, a stream which has never been written to and saved. This is used by the Caché ODBC server.
method %ObjectModified() as %Integer
Inherited description: This method is somewhat similar to %IsModified but it also checks to see if swizzled references would cause the object to become modified should they be serialized. This works on the assumption that a reference to a persistent object will never be modified if the ID has already been assigned. For references to serial objects, a call to %ObjectModified indicates whether or not the serialized value is different. If the reference to a swizzled object is different from the initial object state then the $$$objModAll macro will already return true. Reference the Set code. Returns true (1) if this instance has been modified, otherwise false (0).
method CopyFrom(source As %Stream.Object) as %Status
Copies the contents of source into this Stream.

For example, you can copy oldstream into a new stream:

  Set newstream=##class(%GlobalCharacterStream).%New()
  Do newstream.CopyFrom(oldstream)

Returns a %Status value indicating success or failure.

final method DeleteAttribute(name As %String) as %Boolean
Removes this attribute variable from the collection. Returns true is it existed and false if it did not exist.
classmethod DeleteStream(oid As %ObjectIdentity, concurrency As %Integer = 0) as %Status
Deprecated method, use %Delete() instead. Deletes the stored stream identified by oid. This will not remove the stream attributes of any saved streams, it will just remove the stream data. If you need to clear the attributes as well you will have to call Clear() on the stream object.
method Flush() as %Status
Inherited description: Flush any output in the stream not already saved.
final method GetAttribute(name As %String, default As %String = "") as %String
Retrieves the named attribute value
method GetAttributeList() as %String
method GetStreamId() as %String
Returns an full id value (including class name) with which the Stream implementation has stored the stream.
final method IsDefinedAttribute(name As %String) as %Boolean
Returns true if the named attribute variable exists in the collection, false otherwise
method IsNull() as %Boolean