%Library.GlobalStreamAdaptor
abstract stream class %Library.GlobalStreamAdaptor extends %Library.AbstractStream
Stream adaptor for streams that store data in global nodes. Not to be used directly.Method Inventory
- %Exists()
- %LocationGet()
- %LocationSet()
- %LockStream()
- %NormalizeObject()
- %ObjectIsNull()
- %ValidateObject()
- Clear()
- CopyFrom()
- Flush()
- GlobalFromSid()
- LastModifiedGet()
- MoveToEnd()
- OpenStream()
- OutputToDevice()
- Read()
- ReadLine()
- ReadLineIntoStream()
- Rewind()
- SaveStream()
- SizeGet()
- StreamOIDIsNull()
- Write()
Parameters
parameter BUFFERLEN = 163280;
Number of characters that we are storing in each global node
parameter STORAGE = GLOBAL;
parameter STOREGLOBALNAME = ^CacheStream;
Default location: can be overridden at run-time
Methods
classmethod %Exists(soid As %ObjectIdentity) as %Boolean
Inherited description: Checks to see if the object identified by the OID oid exists in the extent.
Returns %Boolean TRUE is it exists, FALSE if it does not.
method %LocationGet() as %String
method %LockStream()
%LockStream()
Obtain a shared lock on the current stream object. The return value is 1 if
the stream was already locked or if it was successfully locked. If the stream
cannot be locked the return value is 0.
This version of %LockStream differs from %Stream.Object only in the arguments passed
to %GetLockReference.
method %NormalizeObject() as %Status
Inherited description: Normalizes all of an object's property values by invoking the data type Normalize methods.
Many data types may allow many different representations of the same value.
Normalization converts a value to its cannonical, or normalized, form.
classmethod %ObjectIsNull(soid As %ObjectIdentity) as %Boolean
Return true if this stream oid is a null stream and false if the stream is not null
method %ValidateObject(force As %Library.Integer = 0, checkserial As %Library.Integer = 1) as %Status
Inherited description:
This method validates an object.
The %Save() method of a persistent class calls this method before filing any objects in the database. The %ValidateObject() of a referencing object can call it. You can also call it explicitly at any time.
%ValidateObject() does the following:
- If present, it will call a user-supplied %OnValidateObject() method.
- It checks if any required property values are missing.
- If the PROPERTYVALIDATION class parameter is set to ValidateOnSave, it validates each non-null property value by calling the property method IsValid on each literal property and the %ValidateObject method for each object-valued embedded object property (properties whose type extend %SerialObject).
- If checkserial is 1, it forces the checking of any embedded object properties by calling their %ValidateObject method after swizzling this property.
- If checkserial is 2, it forces the checking of any collections of serial types by iterating over those collections and calling their %ValidateObject() method after swizzling this property, in addition to the validation that occurs when checkserial is 1.
%ValidateObject() returns a %Status indicating success or error. It is up to the caller to process the error value.
%ValidateObject() does not validate object-valued reference properties (properties whose type extends %Persistent) due to the possibility of circular dependencies between objects. The %Save() method of a persistent class automatically detects and handles circular references between objects. If you require the validation of reference properties, you can override this method in a subclass or call %Save() directly.
Inherited description: Clear the contents of this Stream from permanent storage. This will remove the permanent stream storage and
any temporary stream and initialise the stream to its initial state that it starts in, including removing all
the stream attributes.
Returns a %Status value indicating success or failure.
method CopyFrom(source As %AbstractStream) as %Status
Inherited description: 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.
method Flush() as %Status
Inherited description: Flush any output in the stream not already saved.
Given a stream id this returns the root global node where this stream is stored
method LastModifiedGet() as %TimeStamp
method MoveToEnd() as %Status
Inherited description: Move to the end of the stream so the next Write() will be appended to the end.
This allows you to read from a stream, then MoveToEnd() and append new data, where just calling
Write() after a read will clear the stream before writing new data.
Returns a %Status value indicating success or failure.
Inherited description: Write out len characters of the stream to the current device starting from the current position. This
method is optimised for performance by the various sub classes. If len is omitted or set to -1 then
it will write out the entire stream starting at the beginning.
method Read(ByRef len As %Integer, ByRef sc As %Status) as %RawString
Inherited description: Read up to len characters from the current position
in the stream. The current position is advanced by the number of
characters read. Upon exit, len is set to the actual
number of characters read. If a read occurs when the stream position
is at the end of the stream, len will be set to -1 and
Read() will return a null string (""). If no len
is passed in, ie. 'Read()' then it is up to the Read implementation as to
how much data to return. Some stream classes use this to optimize the amount of
data returned to align this with the underlying storage of the stream.
You must call Rewind() if you want to read a stream from the beginning again. Calling Read() after Write() implicitly ends the Write() operation and rewinds to the start of the stream.
Returns a string up to len characters long. The byref argument sc will return a %Status if any error occurred during the read.
method ReadLine(ByRef len As %Integer = 32656, ByRef sc As %Status, ByRef eol As %Boolean) as %RawString
Inherited description: Read a line from the stream. This will look for the line terminator in the stream and
once it finds the terminator it will return the string minus the terminator character/s. If it reaches the
end of the stream before it finds a terminator it will return the data it has so far, and if you specify a
maximum size in len it will only read up to this number of characters. On exit len
will contain the actual number of characters read. The byref argument sc will
return a %Status() if any error occured during the read and the byref argument eol
is true if it found the line terminator and false otherwise. So for example you can read in a stream
a line at a time and output the results to the current device with:
While 'stream.AtEnd { Write stream.ReadLine(,.sc,.eol) If $$$ISERR(sc) { Write "ERROR" Quit } If eol { Write ! } }
method ReadLineIntoStream(ByRef sc As %Library.Status) as %AbstractStream
This reads from the stream until it find the LineTerminator and returns
this as a stream. If the stream does not contain the line terminator this can potentially be the
entire stream.
method Rewind() as %Status
Inherited description: Go back to the start of the stream.
method SaveStream() as %Status
Inherited description: Deprecated method, use %Save() instead.
Saves the temporary copy of the stream data to a persistent location. Note that
any locking or transaction handling must be done by the caller.
Returns a %Status value indicating success or failure.
method SizeGet() as %Integer
Return the current size of the data stream.
classmethod StreamOIDIsNull(soid As %ObjectIdentity) as %Boolean
Return true if this stream oid is a null stream and false if the stream is not null
method Write(data As %RawString = "") as %Status
Inherited description: Appends the string data to the stream and advances the
current stream position by the number of characters in data.
Note that a write operation immediately following a read or rewind will clear out the existing data in the stream.
Returns a %Status value indicating success or failure.
Inherited Members
Inherited Properties
Inherited Methods
- %AddToSaveSet()
- %CheckUnique()
- %ClassIsLatestVersion()
- %ClassName()
- %ConstructClone()
- %Delete()
- %DeleteExtent()
- %DeleteId()
- %DispatchClassMethod()
- %DispatchGetModified()
- %DispatchGetProperty()
- %DispatchMethod()
- %DispatchSetModified()
- %DispatchSetMultidimProperty()
- %DispatchSetProperty()
- %ExistsId()
- %Extends()
- %GetParameter()
- %GetSwizzleObject()
- %Id()
- %IsA()
- %IsModified()
- %IsNull()
- %KillExtent()
- %LOBPrefetch()
- %New()
- %ObjectModified()
- %ObjectSize()
- %Oid()
- %Open()
- %OpenId()
- %OriginalNamespace()
- %PackageName()
- %ReleaseLock()
- %Reload()
- %RemoveFromSaveSet()
- %RollBack()
- %Save()
- %SerializeObject()
- %SetModified()
- %UnlockStream()
- CopyFromAndSave()
- DeleteAttribute()
- DeleteStream()
- FindAt()
- GetAttribute()
- GetAttributeList()
- GetStreamId()
- InputFromDevice()
- IsCharacter()
- IsDefinedAttribute()
- IsNull()
- LineTerminatorSet()
- MoveTo()
- NextAttribute()
- OutputToDeviceAt()
- ReadSQL()
- SerializeToSyncSet()
- SetAttribute()
- SetAttributeList()
- SyncStreamIn()
- WriteLine()