DataStream5250 (NetPhantom® 7.7 Java API Specification)

java.lang.Object
- se.entra.phantom.server.tn5250e.DataStream5250

```
public class DataStream5250
extends Object
```
This class handles the 5250 data stream.
The complete list of 5250 terminal types is maintained in the Assigned Numbers RFC and includes the following:
```
  .    IBM-5555-C01   24 x 80 Double-Byte Character Set color display
  .    IBM-5555-B01   24 x 80 Double-Byte Character Set (DBCS)
  (*)  IBM-3477-FC    27 x 132 color display
  (*)  IBM-3477-FG    27 x 132 monochrome display
  (*)  IBM-3180-2     27 x 132 monochrome display
  (*)  IBM-3179-2     24 x 80 color display
  (*)  IBM-3196-A1    24 x 80 monochrome display
  (*)  IBM-5292-2     24 x 80 color display
  (*)  IBM-5291-1     24 x 80 monochrome display
  (*)  IBM-5251-11    24 x 80 monochrome display
 
```
The supported terminal types are marked with (*) above. To determin if the terminal type is of 27 x 132 type, the terminal name must contain "3477-" or "3180-".
5250 Data Stream Enhancements

This section is intended to be used as an addendum to the IBM 5250 Information Display System, Functions Reference Manual. Described here are enhancements to the 5250 data stream which are not yet documented in the current version of that manual. The current version of that manual at the time of this writing has the IBM publication number SA21-9247-6. Also described in this section are corrections to erroneous information contained in SA21-9247-6.
Listed below are the specific corrections and enhancements, with an approximate page number reference to the above manual.
Errors or Inconsistencies in SA21-9247-6

The Insert Cursor (IC) order on pages 2-136 and 2-137 is incorrectly listed with a value of Hex 03; the correct value is Hex 13. On page 2-137, the listed "Restrictions" for the Insert Cursor, Repeat to Address, and Set Buffer Address orders should be updated to describe how Row and Column values must be valid for the current display screen size (either 24 x 80 or 27 x 132).
Enhancements to Existing 5250 Data Stream Commands/Orders

A new flag is added to the second byte of the Control Character on page 2-40. This flag is used to specify whether the cursor should be moved or not moved at the end of the Write to Display processing. Bit 1 of the second byte, which was previously reserved, will now be used for this flag. If bit 1 is a 0, the cursor continues to be moved to the system IC address on a Lock-to-Unlock keyboard transition. If bit 1 is a 1, the cursor is not moved.
A new Field Control Word (FCW) will be added on page 2-65 to indicate an entry field contains transparent data. This means the entry field contents are sent from the display screen directly to the host at read time with no formatting. Therefore, an entry field can contain any values (Hex 00 to Hex FF). A transparent field is indicated by a Hex 84xx FCW, where xx is any value. Note: unpredictable results will occur if a field is defined as both signed numeric and a transparent field.
The Read Immediate, Read Input Fields, and Read MDT Fields commands have been enhanced to include support for transparent fields (page 2-5). If a transparent FCW is found for an input field, the field data is not formatted (for example, nulls are not converted to blanks).
The restriction listed for the Set Buffer Address (SBA) order (page 2-138) on the column address equal to zero is no longer always the case. A reference to Start of Field (SF) row 1/column 1 field support should be made. A note should be added in SF to describe Row 1/Column 1 field support. A Row 1/Column 1 field is defined by a SBA of row 1/column 0, followed by an SF. For a Row 1/Column 1 input field, the first input-capable position is row 1/column 1. If the SF defines an input field, the screen attribute is not allowed to be nondisplay. Writing of the screen attribute is suppressed for a Row 1/Column 1 field and the attribute discarded.
New 5250 Data Stream Commands/Orders

The Read MDT Fields Alternate input command has been added. It is the same as the Read MDT Fields command except:
- The command is indicated by a X'82'
- Leading and embedded nulls within the field remain as nulls
The Read MDT Fields Immediate Alternate input command has been added. It is the same as the Read MDT Fields Alternate command except:
- The command is indicated by a X'83'
- The command is an immediate read command like Read Immediate; therefore, no control characters follow the command byte, field data is returned immediately, and the aid code is X'00'.
The Move Cursor order (MC) has been added (page 2-137). The MC order moves the cursor to the location specified by the two bytes following the order. Byte 1 gives the row address and byte 2 gives the column address. The MC order is useful when the cursor is to be moved without affecting the system IC address. The MC order is unaffected by the Write to Display control character values including the "Leave Cursor" flag (CC1 bit 1). If more than one MC or IC are found in the data stream, the cursor will move to the address specified in the last MC or IC.
Restrictions:
A parameter error will be posted when:
- There are fewer then two bytes following the order.
- The row address is zero or greater than the number of rows on the display screen.
- The column address is zero or greater than the number of columns on the display screen.
Format:
```
    Move Cursor Order  Byte 1        Byte 2
           X'14'       Row Address   Column Address
 
```
Results:
The address specified by the MC order is used to move the cursor when the Write to Display is completed.
The Transparent Data order (TD) has been added (page 2-137). The TD order is followed by two length bytes and transparent data. The transparent data is written to the display screen at the current display address; any values (Hex 00 to Hex FF) are allowed in the transparent data. All length values are valid as long as the end of the display screen is not overwritten.
Restrictions:
A parameter error will be posted when:
- There are fewer then two bytes following the order.
- There are fewer bytes in the data stream then specified in the length field.
- Attempting to write beyond the end of the display screen.
Format:
```
    TD Order   Bytes 1 and 2           Bytes 3 to ?
      X'10'    Length of transparent   Transparent data
               data (not counting
               length bytes)
 
```
Results:
The transparent data is written to the display.
The Query command is a new input command (page 2-5) and is used by the server to obtain information on the functional capabilities of the client 5250 display. When the client receives a Query command, the client sends a Query Reply describing its capabilities back to the server.
The Query command must follow an Escape ('04'X) and Write Structured Field command ('F3'X). The format of the Query command is as follows:
```
     Byte       Value        Description
    ======     =======   ========================
     0-1       X'0005'   Length of command
      2         X'D9'    Command Class
      3         X'70'    Command Type - Query
      4         X'00'    Flag Byte
       Bit 0:   B'0'     - Query Command
       Bit 1-7:          - Reserved (set to zero)
 
```
The format of the Query Reply is as follows:
```
     Byte   Value         Description
    ====== ========  ===================================
     0-1   X'0000'   Cursor Row/Column (set to zero)
      2    X'88'     Inbound Write Structured Field Aid
     3-4   X'003A'   Length of Query Reply
      5    X'D9'     Command Class
      6    X'70'     Command Type - Query
      7    X'80'     Flag Byte
       Bit 0:   B'1'  - Query Reply
       Bit 1-7:       - Reserved (set to zero)
     8-9            Controller Hardware Class
           X'0001'   - Local Twinax Controller
           X'0061'   - Local ASCII Controller
           X'0101'   - SDLC/X.21/X.25 Twinax Controller
                           (5394 emulating a 5294)
           X'0103'   - SDLC/X.21/X.25 Twinax Controller (5394)
           X'0200'   - PC DOS non-DBCS WSF
           X'0300'   - OS/2 non-DBCS WSF
           X'0400'   - PC DOS DBCS WSF
           X'0500'   - OS/2 DBCS WSF
           X'0600'   - Other WSF or any other 5250 Emulator
    10-12           Controller Code Level
           X'010300' - For example, Version 1 Rel 3.0
    13-28  X'00'    Reserved (set to zero)
     29             Device Type
           X'01'     - 5250 Display or 5250 Emulation
    30-33  C'cccc'  Device Type (e.g. 3180 for 3180 Mod 2)
    34-36  C'ccc'   Device Model (e.g. 002 for 3180 Mod 2)
     37             Keyboard ID
           X'02'     - Standard Keyboard
           X'82'     - G Keyboard
     38    X'00'    Extended Keyboard ID
     39    X'00'    Reserved
    40-43  X'xxxxxxxx' Display Serial Number
    44-45           Maximum number of input fields
           X'0100'   - Typically = 256 input fields
    46-48  X'00'    Reserved (set to zero)
    49-53           Controller/Display Capability
      Bit 0-1: B'00' - No Row 1/Col 1 support
               B'01' - Row 1/Col 1 support
      Bit 2:   B'0'  - No Read MDT Alternate Command support
               B'1'  - Read MDT Alternate Command support
      Bit 3:   B'0'  - Display does not have PA1/PA2 support
               B'1'  - Display does have PA1/PA2 support
      Bit 4:   B'0'  - Display does not have PA3 support
               B'1'  - Display does have PA3 support
      Bit 5:   B'0'  - Display does not have Cursor Select support
               B'1'  - Display does have Cursor Select support
      Bit 6:   B'0'  - Display does not have Move Cursor Order support
               B'1'  - Display does have Move Cursor Order support
      Bit 7:   B'0'  - No Read MDT Immediate Alt Command support
               B'1'  - Read MDT Immediate Alt Command support
    50
      Bit 0-3: B'0001' - 24 x 80 Screen Size
               B'0011' - Capable of 24 x 80 and 27 x 132
      Bit 4:   B'0'    - No light pen support
               B'1'    - Light pen support
      Bit 5:   B'0'    - No Mag Stripe Reader support
               B'1'    - Mag Stripe Reader support
      Bit 6-7: B'00'   - Mono display
               B'01'   - 5292/3179 style color, including color PCs
    51         X'00'   - Reserved
    52
      Bit 0-2: B'000'   - No Double Byte Character Set (DBCS)
                          capability
               B'001'   - Presentation screen DBCS capability only
      Bit 3-7: B'00000' - Reserved
    53
      Bit 0-2: B'000'   - No graphics capability
               B'001'   - 5292-2 style graphics
      Bit 3-7: B'00000' - Reserved
    54-60      X'00'    Reserved (set to zero)
 
```
References
1. IBM, "IBM 5250 Information Display System, Functions Reference Manual", SA21-9247-6, March 1987.
2. Postel, J. and J. Reynolds, "Telnet Protocol Specification", RFC 854, USC/Information Sciences Institute, May 1983.
3. Postel, J. and J. Reynolds, "Telnet Option Specifications", RFC 855, USC/Information Sciences Institute, May 1983.
4. Postel, J. and J. Reynolds, "Telnet Binary Transmission", RFC 856, USC/Information Sciences Institute, May 1983.
5. VanBokkeln, J., "Telnet Terminal-Type Option", RFC 1091, FTP Software, Inc., February 1989.
6. Postel, J. and J. Reynolds, "Telnet End of Record Option", RFC 885, USC/Information Sciences Institute, December 1983.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`AID_CLEAR`
`static int`	`AID_ENTER`
`static int`	`AID_F1`
`static int`	`AID_F10`
`static int`	`AID_F11`
`static int`	`AID_F12`
`static int`	`AID_F13`
`static int`	`AID_F14`
`static int`	`AID_F15`
`static int`	`AID_F16`
`static int`	`AID_F17`
`static int`	`AID_F18`
`static int`	`AID_F19`
`static int`	`AID_F2`
`static int`	`AID_F20`
`static int`	`AID_F21`
`static int`	`AID_F22`
`static int`	`AID_F23`
`static int`	`AID_F24`
`static int`	`AID_F3`
`static int`	`AID_F4`
`static int`	`AID_F5`
`static int`	`AID_F6`
`static int`	`AID_F7`
`static int`	`AID_F8`
`static int`	`AID_F9`
`static int`	`AID_FORWARD_EDGE_AUTO_ENTER`
`static int`	`AID_HELP`
`static int`	`AID_PA1`
`static int`	`AID_PA2`
`static int`	`AID_PA3`
`static int`	`AID_PGDN`
`static int`	`AID_PGUP`
`static int`	`AID_PRINT`
`static int`	`AID_RECORD_BACKSPACE`
`static int`	`CMD_CLEAR_FORMAT_TABLE`
`static int`	`CMD_CLEAR_UNIT`
`static int`	`CMD_CLEAR_UNIT_ALTERNATE`
`static int`	`CMD_ESCAPE`
`static int`	`CMD_READ_IMMEDIATE`
`static int`	`CMD_READ_INPUT_FIELDS`
`static int`	`CMD_READ_MDT_FIELDS`
`static int`	`CMD_READ_SCREEN`
`static int`	`CMD_RESTORE_SCREEN`
`static int`	`CMD_ROLL`
`static int`	`CMD_SAVE_SCREEN`
`static int`	`CMD_WRITE_ERROR_CODE`
`static int`	`CMD_WRITE_STRUCTURED_FIELD`
`static int`	`CMD_WRITE_TO_DISPLAY`
`static int`	`ORDER_EA`
`static int`	`ORDER_ESC`
`static int`	`ORDER_IC`
`static int`	`ORDER_MC`
`static int`	`ORDER_RA`
`static int`	`ORDER_SBA`
`static int`	`ORDER_SF`
`static int`	`ORDER_SOH`
`static int`	`ORDER_TD`
`static int`	`ORDER_WEA`

Constructor Summary

Constructors
Constructor and Description

DataStream5250(HostSession5250 hs, Display5250 d)
Creates the 5250 data stream.

Constructors
Constructor and Description
`DataStream5250(HostSession5250 hs, Display5250 d)` Creates the 5250 data stream.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`checkInputFields()` Checks all input fields for valid content.
`boolean`	`checkInputFields(boolean isEnterKey)` Checks all input fields for valid content.
`byte`	`convertCharToEBCDIC(char c)` Converts a single character to EBCDIC byte.
`char`	`convertEBCDICToChar(byte b)` Converts a single EBCDIC byte to character.
`static String`	`getAddressString(Display5250 display, int addr)` Gets the address string as "ADDR = addr, X/Y = x/y".
`String`	`getAddressString(int addr)` Gets the address string as "ADDR = addr, X/Y = x/y".
`String`	`getAddressString(int x, int y)` Gets the address string as "ADDR = addr, X/Y = x/y".
`Field`	`getFieldFromAddress(int addr)` Locates a field from an address.
`Field`	`getFieldFromAddress(int x, int y)` Locates a field from an address.
`FormatTable`	`getFormatTable()` Gets a reference to the format table.
`int`	`getHomeAddress()` Gets the cursor home address.
`String`	`getTerminalType()` Gets the terminal type.
`boolean`	`isAttribute(int ch)` Checks if a character is an attribute.
`boolean`	`isPrintable(int ch)` Checks if a character value is printable in EBCDIC.
`boolean`	`pageDown()` Performs the page down function.
`boolean`	`pageUp()` Performs the page up function.
`void`	`processData(short[] buf, int buflen)` Processes an incoming 5250 data stream packet.
`void`	`requestHelp(int errorCode)` Request error help description from the AS/400.
`boolean`	`sendAttention()` Sends the attention key.
`boolean`	`sendEnter()` Sends the Enter key.
`boolean`	`sendHelp(boolean inErrorState)` Sends the Help key.
`boolean`	`sendPA(int nn)` Sends a PA 1-3 key.
`boolean`	`sendPF(int nn)` Sends a PF 1-24 key.
`void`	`sendRecordBackspace()` Record Backspace Function.
`void`	`sendSystemRequest(String text)` Sends the system request string to the AS/400.
`boolean`	`sendTestRequest()` When the 5494 is enabled to access CSU or concurrent diagnostic information the 5494 operator and service personnel use the Test Request key sequence to access CSU and diagnostic routines.
`void`	`setTerminalType(String terminal)` The accepted terminal type.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - CMD_CLEAR_UNIT
```
public static final int CMD_CLEAR_UNIT
```
    See Also:
    
    Constant Field Values
  - CMD_CLEAR_UNIT_ALTERNATE
```
public static final int CMD_CLEAR_UNIT_ALTERNATE
```
    See Also:
    
    Constant Field Values
  - CMD_CLEAR_FORMAT_TABLE
```
public static final int CMD_CLEAR_FORMAT_TABLE
```
    See Also:
    
    Constant Field Values
  - CMD_WRITE_TO_DISPLAY
```
public static final int CMD_WRITE_TO_DISPLAY
```
    See Also:
    
    Constant Field Values
  - CMD_WRITE_ERROR_CODE
```
public static final int CMD_WRITE_ERROR_CODE
```
    See Also:
    
    Constant Field Values
  - CMD_READ_INPUT_FIELDS
```
public static final int CMD_READ_INPUT_FIELDS
```
    See Also:
    
    Constant Field Values
  - CMD_READ_MDT_FIELDS
```
public static final int CMD_READ_MDT_FIELDS
```
    See Also:
    
    Constant Field Values
  - CMD_READ_SCREEN
```
public static final int CMD_READ_SCREEN
```
    See Also:
    
    Constant Field Values
  - CMD_READ_IMMEDIATE
```
public static final int CMD_READ_IMMEDIATE
```
    See Also:
    
    Constant Field Values
  - CMD_SAVE_SCREEN
```
public static final int CMD_SAVE_SCREEN
```
    See Also:
    
    Constant Field Values
  - CMD_RESTORE_SCREEN
```
public static final int CMD_RESTORE_SCREEN
```
    See Also:
    
    Constant Field Values
  - CMD_ROLL
```
public static final int CMD_ROLL
```
    See Also:
    
    Constant Field Values
  - CMD_WRITE_STRUCTURED_FIELD
```
public static final int CMD_WRITE_STRUCTURED_FIELD
```
    See Also:
    
    Constant Field Values
  - CMD_ESCAPE
```
public static final int CMD_ESCAPE
```
    See Also:
    
    Constant Field Values
  - ORDER_SBA
```
public static final int ORDER_SBA
```
    See Also:
    
    Constant Field Values
  - ORDER_SF
```
public static final int ORDER_SF
```
    See Also:
    
    Constant Field Values
  - ORDER_SOH
```
public static final int ORDER_SOH
```
    See Also:
    
    Constant Field Values
  - ORDER_RA
```
public static final int ORDER_RA
```
    See Also:
    
    Constant Field Values
  - ORDER_EA
```
public static final int ORDER_EA
```
    See Also:
    
    Constant Field Values
  - ORDER_IC
```
public static final int ORDER_IC
```
    See Also:
    
    Constant Field Values
  - ORDER_MC
```
public static final int ORDER_MC
```
    See Also:
    
    Constant Field Values
  - ORDER_ESC
```
public static final int ORDER_ESC
```
    See Also:
    
    Constant Field Values
  - ORDER_WEA
```
public static final int ORDER_WEA
```
    See Also:
    
    Constant Field Values
  - ORDER_TD
```
public static final int ORDER_TD
```
    See Also:
    
    Constant Field Values
  - AID_F1
```
public static final int AID_F1
```
    See Also:
    
    Constant Field Values
  - AID_F2
```
public static final int AID_F2
```
    See Also:
    
    Constant Field Values
  - AID_F3
```
public static final int AID_F3
```
    See Also:
    
    Constant Field Values
  - AID_F4
```
public static final int AID_F4
```
    See Also:
    
    Constant Field Values
  - AID_F5
```
public static final int AID_F5
```
    See Also:
    
    Constant Field Values
  - AID_F6
```
public static final int AID_F6
```
    See Also:
    
    Constant Field Values
  - AID_F7
```
public static final int AID_F7
```
    See Also:
    
    Constant Field Values
  - AID_F8
```
public static final int AID_F8
```
    See Also:
    
    Constant Field Values
  - AID_F9
```
public static final int AID_F9
```
    See Also:
    
    Constant Field Values
  - AID_F10
```
public static final int AID_F10
```
    See Also:
    
    Constant Field Values
  - AID_F11
```
public static final int AID_F11
```
    See Also:
    
    Constant Field Values
  - AID_F12
```
public static final int AID_F12
```
    See Also:
    
    Constant Field Values
  - AID_F13
```
public static final int AID_F13
```
    See Also:
    
    Constant Field Values
  - AID_F14
```
public static final int AID_F14
```
    See Also:
    
    Constant Field Values
  - AID_F15
```
public static final int AID_F15
```
    See Also:
    
    Constant Field Values
  - AID_F16
```
public static final int AID_F16
```
    See Also:
    
    Constant Field Values
  - AID_F17
```
public static final int AID_F17
```
    See Also:
    
    Constant Field Values
  - AID_F18
```
public static final int AID_F18
```
    See Also:
    
    Constant Field Values
  - AID_F19
```
public static final int AID_F19
```
    See Also:
    
    Constant Field Values
  - AID_F20
```
public static final int AID_F20
```
    See Also:
    
    Constant Field Values
  - AID_F21
```
public static final int AID_F21
```
    See Also:
    
    Constant Field Values
  - AID_F22
```
public static final int AID_F22
```
    See Also:
    
    Constant Field Values
  - AID_F23
```
public static final int AID_F23
```
    See Also:
    
    Constant Field Values
  - AID_F24
```
public static final int AID_F24
```
    See Also:
    
    Constant Field Values
  - AID_CLEAR
```
public static final int AID_CLEAR
```
    See Also:
    
    Constant Field Values
  - AID_ENTER
```
public static final int AID_ENTER
```
    See Also:
    
    Constant Field Values
  - AID_HELP
```
public static final int AID_HELP
```
    See Also:
    
    Constant Field Values
  - AID_PGUP
```
public static final int AID_PGUP
```
    See Also:
    
    Constant Field Values
  - AID_PGDN
```
public static final int AID_PGDN
```
    See Also:
    
    Constant Field Values
  - AID_PRINT
```
public static final int AID_PRINT
```
    See Also:
    
    Constant Field Values
  - AID_RECORD_BACKSPACE
```
public static final int AID_RECORD_BACKSPACE
```
    See Also:
    
    Constant Field Values
  - AID_FORWARD_EDGE_AUTO_ENTER
```
public static final int AID_FORWARD_EDGE_AUTO_ENTER
```
    See Also:
    
    Constant Field Values
  - AID_PA1
```
public static final int AID_PA1
```
    See Also:
    
    Constant Field Values
  - AID_PA2
```
public static final int AID_PA2
```
    See Also:
    
    Constant Field Values
  - AID_PA3
```
public static final int AID_PA3
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - DataStream5250
```
public DataStream5250(HostSession5250 hs,
                      Display5250 d)
```
    Creates the 5250 data stream.
- Method Detail
  - setTerminalType
```
public void setTerminalType(String terminal)
```
    The accepted terminal type.
  - getTerminalType
```
public String getTerminalType()
```
    Gets the terminal type.
  - requestHelp
```
public void requestHelp(int errorCode)
```
    Request error help description from the AS/400.
  - sendSystemRequest
```
public void sendSystemRequest(String text)
```
    Sends the system request string to the AS/400. Note that the string cannot contain null characters, they must be blanks.
  - sendAttention
```
public boolean sendAttention()
                      throws IOException
```
    Sends the attention key.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - sendTestRequest
```
public boolean sendTestRequest()
                        throws IOException
```
    When the 5494 is enabled to access CSU or concurrent diagnostic information the 5494 operator and service personnel use the Test Request key sequence to access CSU and diagnostic routines. The 5494 does not send information or AID codes to the AS/400 system when an operator enters this key sequence.
    For specific Test Request key sequences, refer to the IBM 5494 Remote Control Unit User's Guide.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - getFieldFromAddress
```
public Field getFieldFromAddress(int addr)
```
    Locates a field from an address.
    
    Returns:
    
    null if no such field is found.
  - getFieldFromAddress
```
public Field getFieldFromAddress(int x,
                                 int y)
```
    Locates a field from an address.
    
    Returns:
    
    null if no such field is found.
  - sendPF
```
public boolean sendPF(int nn)
               throws IOException
```
    Sends a PF 1-24 key.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - sendPA
```
public boolean sendPA(int nn)
               throws IOException
```
    Sends a PA 1-3 key.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - sendEnter
```
public boolean sendEnter()
                  throws IOException
```
    Sends the Enter key.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - pageUp
```
public boolean pageUp()
               throws IOException
```
    Performs the page up function.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - pageDown
```
public boolean pageDown()
                 throws IOException
```
    Performs the page down function.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - sendRecordBackspace
```
public void sendRecordBackspace()
                         throws IOException
```
    Record Backspace Function.
    When the Home key is pressed with the cursor already at the home position, a record backspace is requested; the keyboard is locked and the AID code (X'F8') and cursor address are sent to the AS/400 system. The AS/400 system should respond by repeating the writing of the previous record to the display.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - sendHelp
```
public boolean sendHelp(boolean inErrorState)
                 throws IOException
```
    Sends the Help key.
    If the display is not in an operator-error state and the workstation operator presses the Help key, the workstation issues an X'F3' AID byte to the AS/400 system. If, however, the workstation operator presses the Help key after pressing the Cmd key or the Sys Req key, an error results.
    
    Throws:
    
    IOException - if a data stream problem occurs.
  - processData
```
public void processData(short[] buf,
                        int buflen)
```
    Processes an incoming 5250 data stream packet.
    Data Stream Format:
    The actual data stream that is exchanged between the client and server is composed of a header followed by the 5250 work station data stream. For information about the 5250 work station data stream refer to the IBM 5250 Information Display System, Functions Reference Manual (SA21-9247). The header which prefixes the 5250 data stream was originally designed for the 5250 Display Station Pass-Through (DSPT) application. 5250 DSPT is an application similar to Telnet which runs on the IBM AS/400, System/36, and System/38 over an SNA network. This header is designed to be variable in length and is composed of two parts. The first, fixed part is always 6 bytes long and has the following format:
```
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |     Logical Record Length     |       Record Type             |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |        Reserved               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
```
    Logical Record Length: 16 bits
    This field indicates the length, in bytes, of this logical record including the header length. The length is specified with the most significant byte first. For example, a length of 36 (decimal) would be specified as '0024'X.
    Record Type: 16 bits
    This field indicates the SNA record type. It should always be set to '12A0'X to indicate the General Data Stream (GDS) record type.
    Reserved: 16 bits
    This field is currently not used.
    The second part of the header is designed to be variable in length. The length of this variable part is specified in the first byte. Currently this portion of the header will always be 4 bytes long and has the following format:
```
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |               |E|A| | | |S|T|H|               |               |
  | Var Hdr Len   |R|T| | | |R|R|L|               |    Opcode     |
  |               |R|N| | | |Q|Q|P|               |               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
```
    Var Hdr Len: 8 bits
    The length, in bytes, of the variable portion of the header. Currently this is always '04'X.
    Flags: 16 bits
```
    Bit 0:      ERR     This bit is set to indicate a data stream
                        output error. The negative response code
                        is sent as data following the opcode field.

    Bit 1:      ATN     This bit is set to indicate that the 5250
                        attention key was pressed.

    Bits 2-4:   *       These bits are reserved (set to zero).

    Bit 5:      SRQ     This bit is set to indicate that the 5250
                        System Request key was pressed.

    Bit 6:      TRQ     This bit is set to indicate that the 5250
                        Test Request key was pressed.

    Bit 7:      HLP     This bit is set to indicate the Help in
                        Error State function. The error code is
                        sent as data following the header and is
                        a four digit packed decimal number.  For
                        example, an error code of '0005'X indicates
                        the operator attempted to type in an area of
                        the display that is not enabled for input.

    Bits 8-15:  *       These bits are reserved (set to zero).
 
```
    Opcode: 8 bits
    This field contains the operation code. It is set to indicate the type of operation requested by the sender. The following are the valid values:
```
   '00'X:  No Operation
   '01'X:  Invite Operation
   '02'X:  Output Only
   '03'X:  Put/Get Operation
   '04'X:  Save Screen Operation
   '05'X:  Restore Screen Operation
   '06'X:  Read Immediate Operation
   '07'X:  Reserved
   '08'X:  Read Screen Operation
   '09'X:  Reserved
   '0A'X:  Cancel Invite Operation
   '0B'X:  Turn On Message Light
   '0C'X:  Turn Off Message Light
 
```
    The actual 5250 work station data stream will immediately follow the opcode field in the header and will be terminated by the IAC EOR pair (not included in the buffer).
    For some operations the header will be immediately followed by an IAC EOR without any 5250 work station data stream in between.
    For example, the following request to turn on the message light could be sent by the server:
```
     000A 12A0 0000 0400 000B FFEF
     |    |    |    | |    |  |
     |    |    |    | |    |  End Of Record marker
     |    |    |    | |    |
     |    |    |    | |    Opcode = Turn On Message Light ('0B'X)
     |    |    |    | |
     |    |    |    | Flags = '0000'X
     |    |    |    |
     |    |    |    Variable Header Length = '04'X
     |    |    |
     |    |    Reserved - Set to '0000'X
     |    |
     |    Record Type = General Data Stream ('12A0'X)
     |
     Logical Record Length = '000A'X for this record
 
```
    In this example the requested operation is indicated by the opcode and there is no associated work station data stream.
  - isPrintable
```
public boolean isPrintable(int ch)
```
    Checks if a character value is printable in EBCDIC. Data characters can be placed in the data stream following the WTD control characters. The data characters are generally greater than or equal to X'20' and less than or equal to X'FE'. X'FF' is not a valid data character. The null character (X'00'), duplicate character (X'1C'), field mark character (X'1E'), ideographic shift-in (X'OE'), and ideographic shift-out (X'0F') are valid data characters.
  - convertEBCDICToChar
```
public char convertEBCDICToChar(byte b)
```
    Converts a single EBCDIC byte to character.
  - convertCharToEBCDIC
```
public byte convertCharToEBCDIC(char c)
```
    Converts a single character to EBCDIC byte.
  - isAttribute
```
public boolean isAttribute(int ch)
```
    Checks if a character is an attribute.
  - getFormatTable
```
public FormatTable getFormatTable()
```
    Gets a reference to the format table.
  - checkInputFields
```
public boolean checkInputFields()
```
    Checks all input fields for valid content. If the master MDT bit is not set, this check is not performed.
  - checkInputFields
```
public boolean checkInputFields(boolean isEnterKey)
```
    Checks all input fields for valid content. If the master MDT bit is not set, this check is not performed.
  - getHomeAddress
```
public int getHomeAddress()
```
    Gets the cursor home address.
  - getAddressString
```
public String getAddressString(int addr)
```
    Gets the address string as "ADDR = addr, X/Y = x/y".
  - getAddressString
```
public static String getAddressString(Display5250 display,
                                      int addr)
```
    Gets the address string as "ADDR = addr, X/Y = x/y".
  - getAddressString
```
public String getAddressString(int x,
                               int y)
```
    Gets the address string as "ADDR = addr, X/Y = x/y".

Class DataStream5250

5250 Data Stream Enhancements

Errors or Inconsistencies in SA21-9247-6

Enhancements to Existing 5250 Data Stream Commands/Orders

New 5250 Data Stream Commands/Orders

References

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CMD_CLEAR_UNIT

CMD_CLEAR_UNIT_ALTERNATE

CMD_CLEAR_FORMAT_TABLE

CMD_WRITE_TO_DISPLAY

CMD_WRITE_ERROR_CODE

CMD_READ_INPUT_FIELDS

CMD_READ_MDT_FIELDS

CMD_READ_SCREEN

CMD_READ_IMMEDIATE

CMD_SAVE_SCREEN

CMD_RESTORE_SCREEN

CMD_ROLL

CMD_WRITE_STRUCTURED_FIELD

CMD_ESCAPE

ORDER_SBA

ORDER_SF

ORDER_SOH

ORDER_RA

ORDER_EA

ORDER_IC

ORDER_MC

ORDER_ESC

ORDER_WEA

ORDER_TD

AID_F1

AID_F2

AID_F3

AID_F4

AID_F5

AID_F6

AID_F7

AID_F8

AID_F9

AID_F10

AID_F11

AID_F12

AID_F13

AID_F14

AID_F15

AID_F16

AID_F17

AID_F18

AID_F19

AID_F20

AID_F21

AID_F22

AID_F23

AID_F24

AID_CLEAR

AID_ENTER

AID_HELP

AID_PGUP

AID_PGDN

AID_PRINT

AID_RECORD_BACKSPACE

AID_FORWARD_EDGE_AUTO_ENTER

AID_PA1

AID_PA2

AID_PA3

Constructor Detail

DataStream5250

Method Detail

setTerminalType

getTerminalType

requestHelp

sendSystemRequest

sendAttention

sendTestRequest

getFieldFromAddress