JesVsam (IBM JZOS Toolkit API)

java.lang.Object
- com.ibm.jzos.JesVsam

```
public class JesVsam
extends java.lang.Object
```
This class is for internal use only.
Used by MvsJobSubmitter to submit jobs to the internal reader.
Note: I/O performed using these classes must be performed on a single thread.

Since:

2.4.0

Field Summary

Fields
Modifier and Type Field and Description

static int MODE_BINARY

static int MODE_RECORD

static int MODE_TEXT

Fields
Modifier and Type	Field and Description
`static int`	`MODE_BINARY`
`static int`	`MODE_RECORD`
`static int`	`MODE_TEXT`

Constructor Summary

Constructors
Constructor and Description
`JesVsam(java.lang.String ddname, boolean isWrite)` Create a new instance suitable for handling I/O for the supplied ddname.
`JesVsam(java.lang.String ddname, boolean isWrite, boolean isFixedLength, int bufferSize)` Create a new instance suitable for handling I/O for the supplied ddname.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`advance(int numrecs, int buflen)` Advance the underlying VSAM file by numrecs from the current position.
`byte[]`	`close()` Flush any buffered records (if write mode) and close the underlying VSAM file.
`byte[]`	`closeWithoutFlush()` Close the underlying VSAM file.
`void`	`flush()` Flushes any pending data in the record buffer into VSAM PUTs.
`java.lang.String`	`getDDName()` Answers the DD name used to open the underlying VSAM file.
`int`	`getLrecl()` Answer the LRECL, which is the maximum record length for variable length files.
`long`	`getRbar()` Answer the RBA of the last record (in the last buffer) read or written.
`boolean`	`isOpen()` Answer true if the file is open, false otherwise.
`boolean`	`isWrite()`
`static void`	`logDiagnostic(int level, java.lang.String msg)` Send a message to the native libraries log, which goes to the Language Environment messages file, which is usually stderr or DD //SYSOUT.
`void`	`point(long rba)` Point to a given RBA before reading.
`int`	`readBuffer(byte[] buffer, int mode)` Read one or more records into the given buffer
`long`	`readBuffer(byte[] buffer, int mode, int maxRecords)` Read one or more records into the given buffer
`static void`	`setLoggingLevel(int level)` Sets the logging level for the Toolkit native code.
`void`	`setLrecl(int lrecl)` Set the LRECL, which is used to control the length of records written (in write mode).
`void`	`write(byte[] record)` Write the supplied bytes as the next sequential record.
`void`	`write(byte[] record, int offset, int len)` Write the supplied bytes, starting at offset for len, as the next sequential record.

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

- Field Detail
  - MODE_RECORD
```
public static final int MODE_RECORD
```
    See Also:
    
    Constant Field Values
  - MODE_BINARY
```
public static final int MODE_BINARY
```
    See Also:
    
    Constant Field Values
  - MODE_TEXT
```
public static final int MODE_TEXT
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - JesVsam
```
public JesVsam(java.lang.String ddname,
               boolean isWrite)
        throws java.io.IOException
```
    Create a new instance suitable for handling I/O for the supplied ddname.
    
    Parameters:
    
    ddname - the DD
    
    isWrite - if true, the DD is opened for write access, read otherwise
    
    Throws:
    
    java.io.IOException - if a native I/O error occurs
  - JesVsam
```
public JesVsam(java.lang.String ddname,
               boolean isWrite,
               boolean isFixedLength,
               int bufferSize)
        throws JesVsamException
```
    Create a new instance suitable for handling I/O for the supplied ddname.
    
    Parameters:
    
    ddname - the DD
    
    isWrite - if true, the DD is opened for write access, read otherwise
    
    isFixedLength - if true, fixed length records are used (only used for write mode)
    
    bufferSize - the size of record buffer (only used for write mode)
    
    Throws:
    
    java.io.IOException - if a native I/O error occurs
    
    JesVsamException
- Method Detail
  - close
```
public byte[] close()
             throws JesVsamException
```
    Flush any buffered records (if write mode) and close the underlying VSAM file. If successful, returns an 8-byte byte array containing the final RBAR (after an ENDREQ is issued for the file).
    
    Throws:
    
    JesVsamException
  - closeWithoutFlush
```
public byte[] closeWithoutFlush()
                         throws JesVsamException
```
    Close the underlying VSAM file. If successful, returns an 8-byte byte array containing the final RBAR (after an ENDREQ is issued for the file).
    
    Throws:
    
    JesVsamException
  - isOpen
```
public boolean isOpen()
```
    Answer true if the file is open, false otherwise.
  - flush
```
public void flush()
           throws JesVsamException
```
    Flushes any pending data in the record buffer into VSAM PUTs.
    
    Throws:
    
    java.io.IOException
    
    JesVsamException
  - getLrecl
```
public int getLrecl()
```
    Answer the LRECL, which is the maximum record length for variable length files.
    Note: This value may not be accurate for JES3 jobs.
  - setLrecl
```
public void setLrecl(int lrecl)
```
    Set the LRECL, which is used to control the length of records written (in write mode).
  - getRbar
```
public long getRbar()
             throws JesVsamException
```
    Answer the RBA of the last record (in the last buffer) read or written.
    
    Returns:
    
    long the 8 byte RBA address
    
    Throws:
    
    JesVsamException
  - getDDName
```
public java.lang.String getDDName()
```
    Answers the DD name used to open the underlying VSAM file.
    
    Returns:
    
    String ddname
  - readBuffer
```
public int readBuffer(byte[] buffer,
                      int mode)
               throws JesVsamException
```
    Read one or more records into the given buffer
    
    Parameters:
    
    buffer - which is to contain the records, formatted according to the given mode. MODE_RECORD: each preceded by a 4 byte big-endian length; MODE_TEXT: each record has trailing spaces trimmed and is terminated by a newline (x'15); MODE:BIN: no record separators are present.
    
    Returns:
    
    int -1 if EOF (no more records), otherwise the number of bytes used in the buffer (low-order 32-bits)
    
    Throws:
    
    JesVsamException
  - readBuffer
```
public long readBuffer(byte[] buffer,
                       int mode,
                       int maxRecords)
                throws JesVsamException
```
    Read one or more records into the given buffer
    
    Parameters:
    
    buffer - which is to contain the records, formatted according to the given mode. MODE_RECORD: each preceded by a 4 byte big-endian length; MODE_TEXT: each record has trailing spaces trimmed and is terminated by a newline (x'15); MODE:BIN: no record separators are present.
    
    maxRecords - the maximum number of records to read.
    
    Returns:
    
    long -1 if EOF (no more records), otherwise a combination of the number of records read (high-order 32 bits) + the number of bytes used in the buffer (low-order 32-bits); both are positive integers.
    
    Throws:
    
    JesVsamException
  - point
```
public void point(long rba)
           throws JesVsamException
```
    Point to a given RBA before reading. Forces a flush of any previous read or write buffer.
    
    Throws:
    
    JesVsamException
  - advance
```
public int advance(int numrecs,
                   int buflen)
            throws JesVsamException
```
    Advance the underlying VSAM file by numrecs from the current position.
    
    Parameters:
    
    numrecs - the number of records to advance
    
    buflen - the native buffer size to use
    
    Returns:
    
    the number of records advanced. If this number is less than numrecs, EOF was reached before the numrecs were advanced.
    
    Throws:
    
    JesVsamException
  - write
```
public void write(byte[] record)
           throws JesVsamException
```
    Write the supplied bytes as the next sequential record. Will fail if isWrite() is false.
    
    Parameters:
    
    record - the bytes to write. The length of the byte array must be less than or equal to the maximum LRECL of the underlying dataset.
    
    Throws:
    
    java.io.IOException - if a native I/O error occurs
    
    JesVsamException
  - write
```
public void write(byte[] record,
                  int offset,
                  int len)
           throws JesVsamException
```
    Write the supplied bytes, starting at offset for len, as the next sequential record. Will fail if isWrite() is false.
    
    Parameters:
    
    record - the bytes to write.
    
    offset - the offset of the first byte in the supplied byte array to write.
    
    len - the number of bytes to write. Must be less than or equal to the maximum LRECL of the underlying dataset.
    
    Throws:
    
    java.io.IOException - if a native I/O error occurs
    
    JesVsamException
  - isWrite
```
public boolean isWrite()
```
    Returns:
    
    true if opened in write mode, false if read mode.
  - logDiagnostic
```
public static void logDiagnostic(int level,
                                 java.lang.String msg)
```
    Send a message to the native libraries log, which goes to the Language Environment messages file, which is usually stderr or DD //SYSOUT.
    
    Parameters:
    
    level - one of the LOG_XXX constants defined above
    
    msg - the message text
  - setLoggingLevel
```
public static void setLoggingLevel(int level)
```
    Sets the logging level for the Toolkit native code. This method can be used to enable debugging output from the toolkit native library.
    Alternatively, a system property can be used to set the toolkit logging level. This property has the form: -Djzos.logging={E|W|N|I|D|T}
    
    Parameters:
    
    level - one of the LOG_XXX constants defined above
    
    See Also:
    
    logDiagnostic(int, String)

Methods inherited from class java.lang.Object

MODE_RECORD

MODE_BINARY

MODE_TEXT

JesVsam

JesVsam

close

closeWithoutFlush

isOpen

flush

getLrecl

setLrecl

getRbar

getDDName

readBuffer

readBuffer

point

advance

write

write

isWrite

logDiagnostic

setLoggingLevel