org.apache.derby.impl.drda
Class DRDAString

java.lang.Object
  org.apache.derby.impl.drda.DRDAString

final class DRDAString
extends java.lang.Object

This class provides functionality for reusing buffers and strings when parsing DRDA packets. A byte array representing a string is stored internally. When the string is requested as a String object, the byte array is converted to a string, and the string is cached to avoid unnecessary conversion later.

Field Summary

private byte[]	buffer Buffer representing the string.
private java.lang.String	cachedString The previously generated string.
private boolean	modified True if the contents were modified in the previous call to setBytes.
private DDMWriter	writer Keep the DDMWriter as it contains the current CCSID manager being used

Constructor Summary

DRDAString(DDMWriter w)
Create a new DRDAString instance.

Method Summary

private boolean	equalTo(byte[] buf, int offset, int size) Check whether the internal buffer contains the same data as another byte buffer.
byte[]	getBytes() Return the internal byte array.
int	length() Return the length in bytes of the internal string representation.
void	setBytes(byte[] src, int offset, int size) Modify the internal byte buffer.
java.lang.String	toString() Convert the internal byte array to a string.
boolean	wasModified() Check whether the contents of the DRDAString were modified in the previous call to setBytes().

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

buffer

private byte[] buffer

Buffer representing the string.

writer

private final DDMWriter writer

Keep the DDMWriter as it contains the current CCSID manager being used

modified

private boolean modified

True if the contents were modified in the previous call to setBytes.

cachedString

private java.lang.String cachedString

The previously generated string.

Constructor Detail

DRDAString

DRDAString(DDMWriter w)

Create a new DRDAString instance.

Parameters:

w - a DDMWriter which holds current CCSidManager and which encoding is used

Method Detail

equalTo

private boolean equalTo(byte[] buf,
                        int offset,
                        int size)

Check whether the internal buffer contains the same data as another byte buffer.

Parameters:

buf - a byte array

offset - start position in the byte array

size - how many bytes to read from the byte array

Returns:

true if the internal buffer contains the same data as the specified byte array

setBytes

public void setBytes(byte[] src,
                     int offset,
                     int size)

Modify the internal byte buffer. If the new data is equal to the old data, the cached values are not cleared.

Parameters:

src - the new bytes

offset - start offset

size - number of bytes to use

wasModified

public boolean wasModified()

Check whether the contents of the DRDAString were modified in the previous call to setBytes().

Returns:

true if the contents were modified

toString

public java.lang.String toString()

Convert the internal byte array to a string. The string value is cached.

Overrides:

toString in class java.lang.Object

Returns:

a String value

length

public int length()

Return the length in bytes of the internal string representation.

Returns:

length of internal representation

getBytes

public byte[] getBytes()

Return the internal byte array. The returned array should not be modified, as it is used internally in DRDAString. The value of the array might be modified by subsequent calls to DRDAString.setBytes().

Returns:

internal buffer