sed: toupper a character on a location - sed

Question

This
sed "s/public \(.*\) get\(.*\)()/\1 \2/g"
will transfor this
public class ChallengeTO extends AbstractTransferObject {
public AuthAlgorithm getAlgorithm();
public long getCode();
public int getIteration();
public String getPublicKey();
public String getSelt();
};
into this
public class ChallengeTO extends AbstractTransferObject {
AuthAlgorithm Algorithm;
long Code;
int Iteration;
String PublicKey;
String Selt;
};
I want to change Algorithm to algorithm, PublicKey to publicKey and so on. How can I transform the first character of the second segment (\2) to lower case?
UPDATE
sed "s/public \(.*\) get\([A-Z]\)\(.*\)()/\1 \2\3/g" selects "my letter" as \2, but if I place a \L before it it transforms too much (including \3)

Answer 1

here's an awk solution
awk '
$1=="public" && $3~/^get/ {
sub(/^get/,"",$3)
$3=tolower( substr($3,1,1) ) substr($3,2)
$0="\t"$2" "$3
}1' file
output
$ cat file
public class ChallengeTO extends AbstractTransferObject {
public AuthAlgorithm getAlgorithm();
public long getCode();
public int getIteration();
public String getPublicKey();
public String getSelt();
};
$ ./shell.sh
public class ChallengeTO extends AbstractTransferObject {
AuthAlgorithm algorithm();
long code();
int iteration();
String publicKey();
String selt();
};
if you still prefer sed, here's a modification to your version, adding \l
$ sed 's/public \(.*\) get\([A-Z]\)\(.*\)()/\1 \l\2\3/g' file
public class ChallengeTO extends AbstractTransferObject {
AuthAlgorithm algorithm;
long code;
int iteration;
String publicKey;
String selt;
};

Answer 2

This is nearly identical to upper- to lower-case using sed.
EDIT: The question/answer there uses the \L GNU sed extension. The conversion begun by \L can be turned off by \E, so if you tease out "your letter" into \2, you can put a \L before it and a \E immediately after it.
See the GNU sed documentation for more information.
If you don't have GNU extensions, you can do this with two separate sed commands. You can use the y command to change a character that matches one of a source character into a corresponding destination character. This is similar to the Unix utility tr.