package-version=${version;===;${Bundle-Version}}

commons-logging-version=${version;===;1.2}
log4j-api-version=${version;===;2.6}
log4j-version=${version;===;1.2}
slf4j-api-version=${version;===;1.7}

commons-logging-version-range=${range;[===,+);${commons-logging-version}}
log4j-api-version-range=${range;[===,+);${log4j-api-version}}
log4j-version-range=${range;[===,+);${log4j-version}}
slf4j-api-version-range=${range;[===,+);${slf4j-api-version}}

Export-Package: \
 !about.html,!about_files, \
 *.internal.*;x-internal:=true;version="${package-version}", \
 *.implementation.*;x-internal:=true;version="${package-version}", \
 *.impl.*;x-internal:=true;version="${package-version}", \
 *;version="${package-version}"

Import-Package: \
 org.apache.commons.logging;version="${commons-logging-version-range}";resolution:=optional, \
 org.apache.log4j;version="${log4j-version-range}";resolution:=optional, \
 org.apache.logging.log4j.*;version="${log4j-api-version-range}";resolution:=optional, \
 org.slf4j.*;version="${slf4j-api-version-range}";resolution:=optional, \
 *;resolution:=optional