For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:search/openSUSE_Tumbleweed/server:search.repo
zypper refresh
zypper install clucene-core
For openSUSE Leap 15.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:search/openSUSE_Leap_15.1/server:search.repo
zypper refresh
zypper install clucene-core
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:search/openSUSE_Factory/server:search.repo
zypper refresh
zypper install clucene-core
For openSUSE 13.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:search/openSUSE_13.1/server:search.repo
zypper refresh
zypper install clucene-core