bigtop-detect-javahome

#!/usr/bin/env bash
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# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# Override JAVA_HOME in the file below if you want to disable
# automatic JAVA_HOME detection
BIGTOP_DEFAULTS_DIR=${BIGTOP_DEFAULTS_DIR-/etc/default}
[ -n "${BIGTOP_DEFAULTS_DIR}" -a -r ${BIGTOP_DEFAULTS_DIR}/bigtop-utils ] && . ${BIGTOP_DEFAULTS_DIR}/bigtop-utils

JAVA8_HOME_CANDIDATES=(
    '/usr/java/jdk1.8'
    '/usr/java/jre1.8'
    '/usr/lib/jvm/j2sdk1.8-oracle'
    '/usr/lib/jvm/j2sdk1.8-oracle/jre'
    '/usr/lib/jvm/java-8-oracle'
    '/usr/lib/jdk8-latest'
    '/usr/lib/jvm/java-1.8.0'
    '/usr/lib/jvm/java-1.8.0-oracle'
)

OPENJAVA8_HOME_CANDIDATES=(
    '/usr/lib/jvm/java-1.8.0-openjdk-amd64'
    '/usr/lib/jvm/java-1.8.0-openjdk-ppc64el'
    '/usr/lib/jvm/java-1.8.0-openjdk'
    '/usr/lib64/jvm/java-1.8.0-openjdk-1.8.0'
    '/usr/lib/jvm/temurin-8-jdk'
)

MISCJAVA_HOME_CANDIDATES=(
    '/Library/Java/Home'
    '/usr/java/default'
    '/usr/lib/jvm/java'
    '/usr/lib/jvm/jre'
    '/usr/lib/jvm/default-java'
    '/usr/lib/jvm/java-openjdk'
    '/usr/lib/jvm/jre-openjdk'
    '/usr/lib/jvm/java-oracle'
)

case ${BIGTOP_JAVA_MAJOR} in
  6|7) echo "Java ${BIGTOP_JAVA_MAJOR} is no longer supported. Please upgrade"
     exit 1
     ;;
  8) JAVA_HOME_CANDIDATES=(${JAVA8_HOME_CANDIDATES[@]} ${OPENJAVA8_HOME_CANDIDATES[@]})
     ;;
  *) JAVA_HOME_CANDIDATES=(${JAVA8_HOME_CANDIDATES[@]}
                           ${MISCJAVA_HOME_CANDIDATES[@]}
                           ${OPENJAVA8_HOME_CANDIDATES[@]})
     ;;
esac

# attempt to find java
if [ -z "${JAVA_HOME}" ]; then
  for candidate_regex in ${JAVA_HOME_CANDIDATES[@]} ; do
      for candidate in `ls -rvd ${candidate_regex}* 2>/dev/null`; do
        if [ -e ${candidate}/bin/java ]; then
          export JAVA_HOME=${candidate}
          break 2
        fi
      done
  done
fi