enhance release script to check for required dependencies (ant, maven, mvn...)

git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/branches/pmd/4.2.x@7236 51baf565-9d33-0410-a72c-fc3788e3496d

pmd/etc/generate_release.sh

@@ -5,6 +5,17 @@ usage() {
     echo "this scripts requires the release version number"
 }
 
+check_dependency() {
+    local binary="${1}"
+
+    which "${binary}" > /dev/null
+    local status="${?}"
+    if [ ${status} -ne 0 ]; then
+        echo "missing dependency:${binary}"
+        exit ${status}
+    fi
+}
+
 version="${1}"
 
 if [ -z ${version} ]; then
@@ -12,6 +23,10 @@ if [ -z ${version} ]; then
     exit 1
 fi
 
+check_dependency ant
+check_dependency maven
+check_dependency mvn
+
 echo "building release version ${version}"
 
 pmd_top_dir="$(mktemp -d)"