Update Travis configuration (#643)

Signed-off-by: Wouter Born <github@maindrain.net>

.travis.yml

@@ -1,27 +1,54 @@
 sudo: required
-dist: trusty
+dist: xenial
 
 language: java
-jdk: oraclejdk8
+
+jdk:
+  - openjdk8
+  - openjdk11
 
 cache:
   directories:
   - $HOME/.m2
   - $HOME/.p2
-  - extensions/ui/org.eclipse.smarthome.ui.paper/npm_cache
-
-before_install: echo "MAVEN_OPTS='-Xms1g -Xmx2g -XX:PermSize=512m -XX:MaxPermSize=1g'" > ~/.mavenrc
-
-#$ mvn install -DskipTests=true -Dmaven.javadoc.skip=true -B -V
-#$ mvn test -B
 
+before_install:
+  - echo "MAVEN_OPTS='-Xms1g -Xmx2g'" > ~/.mavenrc
 install:
-  - echo 'mvn clean verify -B -V -Dspotbugs.skip=true 1> .build.stdout 2> .build.stderr' > .build.sh
-  - chmod 0755 .build.sh
-script:
-  - travis_wait 60 ./.build.sh
+  - |
+    function extra_maven_opts() {
+        if [ "$TRAVIS_JDK_VERSION" != "openjdk8" ]; then echo "-Denforcer.skip=true"; fi;
+    }
+    function prevent_timeout() {
+        local i=0
+        while [ -e /proc/$1 ]; do
+            # print zero width char every 3 minutes while building
+            if [ "$i" -eq "180" ]; then printf %b '\u200b'; i=0; else i=$((i+1)); fi
+            sleep 1
+        done
+    }
+    function print_reactor_summary() {
+        sed -ne '/\[INFO\] Reactor Summary:/,$ p' "$1" | sed 's/\[INFO\] //'
+    }
+    function mvnp() {
+        set -o pipefail # exit build with error when pipes fail
+        local command=(mvn $@)
+        exec "${command[@]}" 2>&1 | # execute, redirect stderr to stdout
+            tee .build.log | # write output to log
+            stdbuf -oL grep -E '^\[INFO\] Building .+ \[.+\]$' | # filter progress
+            sed -uE 's/^\[INFO\] Building (.*[^ ])[ ]+\[([0-9]+\/[0-9]+)\]$/\2| \1/' | # prefix project name with progress
+            sed -e :a -e 's/^.\{1,6\}|/ &/;ta' & # right align progress with padding
+        local pid=$!
+        prevent_timeout $pid &
+        wait $pid
+    }
 after_success:
-  - tail -n  200 .build.stdout
+  - print_reactor_summary .build.log
 after_failure:
-  - tail -n  300 .build.stderr
-  - tail -n 2000 .build.stdout
+  - tail -n 2000 .build.log
+env: # required for allowing failures
+matrix:
+  allow_failures:
+    - jdk: openjdk11
+script:
+  - mvnp clean verify -B -DskipChecks $(extra_maven_opts)