Feature/optional jcache

[benfortuna]

No description provided.

[codecov]

Codecov Report

Merging #198 into develop will increase coverage by 0.19%.
The diff coverage is 75%.

@@              Coverage Diff              @@
##             develop     #198      +/-   ##
=============================================
+ Coverage      65.13%   65.33%   +0.19%     
- Complexity      1794     1823      +29     
=============================================
  Files            282      285       +3     
  Lines           7990     8030      +40     
  Branches        1149     1150       +1     
=============================================
+ Hits            5204     5246      +42     
+ Misses          2388     2385       -3     
- Partials         398      399       +1

Impacted Files	Coverage Δ	Complexity Δ
.../fortuna/ical4j/model/TimeZoneRegistryFactory.java	100% <100%> (+37.5%)	3 <1> (ø)	⬇️
...n/java/net/fortuna/ical4j/util/DecoderFactory.java	100% <100%> (+37.5%)	3 <1> (ø)	⬇️
...va/net/fortuna/ical4j/util/CompatibilityHints.java	87.5% <100%> (ø)	5 <0> (ø)	⬇️
...net/fortuna/ical4j/data/CalendarParserFactory.java	100% <100%> (+22.22%)	3 <1> (ø)	⬇️
src/main/java/net/fortuna/ical4j/model/Recur.java	78.26% <100%> (+0.25%)	150 <1> (ø)	⬇️
...c/main/java/net/fortuna/ical4j/util/TimeZones.java	70% <100%> (ø)	6 <2> (ø)	⬇️
...n/java/net/fortuna/ical4j/util/EncoderFactory.java	100% <100%> (+37.5%)	3 <1> (ø)	⬇️
.../java/net/fortuna/ical4j/model/TimeZoneLoader.java	71.61% <38.46%> (+0.52%)	21 <2> (ø)	⬇️
...ain/java/net/fortuna/ical4j/util/Configurator.java	57.14% <52.17%> (-12.09%)	8 <5> (+5)
...java/net/fortuna/ical4j/util/MapTimeZoneCache.java	83.33% <83.33%> (ø)	5 <5> (?)
... and 6 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7416495...3535a5d. Read the comment docs.

[rfc2822]

Thank you!

Without an ical4j.properties (I have configured it within a static code block), I get a NullPointerException because CONFIG seems to be null:

java.lang.ExceptionInInitializerError
    at net.fortuna.ical4j.util.Configurator.getProperty(Configurator.java:75)
    at net.fortuna.ical4j.util.CompatibilityHints.<clinit>(CompatibilityHints.java:87)
    at net.fortuna.ical4j.util.CompatibilityHints.setHintEnabled(CompatibilityHints.java:107)
    at at.bitfire.ical4android.iCalendar.<clinit>(iCalendar.kt:36)
    at at.bitfire.davdroid.resource.LocalEvent.<clinit>(LocalEvent.kt:26)
...
 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.io.Reader.read(char[])' on a null object reference
    at java.util.Properties$LineReader.readLine(Properties.java:435)
    at java.util.Properties.load0(Properties.java:354)
    at java.util.Properties.load(Properties.java:342)
    at net.fortuna.ical4j.util.Configurator.<clinit>(Configurator.java:58)
    at net.fortuna.ical4j.util.Configurator.getProperty(Configurator.java:75) 
    at net.fortuna.ical4j.util.CompatibilityHints.<clinit>(CompatibilityHints.java:87) 
    at net.fortuna.ical4j.util.CompatibilityHints.setHintEnabled(CompatibilityHints.java:107) 
    at at.bitfire.ical4android.iCalendar.<clinit>(iCalendar.kt:36) 
    at at.bitfire.davdroid.resource.LocalEvent.<clinit>(LocalEvent.kt:26) 
...

Using an ical4j.properties file instead of static configuration works as expected.

The same for loading custom aliases from tz.alias, which causes a NullPointerException when the file is not present (this can be easily worked around with an empty file, too).

[rfc2822]

Another problem is that Optional.orElse() is called with an object argument instead of a lambda function:

return property.orElse(new JCacheTimeZoneCache());

This causes new JCacheTimeZoneCache() to be evaluated even when property is already set (to the Map config cache, for instance). This constructor call looks for a JCache implementation, which of course fails when there is no JCache implementation:

Caused by: javax.cache.CacheException: No CachingProviders have been configured
at javax.cache.Caching$CachingProviderRegistry.getCachingProvider(Caching.java:381)
at javax.cache.Caching$CachingProviderRegistry.getCachingProvider(Caching.java:351)
at javax.cache.Caching.getCachingProvider(Caching.java:142)
at net.fortuna.ical4j.util.JCacheTimeZoneCache.<init>(JCacheTimeZoneCache.java:15)

Then it throws a CacheException, which is not catched.

So I suggest to use Optional.orElseGet() [https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html#orElseGet-java.util.function.Supplier-] instead. Using an anonymous Supplier object as lambda pattern will avoid calling the new JCacheTimeZoneCache() constructor.

[benfortuna]

Ok, thanks for pointing out the bug. I've put in a fix now as you suggested - I actually implemented my own Optional class to avoid a dependency on java 8, but wasn't hard to add Supplier also.

I think I fixed the null pointer issue also when ical4j.properties doesn't exist. Let me know if you see further issues.

[omarkilani]

Hi Ben,

We updated from 2.1.0 to 2.1.3 and started seeing this:

Exception in thread "pool-5-thread-16" java.lang.NoClassDefFoundError: javax/cache/configuration/Configuration
        at net.fortuna.ical4j.model.TimeZoneLoader$2.get(TimeZoneLoader.java:283)
        at net.fortuna.ical4j.model.TimeZoneLoader$2.get(TimeZoneLoader.java:280)
        at net.fortuna.ical4j.util.Optional.orElseGet(Optional.java:31)
        at net.fortuna.ical4j.model.TimeZoneLoader.cacheInit(TimeZoneLoader.java:280)
        at net.fortuna.ical4j.model.TimeZoneLoader.<init>(TimeZoneLoader.java:80)
        at net.fortuna.ical4j.model.TimeZoneRegistryImpl.<init>(TimeZoneRegistryImpl.java:125)

Is there some way to opt out of this jcache dependency?

[benfortuna]

Hi Omar,

Yes you can opt out of the jcache dependency by adding the following entry to your configuration (i.e. ical4j.properties):

net.fortuna.ical4j.timezone.cache.impl=net.fortuna.ical4j.util.MapTimeZoneCache

This will override the default caching implementation to use a simple HashMap instead of the more sophisticated Jcache implementation.

The alternative is to just add a Jcache implementation (such as ehcache) to your dependencies.

[stellingsimon]

For those trying to configure the cache implementation: Note that ical4j-2.1.1 uses JCache regardless of what is configured in net.fortuna.ical4j.timezone.cache.impl. I didn't test ical4j-2.1.2.

[omarkilani]

@benfortuna is there any chance you could be convinced to default to MapTimeZoneCache if there's no ical4j.properties found? :)