Remove unnecssary contextClassLoader checks (#199)

* Remove thread context class loader checks and remove Ical4Android class

* Add test for ical4j ServiceLoader without per-thread context class loader

Author: rfc2822

lib/src/main/kotlin/at/bitfire/ical4android/Event.kt

@@ -243,8 +243,6 @@ data class Event(
 
 
     fun write(os: OutputStream) {
-        Ical4Android.checkThreadContextClassLoader()
-
         val ical = Calendar()
         ical.properties += Version.VERSION_2_0
         ical.properties += prodId()

lib/src/main/kotlin/at/bitfire/ical4android/ICalendar.kt

@@ -4,6 +4,7 @@
 
 package at.bitfire.ical4android
 
+import at.bitfire.ical4android.ICalendar.Companion.CALENDAR_NAME
 import at.bitfire.ical4android.validation.ICalPreprocessor
 import net.fortuna.ical4j.data.CalendarBuilder
 import net.fortuna.ical4j.data.CalendarParserFactory
@@ -80,7 +81,6 @@ open class ICalendar {
          * @throws IllegalArgumentException when the iCalendar resource contains an invalid value
          */
         fun fromReader(reader: Reader, properties: MutableMap<String, String>? = null): Calendar {
-            Ical4Android.checkThreadContextClassLoader()
             logger.fine("Parsing iCalendar stream")
 
             // preprocess stream to work around some problems that can't be fixed later
@@ -229,7 +229,6 @@ open class ICalendar {
          * @return time zone id (TZID) if VTIMEZONE contains a TZID, null otherwise
          */
         fun timezoneDefToTzId(timezoneDef: String): String? {
-            Ical4Android.checkThreadContextClassLoader()
             try {
                 val builder = CalendarBuilder()
                 val cal = builder.build(StringReader(timezoneDef))

lib/src/main/kotlin/at/bitfire/ical4android/Ical4Android.kt renamed to lib/src/main/kotlin/at/bitfire/ical4android/Ical4jVersion.kt

@@ -4,15 +4,8 @@
 
 package at.bitfire.ical4android
 
+/**
+ * The used version of ical4j.
+ */
 @Suppress("unused")
-object Ical4Android {
-
-    const val ical4jVersion = BuildConfig.version_ical4j
-
-
-    fun checkThreadContextClassLoader() {
-        if (Thread.currentThread().contextClassLoader == null)
-            throw IllegalStateException("Thread.currentThread().contextClassLoader must be set for java.util.ServiceLoader (used by ical4j)")
-    }
-
-}
+const val ical4jVersion = BuildConfig.version_ical4j

lib/src/main/kotlin/at/bitfire/ical4android/JtxICalObject.kt

@@ -47,7 +47,42 @@ import net.fortuna.ical4j.model.parameter.Rsvp
 import net.fortuna.ical4j.model.parameter.SentBy
 import net.fortuna.ical4j.model.parameter.Value
 import net.fortuna.ical4j.model.parameter.XParameter
-import net.fortuna.ical4j.model.property.*
+import net.fortuna.ical4j.model.property.Action
+import net.fortuna.ical4j.model.property.Attach
+import net.fortuna.ical4j.model.property.Categories
+import net.fortuna.ical4j.model.property.Clazz
+import net.fortuna.ical4j.model.property.Color
+import net.fortuna.ical4j.model.property.Comment
+import net.fortuna.ical4j.model.property.Completed
+import net.fortuna.ical4j.model.property.Contact
+import net.fortuna.ical4j.model.property.Created
+import net.fortuna.ical4j.model.property.Description
+import net.fortuna.ical4j.model.property.DtEnd
+import net.fortuna.ical4j.model.property.DtStamp
+import net.fortuna.ical4j.model.property.DtStart
+import net.fortuna.ical4j.model.property.Due
+import net.fortuna.ical4j.model.property.Duration
+import net.fortuna.ical4j.model.property.ExDate
+import net.fortuna.ical4j.model.property.Geo
+import net.fortuna.ical4j.model.property.LastModified
+import net.fortuna.ical4j.model.property.Location
+import net.fortuna.ical4j.model.property.PercentComplete
+import net.fortuna.ical4j.model.property.Priority
+import net.fortuna.ical4j.model.property.ProdId
+import net.fortuna.ical4j.model.property.RDate
+import net.fortuna.ical4j.model.property.RRule
+import net.fortuna.ical4j.model.property.RecurrenceId
+import net.fortuna.ical4j.model.property.RelatedTo
+import net.fortuna.ical4j.model.property.Repeat
+import net.fortuna.ical4j.model.property.Resources
+import net.fortuna.ical4j.model.property.Sequence
+import net.fortuna.ical4j.model.property.Status
+import net.fortuna.ical4j.model.property.Summary
+import net.fortuna.ical4j.model.property.Trigger
+import net.fortuna.ical4j.model.property.Uid
+import net.fortuna.ical4j.model.property.Url
+import net.fortuna.ical4j.model.property.Version
+import net.fortuna.ical4j.model.property.XProperty
 import java.io.FileNotFoundException
 import java.io.IOException
 import java.io.OutputStream
@@ -593,8 +628,6 @@ open class JtxICalObject(
      * @return The current JtxICalObject transformed into a ical4j Calendar
      */
     fun getICalendarFormat(): Calendar? {
-        Ical4Android.checkThreadContextClassLoader()
-
         val ical = Calendar()
         ical.properties += Version.VERSION_2_0
         ical.properties += ICalendar.prodId(listOf(TaskProvider.ProviderName.JtxBoard.packageName))
@@ -697,7 +730,6 @@ open class JtxICalObject(
      * @param [os] OutputStream where iCalendar should be written to
      */
     fun write(os: OutputStream) {
-        Ical4Android.checkThreadContextClassLoader()
         CalendarOutputter(false).output(this.getICalendarFormat(), os)
     }
 

lib/src/main/kotlin/at/bitfire/ical4android/Task.kt

@@ -193,8 +193,6 @@ data class Task(
 
 
     fun write(os: OutputStream) {
-        Ical4Android.checkThreadContextClassLoader()
-
         val ical = Calendar()
         ical.properties += Version.VERSION_2_0
         ical.properties += prodId()

lib/src/main/kotlin/at/bitfire/ical4android/util/AndroidTimeUtils.kt

@@ -7,11 +7,14 @@
 package at.bitfire.ical4android.util
 
 import android.text.format.Time
-import at.bitfire.ical4android.Ical4Android
+import at.bitfire.ical4android.util.AndroidTimeUtils.androidifyTimeZone
+import at.bitfire.ical4android.util.AndroidTimeUtils.storageTzId
 import at.bitfire.ical4android.util.TimeApiExtensions.toLocalDate
 import at.bitfire.ical4android.util.TimeApiExtensions.toZonedDateTime
-import net.fortuna.ical4j.model.*
 import net.fortuna.ical4j.model.Date
+import net.fortuna.ical4j.model.DateList
+import net.fortuna.ical4j.model.DateTime
+import net.fortuna.ical4j.model.TemporalAmountAdapter
 import net.fortuna.ical4j.model.TimeZone
 import net.fortuna.ical4j.model.parameter.Value
 import net.fortuna.ical4j.model.property.DateListProperty
@@ -27,7 +30,8 @@ import java.time.ZoneOffset
 import java.time.ZonedDateTime
 import java.time.format.DateTimeFormatter
 import java.time.temporal.TemporalAmount
-import java.util.*
+import java.util.LinkedList
+import java.util.Locale
 import java.util.logging.Logger
 
 object AndroidTimeUtils {

lib/src/main/kotlin/at/bitfire/ical4android/util/DateUtils.kt

@@ -4,7 +4,6 @@
 
 package at.bitfire.ical4android.util
 
-import at.bitfire.ical4android.Ical4Android
 import net.fortuna.ical4j.data.CalendarBuilder
 import net.fortuna.ical4j.model.Date
 import net.fortuna.ical4j.model.DateTime
@@ -24,10 +23,6 @@ import java.util.logging.Logger
  */
 object DateUtils {
 
-    init {
-        Ical4Android.checkThreadContextClassLoader()
-    }
-
     private val logger
         get() = Logger.getLogger(javaClass.name)
 
@@ -130,8 +125,6 @@ object DateUtils {
      * @return parsed [VTimeZone], or `null` when the timezone definition can't be parsed
      */
     fun parseVTimeZone(timezoneDef: String): VTimeZone? {
-        Ical4Android.checkThreadContextClassLoader()
-
         val builder = CalendarBuilder(tzRegistry)
         try {
             val cal = builder.build(StringReader(timezoneDef))

lib/src/test/kotlin/at/bitfire/ical4android/Ical4jServiceLoaderTest.kt

@@ -0,0 +1,31 @@
+package at.bitfire.ical4android
+
+import net.fortuna.ical4j.data.CalendarBuilder
+import net.fortuna.ical4j.model.Component
+import net.fortuna.ical4j.model.component.VEvent
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import java.io.StringReader
+
+class Ical4jServiceLoaderTest {
+
+    @Test
+    fun Ical4j_ServiceLoader_DoesntNeedContextClassLoader() {
+        Thread.currentThread().contextClassLoader = null
+
+        val iCal = "BEGIN:VCALENDAR\n" +
+                "PRODID:-//xyz Corp//NONSGML PDA Calendar Version 1.0//EN\n" +
+                "VERSION:2.0\n" +
+                "BEGIN:VEVENT\n" +
+                "UID:[email protected]\n" +
+                "DTSTART:19960918T143000Z\n" +
+                "DTEND:19960920T220000Z\n" +
+                "SUMMARY:Networld+Interop Conference\n" +
+                "END:VEVENT\n" +
+                "END:VCALENDAR\n"
+        val result = CalendarBuilder().build(StringReader(iCal))
+        val vEvent = result.getComponent<VEvent>(Component.VEVENT)
+        assertEquals("Networld+Interop Conference", vEvent.summary.value)
+    }
+
+}