Use a delegate to make OsisParser cleaner

app/src/androidTest/java/org/bspeice/minimalbible/test/FinalDelegateTest.java

@@ -0,0 +1,39 @@
+package org.bspeice.minimalbible.test;
+
+import org.bspeice.minimalbible.FinalDelegate;
+import org.bspeice.minimalbible.MBTestCase;
+
+import kotlin.PropertyMetadataImpl;
+
+/**
+ * Test that the FinalDelegate actually obeys its contract
+ */
+public class FinalDelegateTest extends MBTestCase {
+
+    FinalDelegate<String> delegate;
+
+    public void setUp() {
+        delegate = new FinalDelegate<String>();
+    }
+
+    public void testDelegateNullSafety() {
+        try {
+            delegate.get(null, new PropertyMetadataImpl(""));
+        } catch (IllegalStateException e) {
+            return;
+        }
+
+        fail("Exception not thrown!");
+    }
+
+    public void testDelegateAssignOnce() {
+        try {
+            delegate.set(null, new PropertyMetadataImpl(""), "");
+            delegate.set(null, new PropertyMetadataImpl(""), "");
+        } catch (IllegalStateException e) {
+            return;
+        }
+
+        fail("Allowed to set twice!");
+    }
+}

app/src/androidTest/java/org/bspeice/minimalbible/test/format/osisparser/OsisParserTest.java

@@ -17,7 +17,7 @@ public class OsisParserTest extends MBTestCase {
     OsisParser parser;
 
     public void setUp() {
-        parser = new OsisParser(null);
+        parser = new OsisParser();
     }
 
     @SuppressLint("NewApi")

app/src/main/java/org/bspeice/minimalbible/service/book/VerseLookupService.java

@@ -80,7 +80,8 @@ public class VerseLookupService implements Action1<Verse> {
         BookData bookData = new BookData(book, v);
         try {
             SAXEventProvider provider = bookData.getSAXEventProvider();
-            OsisParser handler = new OsisParser(v);
+            OsisParser handler = new OsisParser();
+            handler.setVerse(v);
             provider.provideSAXEvents(handler);
             return handler.getVerseContent().toJson();
         } catch (BookException e) {

app/src/main/kotlin/org/bspeice/minimalbible/FinalDelegate.kt

@@ -0,0 +1,24 @@
+package org.bspeice.minimalbible
+
+/**
+ * The purpose of this delegate is to guarantee null-safety, while
+ * also ensuring a pseudo-val type. If you try to read before use, error.
+ * If you try to set multiple times, error.
+ */
+
+public class FinalDelegate<T : Any>() {
+    private var value: T? = null
+    private var didAssign: Boolean = false
+
+    public fun get(thisRef: Any?, desc: PropertyMetadata): T {
+        return value ?: throw IllegalStateException("Property ${desc.name} should be initialized before get")
+    }
+
+    public fun set(thisRef: Any?, desc: PropertyMetadata, value: T) {
+        if (!didAssign) {
+            this.value = value
+            this.didAssign = true
+        } else
+            throw IllegalStateException("Property ${desc.name} should not be assigned multiple times")
+    }
+}

app/src/main/kotlin/org/bspeice/minimalbible/service/format/osisparser/OsisParser.kt

@@ -5,17 +5,20 @@ import org.crosswire.jsword.passage.Verse
 import java.util.ArrayDeque
 import org.xml.sax.Attributes
 import org.crosswire.jsword.book.OSISUtil
+import org.bspeice.minimalbible.FinalDelegate
 
 /**
  * Created by bspeice on 9/10/14.
  */
 
-class OsisParser(v: Verse?) : DefaultHandler() {
+class OsisParser() : DefaultHandler() {
+
+    // Don't pass a verse as part of the constructor, but still guarantee
+    // that it will exist
+    public var verse: Verse by FinalDelegate()
+    val verseContent: VerseContent
+        get() = VerseContent(verse)
 
-    val verseContent: VerseContent? = when (v) {
-        is Verse -> VerseContent(v) // not null
-        else -> null
-    }
     // TODO: Implement a stack to keep min API 8
     val doWrite = ArrayDeque<Boolean>()
 
@@ -33,6 +36,6 @@ class OsisParser(v: Verse?) : DefaultHandler() {
 
     override fun characters(ch: CharArray, start: Int, length: Int) {
         if (doWrite.peek())
-            verseContent?.appendContent(String(ch))
+            verseContent.appendContent(String(ch))
     }
 }

app/src/main/kotlin/org/bspeice/minimalbible/service/format/osisparser/VerseContent.kt

@@ -9,14 +9,17 @@ import java.util.ArrayList
 
 //TODO: JSON Streaming parsing? http://instagram-engineering.tumblr.com/post/97147584853/json-parsing
 class VerseContent(v: Verse) {
-    var id = v.getOrdinal()
-    var bookName = v.getName()
-    var chapter = v.getChapter()
-    var verseNum = v.getVerse()
+    val id = v.getOrdinal()
+    val bookName = v.getName()
+    val chapter = v.getChapter()
+    val verseNum = v.getVerse()
+    val chapterTitle = ""
+    val paraTitle = ""
+    val references: MutableList<VerseReference> = ArrayList()
     var content = ""
-    var chapterTitle = ""
-    var paraTitle = ""
-    var references: MutableList<VerseReference> = ArrayList()
+
+    public val json: String
+        get() = Gson().toJson(this)
 
     public fun toJson(): String {
         // Lazy load Gson - not likely that we'll call this method multiple times, so