Uses an iterator that adapts from SymbolToken to String in MacroEvalu…

…atorAsIonReader.iterateTypeAnnotations instead of eagerly allocating a new collection.
amazon-ion · Jan 16, 2025 · 3242f09 · 3242f09
1 parent 50ccac0
commit 3242f09
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Showing 2 changed files with 33 additions and 3 deletions.
diff --git a/src/main/java/com/amazon/ion/impl/macro/MacroEvaluatorAsIonReader.kt b/src/main/java/com/amazon/ion/impl/macro/MacroEvaluatorAsIonReader.kt
@@ -148,10 +148,33 @@ class MacroEvaluatorAsIonReader(
 
     override fun getTypeAnnotations(): Array<String>? = currentValueExpression?.annotations?.let { Array(it.size) { i -> it[i].assumeText() } }
     override fun getTypeAnnotationSymbols(): Array<SymbolToken>? = currentValueExpression?.annotations?.toTypedArray()
-    // TODO: Make this into an iterator that unwraps the SymbolTokens as it goes instead of allocating a new list
+
+    private class SymbolTokenAsStringIterator(val tokens: List<SymbolToken>) : MutableIterator<String> {
+
+        var index = 0
+
+        override fun hasNext(): Boolean {
+            return index < tokens.size
+        }
+
+        override fun next(): String {
+            if (index >= tokens.size) {
+                throw NoSuchElementException()
+            }
+            return tokens[index++].assumeText()
+        }
+
+        override fun remove() {
+            throw UnsupportedOperationException("This iterator does not support removal")
+        }
+    }
+
     override fun iterateTypeAnnotations(): MutableIterator<String> {
-        return currentValueExpression?.annotations?.mapTo(mutableListOf()) { it.assumeText() }?.iterator()
-            ?: return Collections.emptyIterator()
+        return if (currentValueExpression?.annotations?.isNotEmpty() == true) {
+            SymbolTokenAsStringIterator(currentValueExpression!!.annotations)
+        } else {
+            Collections.emptyIterator()
+        }
     }
 
     override fun isInStruct(): Boolean = containerStack.peek()?.container?.type == IonType.STRUCT

diff --git a/src/test/java/com/amazon/ion/impl/EncodingDirectiveCompilationTest.java b/src/test/java/com/amazon/ion/impl/EncodingDirectiveCompilationTest.java
@@ -42,8 +42,10 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.SortedMap;
 import java.util.TreeMap;
 import java.util.function.Consumer;
@@ -1308,6 +1310,11 @@ public void annotationInParameter(InputType inputType, StreamType streamType) th
             String[] annotation = reader.getTypeAnnotations();
             assertEquals(1, annotation.length);
             assertEquals("foo", annotation[0]);
+            Iterator<String> annotationIterator = reader.iterateTypeAnnotations();
+            assertTrue(annotationIterator.hasNext());
+            assertEquals("foo", annotationIterator.next());
+            assertFalse(annotationIterator.hasNext());
+            assertThrows(NoSuchElementException.class, () -> annotationIterator.next());
             assertNull(reader.next());
         }
     }