Replace ChannelEnumerator by ListEnumerator.

vitrivr-engine-index/src/main/kotlin/org/vitrivr/engine/index/enumerate/ListEnumerator.kt

@@ -0,0 +1,53 @@
+package org.vitrivr.engine.index.enumerate
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import org.vitrivr.engine.core.context.IndexContext
+import org.vitrivr.engine.core.operators.ingest.Enumerator
+import org.vitrivr.engine.core.operators.ingest.EnumeratorFactory
+import org.vitrivr.engine.core.source.Source
+import java.util.LinkedList
+
+/**
+ * A [Enumerator] that allows a caller to explicitly prepare a list of [Source]s to enumerate.
+ *
+ * @author Ralph Gasser
+ * @version 1.0.0
+ */
+class ListEnumerator : EnumeratorFactory {
+
+    /**
+     * Creates a new [Enumerator] instance from this [ListEnumerator].
+     *
+     * @param context The [IndexContext] to use.
+     * @param parameters Optional set of parameters.
+     */
+    override fun newOperator(context: IndexContext, parameters: Map<String, String>): Enumerator {
+        return Instance(context)
+    }
+
+    /**
+     * The [Enumerator] returned by this [FileSystemEnumerator].
+     */
+    private class Instance(private val context: IndexContext) : Enumerator {
+
+        /** List of [Source]s that should be enumerated. */
+        private val list: LinkedList<Source> = LinkedList()
+
+        override fun toFlow(scope: CoroutineScope): Flow<Source> = flow {
+            for (s in this@Instance.list) {
+                emit(s)
+            }
+        }
+
+        /**
+         * Enqueues a new [Source].
+         *
+         * @param source [Source] to add.
+         */
+        fun add(source: Source) {
+            this.list.add(source)
+        }
+    }
+}

vitrivr-engine-index/src/main/resources/META-INF/services/org.vitrivr.engine.core.operators.ingest.EnumeratorFactory

@@ -1,3 +1,3 @@
 org.vitrivr.engine.index.enumerate.FileSystemEnumerator
 org.vitrivr.engine.index.enumerate.ApiEnumerator
-org.vitrivr.engine.index.enumerate.ChannelEnumerator
+org.vitrivr.engine.index.enumerate.ListEnumerator