src/core/src/main/kotlin/java/Custom.kt

@@ -96,7 +96,6 @@ object Custom {
      * @param writer The writer to which the results should be written
      * @param conn The connection over which the query should be executed
      * @param mapFunc The mapping function to extract the JSON from the query
-     * @return A JSON array of results for the given query
      * @throws DocumentException If parameters are invalid
      */
     @Throws(DocumentException::class)
@@ -116,7 +115,6 @@ object Custom {
      * @param parameters Parameters to use for the query
      * @param writer The writer to which the results should be written
      * @param mapFunc The mapping function to extract the JSON from the query
-     * @return A JSON array of results for the given query
      * @throws DocumentException If parameters are invalid
      */
     @Throws(DocumentException::class)

src/kotlinx/src/main/kotlin/Custom.kt

@@ -2,6 +2,7 @@ package solutions.bitbadger.documents.kotlinx
 
 import solutions.bitbadger.documents.*
 import solutions.bitbadger.documents.Configuration
+import java.io.PrintWriter
 import solutions.bitbadger.documents.java.Custom as CoreCustom
 import java.sql.Connection
 import java.sql.ResultSet
@@ -70,6 +71,40 @@ object Custom {
     fun jsonArray(query: String, parameters: Collection<Parameter<*>> = listOf(), mapFunc: (ResultSet) -> String) =
         CoreCustom.jsonArray(query, parameters, mapFunc)
 
+    /**
+     * Execute a query, writing its JSON array of results to the given `PrintWriter`
+     *
+     * @param query The query to retrieve the results
+     * @param parameters Parameters to use for the query
+     * @param writer The writer to which the results should be written
+     * @param conn The connection over which the query should be executed
+     * @param mapFunc The mapping function to extract the JSON from the query
+     * @throws DocumentException If parameters are invalid
+     */
+    fun writeJsonArray(
+        query: String,
+        parameters: Collection<Parameter<*>> = listOf(),
+        writer: PrintWriter,
+        conn: Connection,
+        mapFunc: (ResultSet) -> String
+    ) = CoreCustom.writeJsonArray(query, parameters, writer, conn, mapFunc)
+
+    /**
+     * Execute a query, writing its JSON array of results to the given `PrintWriter` (creates connection)
+     *
+     * @param query The query to retrieve the results
+     * @param parameters Parameters to use for the query
+     * @param writer The writer to which the results should be written
+     * @param mapFunc The mapping function to extract the JSON from the query
+     * @throws DocumentException If parameters are invalid
+     */
+    fun writeJsonArray(
+        query: String,
+        parameters: Collection<Parameter<*>> = listOf(),
+        writer: PrintWriter,
+        mapFunc: (ResultSet) -> String
+    ) = CoreCustom.writeJsonArray(query, parameters, writer, mapFunc)
+
     /**
      * Execute a query that returns one or no results
      *

src/kotlinx/src/test/kotlin/integration/CustomFunctions.kt

@@ -1,12 +1,17 @@
 package solutions.bitbadger.documents.kotlinx.tests.integration
 
 import solutions.bitbadger.documents.*
+import solutions.bitbadger.documents.java.extensions.countAll
+import solutions.bitbadger.documents.java.extensions.insert
+import solutions.bitbadger.documents.java.extensions.writeCustomJsonArray
 import solutions.bitbadger.documents.kotlinx.Results
 import solutions.bitbadger.documents.kotlinx.extensions.*
 import solutions.bitbadger.documents.kotlinx.tests.ArrayDocument
 import solutions.bitbadger.documents.kotlinx.tests.JsonDocument
 import solutions.bitbadger.documents.kotlinx.tests.TEST_TABLE
 import solutions.bitbadger.documents.query.*
+import java.io.PrintWriter
+import java.io.StringWriter
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
@@ -59,6 +64,40 @@ object CustomFunctions {
         )
     }
 
+    fun writeJsonArrayEmpty(db: ThrowawayDatabase) {
+        assertEquals(0L, db.conn.countAll(TEST_TABLE), "The test table should be empty")
+        val output = StringWriter()
+        val writer = PrintWriter(output)
+        db.conn.writeCustomJsonArray(FindQuery.all(TEST_TABLE), listOf(), writer, Results::jsonFromData)
+        assertEquals("[]", output.toString(), "An empty list was not represented correctly")
+    }
+
+    fun writeJsonArraySingle(db: ThrowawayDatabase) {
+        db.conn.insert(TEST_TABLE, ArrayDocument("one", listOf("2", "3")))
+        val output = StringWriter()
+        val writer = PrintWriter(output)
+        db.conn.writeCustomJsonArray(FindQuery.all(TEST_TABLE), listOf(), writer, Results::jsonFromData)
+        assertEquals(
+            JsonFunctions.maybeJsonB("""[{"id":"one","values":["2","3"]}]"""),
+            output.toString(),
+            "A single document list was not represented correctly"
+        )
+    }
+
+    fun writeJsonArrayMany(db: ThrowawayDatabase) {
+        ArrayDocument.testDocuments.forEach { db.conn.insert(TEST_TABLE, it) }
+        val output = StringWriter()
+        val writer = PrintWriter(output)
+        db.conn.writeCustomJsonArray(FindQuery.all(TEST_TABLE) + orderBy(listOf(Field.named("id"))), listOf(), writer,
+            Results::jsonFromData)
+        assertEquals(
+            JsonFunctions.maybeJsonB("""[{"id":"first","values":["a","b","c"]},"""
+                    + """{"id":"second","values":["c","d","e"]},{"id":"third","values":["x","y","z"]}]"""),
+            output.toString(),
+            "A multiple document list was not represented correctly"
+        )
+    }
+
     fun singleNone(db: ThrowawayDatabase) =
         assertNull(
             db.conn.customSingle(FindQuery.all(TEST_TABLE), mapFunc = Results::fromData),

src/kotlinx/src/test/kotlin/integration/JsonFunctions.kt

@@ -6,6 +6,8 @@ import solutions.bitbadger.documents.Field
 import solutions.bitbadger.documents.FieldMatch
 import solutions.bitbadger.documents.kotlinx.extensions.*
 import solutions.bitbadger.documents.kotlinx.tests.*
+import java.io.PrintWriter
+import java.io.StringWriter
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
@@ -42,9 +44,7 @@ object JsonFunctions {
     private fun docId(id: String) =
         maybeJsonB("{\"id\":\"$id\"")
 
-    fun allDefault(db: ThrowawayDatabase) {
+    private fun checkAllDefault(json: String) {
-        JsonDocument.load(db)
-        val json = db.conn.jsonAll(TEST_TABLE)
         assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
         when (Configuration.dialect()) {
             Dialect.SQLITE -> {
@@ -65,6 +65,19 @@ object JsonFunctions {
         assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
     }
 
+    fun allDefault(db: ThrowawayDatabase) {
+        JsonDocument.load(db)
+        checkAllDefault(db.conn.jsonAll(TEST_TABLE))
+    }
+
+//    fun writeAllDefault(db: ThrowawayDatabase) {
+//        JsonDocument.load(db)
+//        val output = StringWriter()
+//        val writer = PrintWriter(output)
+//        db.conn.writeJsonAll(TEST_TABLE, writer)
+//        checkAllDefault(output.toString())
+//    }
+
     fun allEmpty(db: ThrowawayDatabase) =
         assertEquals("[]", db.conn.jsonAll(TEST_TABLE), "There should have been no documents returned")
 

src/kotlinx/src/test/kotlin/integration/PostgreSQLCustomIT.kt

@@ -35,6 +35,21 @@ class PostgreSQLCustomIT {
     fun jsonArrayMany() =
         PgDB().use(CustomFunctions::jsonArrayMany)
 
+    @Test
+    @DisplayName("writeJsonArray succeeds with empty array")
+    fun writeJsonArrayEmpty() =
+        PgDB().use(CustomFunctions::writeJsonArrayEmpty)
+
+    @Test
+    @DisplayName("writeJsonArray succeeds with a single-item array")
+    fun writeJsonArraySingle() =
+        PgDB().use(CustomFunctions::writeJsonArraySingle)
+
+    @Test
+    @DisplayName("writeJsonArray succeeds with a multi-item array")
+    fun writeJsonArrayMany() =
+        PgDB().use(CustomFunctions::writeJsonArrayMany)
+
     @Test
     @DisplayName("single succeeds when document not found")
     fun singleNone() =

src/kotlinx/src/test/kotlin/integration/SQLiteCustomIT.kt

@@ -34,6 +34,21 @@ class SQLiteCustomIT {
     fun jsonArrayMany() =
         SQLiteDB().use(CustomFunctions::jsonArrayMany)
 
+    @Test
+    @DisplayName("writeJsonArray succeeds with empty array")
+    fun writeJsonArrayEmpty() =
+        SQLiteDB().use(CustomFunctions::writeJsonArrayEmpty)
+
+    @Test
+    @DisplayName("writeJsonArray succeeds with a single-item array")
+    fun writeJsonArraySingle() =
+        SQLiteDB().use(CustomFunctions::writeJsonArraySingle)
+
+    @Test
+    @DisplayName("writeJsonArray succeeds with a multi-item array")
+    fun writeJsonArrayMany() =
+        SQLiteDB().use(CustomFunctions::writeJsonArrayMany)
+
     @Test
     @DisplayName("single succeeds when document not found")
     fun singleNone() =