Java 0.2.5 - Make switch function support lazy evaluation

nlighten-oss · Aug 22, 2024 · 258903d · 258903d
1 parent 767a239
commit 258903d
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Showing 6 changed files with 59 additions and 14 deletions.
diff --git a/java/json-transform/build.gradle b/java/json-transform/build.gradle
@@ -9,7 +9,7 @@ plugins {
 }
 
 group 'co.nlighten'
-version = '0.2.4'
+version = '0.2.5'
 
 ext {
     gsonVersion = "2.10.1"

diff --git a/...on-transform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionIf.java b/...on-transform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionIf.java
@@ -39,7 +39,7 @@ public Object apply(FunctionContext<JE, JA, JO> context) {
             var cje = jArray.get(arr, 0);
             if (adapter.isNull(cje)) {
                 condition = false;
-            } else if (context.isJsonBoolean(cje)) {
+            } else if (adapter.isJsonBoolean(cje)) {
                 condition = adapter.getBoolean(cje);
             } else {
                 condition = adapter.isTruthy(context.transform(cje));

diff --git a/...on-transform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionIs.java b/...on-transform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionIs.java
@@ -56,7 +56,7 @@ public Object apply(FunctionContext<JE, JA, JO> context) {
             JE that = null;
             // if operator is not in/nin then prepare the "that" argument which is a JsonElement
             if (!Objects.equals(op, "IN") && !Objects.equals(op, "NIN")) {
-                that = context.isJsonNumber(value)
+                that = adapter.isJsonNumber(value)
                        ? nullableBigDecimalJsonPrimitive(context, context.getBigDecimal("that"))
                        : context.getJsonElement("that");
             }

diff --git a/...ransform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionSwitch.java b/...ransform/src/main/java/co/nlighten/jsontransform/functions/TransformerFunctionSwitch.java
@@ -30,14 +30,21 @@ public TransformerFunctionSwitch(JsonAdapter<JE, JA, JO> adapter) {
     public Object apply(FunctionContext<JE, JA, JO> context) {
         var alias = context.getAlias();
         var value = context.getString(null);
-        var caseMapEl = context.getJsonElement("cases");
+        var transformed = false;
+        var caseMapEl = context.getJsonElement("cases", false);
+        if (adapter.isJsonString(caseMapEl)) {
+            caseMapEl = context.transform(caseMapEl);
+            transformed = true;
+        }
         if (!jObject.is(caseMapEl)) {
             logger.warn("{}.cases was not specified with an object as case map", alias);
             return null;
         }
         var caseMap = jObject.convert(caseMapEl);
-        return jObject.has(caseMap, value)
-               ? jObject.get(caseMap, value)
-               : context.getJsonElement("default");
+        if (!jObject.has(caseMap, value)) {
+            return context.getJsonElement("default");
+        }
+        var caseValue = jObject.get(caseMap, value);
+        return transformed ? caseValue : context.transform(caseValue);
     }
 }
diff --git a/...n-transform/src/main/java/co/nlighten/jsontransform/functions/common/FunctionContext.java b/...n-transform/src/main/java/co/nlighten/jsontransform/functions/common/FunctionContext.java
@@ -107,12 +107,6 @@ public Object get(String name) {
     public boolean isNull(JE value) {
         return adapter.isNull(value);
     }
-    public boolean isJsonNumber(JE value) {
-        return adapter.isJsonNumber(value);
-    }
-    public boolean isJsonBoolean(JE value) {
-        return adapter.isJsonBoolean(value);
-    }
     public JE wrap(Object value) {
         return adapter.wrap(value);
     }

diff --git a/...form/src/test/java/co/nlighten/jsontransform/functions/TransformerFunctionSwitchTest.java b/...form/src/test/java/co/nlighten/jsontransform/functions/TransformerFunctionSwitchTest.java
@@ -1,11 +1,21 @@
 package co.nlighten.jsontransform.functions;
 
 import co.nlighten.jsontransform.BaseTest;
+import co.nlighten.jsontransform.adapters.gson.GsonJsonTransformer;
+import co.nlighten.jsontransform.functions.common.FunctionContext;
+import co.nlighten.jsontransform.functions.common.TransformerFunction;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
 public class TransformerFunctionSwitchTest extends BaseTest {
     @Test
-    void testObjectFunctionSwitch() {
+    void object() {
         assertTransformation("B",fromJson("""
 {
   "$$switch": "$",
@@ -46,4 +56,38 @@ void inline() {
         assertTransformation(fromJson("{ \"a\": 1, \"B\": 2, \"c\": 3 }"),
                              "$$switch($,'$$decimal:4'):C", fromJson("4"));
     }
+
+
+    @Test
+    void lazyEval() {
+        var transformer = fromJson("""
+{
+  "$$switch": "$",
+  "cases": {
+    "a": "$$switchLazyEval:1",
+    "B": "$$switchLazyEval:2",
+    "c": "$$switchLazyEval:3"
+  }
+}
+""");
+
+        var callCount = new AtomicInteger();
+        GsonJsonTransformer.FUNCTIONS.registerFunctions(Map.entry("switchLazyEval", new TransformerFunction<>(GsonJsonTransformer.ADAPTER) {
+            @Override
+            public Object apply(FunctionContext<JsonElement, JsonArray, JsonObject> context) {
+                callCount.incrementAndGet();
+                return context.get(null);
+            }
+        }));
+
+        callCount.set(0);
+        assertTransformation("B", transformer, "2");
+        // assert that "c" was called twice (check A, check B, break)
+        Assertions.assertEquals(1, callCount.get());
+
+        callCount.set(0);
+        assertTransformation("c", transformer, "3");
+        // assert that "c" was called once (check A, break)
+        Assertions.assertEquals(1, callCount.get());
+    }
 }