Update the interface.

api/src/main/java/org/apache/iceberg/VariantLike.java

@@ -18,8 +18,6 @@
  */
 package org.apache.iceberg;
 
-import java.math.BigDecimal;
-
 /**
  * Interface for accessing Variant fields.
  *
@@ -28,25 +26,11 @@
 public interface VariantLike {
   int size();
 
-  VariantLike getFieldByKey(String key);
-
-  VariantLike getFieldAtIndex(int index);
-
-  boolean getBoolean();
-
-  int getInt();
-
-  long getLong();
-
-  float getFloat();
-
-  double getDouble();
-
-  BigDecimal getDecimal();
-
-  String getString();
+  // To access the value of the root element based on the type of provided javaClass.
+  <T> T get(Class<T> javaClass);
 
-  byte[] getBinary();
+  // To access the sub-element for the provided path.
+  VariantLike get(String[] path);
 
   String toJson();
 }

api/src/test/java/org/apache/iceberg/TestAccessors.java

@@ -22,8 +22,12 @@
 import static org.apache.iceberg.types.Types.NestedField.required;
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import java.math.BigDecimal;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
 import java.util.UUID;
 import org.apache.iceberg.TestHelpers.JsonVariant;
 import org.apache.iceberg.TestHelpers.Row;
@@ -250,8 +254,68 @@ public void testEmptySchema() {
   }
 
   @Test
-  public void testVariant() {
-    VariantLike variant = JsonVariant.of("{\"name\":\"John\",\"age\":30}");
+  public void testVariant() throws JsonProcessingException {
+    Base64.Encoder encoder = Base64.getEncoder();
+    boolean expectedTrue = true;
+    boolean expectedFalse = false;
+    int expectedInt = 2147483647;
+    long expectedLong = 2147483648L;
+    float expectedFloat = 1.2345f;
+    double expectedDouble = 1.23456;
+    BigDecimal expectedDecimal = new BigDecimal(123456);
+    String expectedString = "abc";
+    String expectedBytes =
+        new String(encoder.encode(expectedString.getBytes()), StandardCharsets.UTF_8);
+    int nestInt = 10;
+
+    String json =
+        "{\"false\":"
+            + expectedFalse
+            + ", \"true\":"
+            + expectedTrue
+            + ", \"string\": \""
+            + expectedString
+            + "\","
+            + "\"int\":"
+            + expectedInt
+            + ","
+            + "\"long\":"
+            + expectedLong
+            + ", \"float\":"
+            + expectedFloat
+            + ","
+            + "\"double\":"
+            + expectedDouble
+            + ", \"bytes\":\""
+            + expectedBytes
+            + "\", \"decimal\":"
+            + expectedDecimal
+            + ","
+            + "\"nest1\": {\"nest2\":"
+            + nestInt
+            + "}"
+            + "}";
+
+    VariantLike variant = JsonVariant.of(json);
     assertAccessorReturns(Types.VariantType.get(), variant);
+
+    assertThat(variant.get(new String[] {"true"}).get(Boolean.class)).isEqualTo(expectedTrue);
+    assertThat(variant.get(new String[] {"false"}).get(Boolean.class)).isEqualTo(expectedFalse);
+    assertThat(variant.get(new String[] {"string"}).get(String.class)).isEqualTo(expectedString);
+    assertThat(variant.get(new String[] {"int"}).get(Integer.class)).isEqualTo(expectedInt);
+    assertThat(variant.get(new String[] {"long"}).get(Long.class)).isEqualTo(expectedLong);
+    assertThat(variant.get(new String[] {"float"}).get(Float.class)).isEqualTo(expectedFloat);
+    assertThat(variant.get(new String[] {"double"}).get(Double.class)).isEqualTo(expectedDouble);
+    assertThat(variant.get(new String[] {"decimal"}).get(BigDecimal.class))
+        .isEqualTo(expectedDecimal);
+    assertThat(
+            StandardCharsets.UTF_8
+                .decode(variant.get(new String[] {"bytes"}).get(ByteBuffer.class))
+                .toString())
+        .isEqualTo(expectedString);
+    assertThat(variant.get(new String[] {"nest1", "nest2"}).get(Integer.class)).isEqualTo(nestInt);
+    assertThat(variant.get(new String[] {"nest1", "invalid"})).isNull();
+    assertThat(new ObjectMapper().readTree(variant.toJson()))
+        .isEqualTo(new ObjectMapper().readTree(json));
   }
 }

api/src/test/java/org/apache/iceberg/TestHelpers.java

@@ -433,59 +433,43 @@ public int size() {
     }
 
     @Override
-    public VariantLike getFieldByKey(String key) {
-      JsonNode childNode = node.get(key);
-      return new JsonVariant(childNode);
-    }
-
-    @Override
-    public VariantLike getFieldAtIndex(int index) {
-      JsonNode childNode = node.get(index);
-      return new JsonVariant(childNode);
-    }
-
-    @Override
-    public boolean getBoolean() {
-      return node.asBoolean();
-    }
-
-    @Override
-    public int getInt() {
-      return node.asInt();
-    }
-
-    @Override
-    public long getLong() {
-      return node.asLong();
-    }
-
-    @Override
-    public float getFloat() {
-      return (float) node.asDouble();
-    }
-
-    @Override
-    public double getDouble() {
-      return node.asDouble();
-    }
-
-    @Override
-    public BigDecimal getDecimal() {
-      return new BigDecimal(node.asText());
-    }
+    public <T> T get(Class<T> javaClass) {
+      if (javaClass.equals(Boolean.class)) {
+        return (T) (Boolean) node.asBoolean();
+      } else if (javaClass.equals(Integer.class)) {
+        return (T) (Integer) node.asInt();
+      } else if (javaClass.equals(Long.class)) {
+        return (T) (Long) node.asLong();
+      } else if (javaClass.equals(Float.class)) {
+        return (T) Float.valueOf((float) node.asDouble());
+      } else if (javaClass.equals(Double.class)) {
+        return (T) (Double) (node.asDouble());
+      } else if (CharSequence.class.isAssignableFrom(javaClass)) {
+        return (T) node.asText();
+      } else if (javaClass.equals(ByteBuffer.class)) {
+        try {
+          return (T) ByteBuffer.wrap(node.binaryValue());
+        } catch (IOException e) {
+          throw new RuntimeException(e);
+        }
+      } else if (javaClass.equals(BigDecimal.class)) {
+        return (T) node.decimalValue();
+      }
 
-    @Override
-    public String getString() {
-      return node.asText();
+      throw new IllegalArgumentException("Unsupported type: " + javaClass);
     }
 
     @Override
-    public byte[] getBinary() {
-      try {
-        return node.binaryValue();
-      } catch (IOException e) {
-        return null;
+    public VariantLike get(String[] path) {
+      JsonNode childNode = node;
+      for (String pathElement : path) {
+        childNode = childNode.get(pathElement);
+        if (childNode == null) {
+          return null;
+        }
       }
+
+      return new JsonVariant(childNode);
     }
 
     @Override

api/src/test/java/org/apache/iceberg/util/RandomUtil.java

@@ -22,7 +22,6 @@
 import java.math.BigInteger;
 import java.util.Arrays;
 import java.util.Random;
-import org.apache.iceberg.TestHelpers.JsonVariant;
 import org.apache.iceberg.types.Type;
 import org.apache.iceberg.types.Types;
 
@@ -145,9 +144,6 @@ public static Object generatePrimitive(Type.PrimitiveType primitive, Random rand
         BigDecimal bigDecimal = new BigDecimal(unscaled, type.scale());
         return negate(choice) ? bigDecimal.negate() : bigDecimal;
 
-      case VARIANT:
-        return randomVariant();
-
       default:
         throw new IllegalArgumentException(
             "Cannot generate random value for unknown type: " + primitive);
@@ -229,8 +225,4 @@ private static BigInteger randomUnscaled(int precision, Random random) {
 
     return new BigInteger(sb.toString());
   }
-
-  private static JsonVariant randomVariant() {
-    return JsonVariant.of("{\"name\": \"John\"}");
-  }
 }