Core: View history entry core implementation (apache#6565)

Co-authored-by: John Zhuge <jzhuge@apache.org>

Author: amogh-jahagirdar

api/src/main/java/org/apache/iceberg/view/ViewHistoryEntry.java

@@ -18,12 +18,15 @@
  */
 package org.apache.iceberg.view;
 
+import org.immutables.value.Value;
+
 /**
  * View history entry.
  *
  * <p>An entry contains a change to the view state. At the given timestamp, the current version was
  * set to the given version ID.
  */
+@Value.Immutable
 public interface ViewHistoryEntry {
   /** Return the timestamp in milliseconds of the change */
   long timestampMillis();

core/src/main/java/org/apache/iceberg/view/ViewHistoryEntryParser.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.iceberg.view;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonNode;
+import java.io.IOException;
+import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
+import org.apache.iceberg.util.JsonUtil;
+
+class ViewHistoryEntryParser {
+
+  private ViewHistoryEntryParser() {}
+
+  static final String VERSION_ID = "version-id";
+  static final String TIMESTAMP_MS = "timestamp-ms";
+
+  static String toJson(ViewHistoryEntry entry) {
+    return JsonUtil.generate(gen -> toJson(entry, gen), false);
+  }
+
+  static void toJson(ViewHistoryEntry entry, JsonGenerator generator) throws IOException {
+    Preconditions.checkArgument(entry != null, "Invalid view history entry: null");
+    generator.writeStartObject();
+    generator.writeNumberField(TIMESTAMP_MS, entry.timestampMillis());
+    generator.writeNumberField(VERSION_ID, entry.versionId());
+    generator.writeEndObject();
+  }
+
+  static ViewHistoryEntry fromJson(String json) {
+    return JsonUtil.parse(json, ViewHistoryEntryParser::fromJson);
+  }
+
+  static ViewHistoryEntry fromJson(JsonNode node) {
+    Preconditions.checkArgument(node != null, "Cannot parse view history entry from null object");
+    Preconditions.checkArgument(
+        node.isObject(), "Cannot parse view history entry from non-object: %s", node);
+    return ImmutableViewHistoryEntry.builder()
+        .versionId(JsonUtil.getInt(VERSION_ID, node))
+        .timestampMillis(JsonUtil.getLong(TIMESTAMP_MS, node))
+        .build();
+  }
+}

core/src/test/java/org/apache/iceberg/view/TestViewHistoryEntryParser.java

@@ -0,0 +1,76 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.iceberg.view;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import org.assertj.core.api.Assertions;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestViewHistoryEntryParser {
+
+  @Test
+  public void testViewHistoryEntryFromJson() {
+    String json = "{\"timestamp-ms\":123,\"version-id\":1}";
+    ViewHistoryEntry viewHistoryEntry =
+        ImmutableViewHistoryEntry.builder().versionId(1).timestampMillis(123).build();
+    Assert.assertEquals(
+        "Should be able to deserialize valid view history entry",
+        viewHistoryEntry,
+        ViewHistoryEntryParser.fromJson(json));
+  }
+
+  @Test
+  public void testViewHistoryEntryToJson() {
+    String json = "{\"timestamp-ms\":123,\"version-id\":1}";
+    ViewHistoryEntry viewHistoryEntry =
+        ImmutableViewHistoryEntry.builder().versionId(1).timestampMillis(123).build();
+    Assert.assertEquals(
+        "Should be able to serialize view history entry",
+        json,
+        ViewHistoryEntryParser.toJson(viewHistoryEntry));
+  }
+
+  @Test
+  public void testNullViewHistoryEntry() {
+    Assertions.assertThatThrownBy(() -> ViewHistoryEntryParser.fromJson((JsonNode) null))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Cannot parse view history entry from null object");
+
+    Assertions.assertThatThrownBy(() -> ViewHistoryEntryParser.toJson(null))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Invalid view history entry: null");
+  }
+
+  @Test
+  public void testViewHistoryEntryMissingFields() {
+    Assertions.assertThatThrownBy(() -> ViewHistoryEntryParser.fromJson("{}"))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Cannot parse missing int: version-id");
+
+    Assertions.assertThatThrownBy(
+            () -> ViewHistoryEntryParser.fromJson("{\"timestamp-ms\":\"123\"}"))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Cannot parse missing int: version-id");
+
+    Assertions.assertThatThrownBy(() -> ViewHistoryEntryParser.fromJson("{\"version-id\":1}"))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Cannot parse missing long: timestamp-ms");
+  }
+}