[#39723] Implement model for Iceberg side input cache

sdks/java/io/iceberg/src/main/java/org/apache/beam/sdk/io/iceberg/SerializableTableSpec.java

@@ -0,0 +1,219 @@
+/*
+ * 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.beam.sdk.io.iceberg;
+
+import static org.apache.beam.sdk.util.Preconditions.checkStateNotNull;
+
+import com.google.auto.value.AutoValue;
+import java.io.Serializable;
+import java.util.Map;
+import org.apache.beam.sdk.schemas.AutoValueSchema;
+import org.apache.beam.sdk.schemas.NoSuchSchemaException;
+import org.apache.beam.sdk.schemas.SchemaCoder;
+import org.apache.beam.sdk.schemas.SchemaRegistry;
+import org.apache.beam.sdk.schemas.annotations.DefaultSchema;
+import org.apache.beam.sdk.schemas.annotations.SchemaFieldNumber;
+import org.apache.beam.sdk.schemas.annotations.SchemaIgnore;
+import org.apache.iceberg.PartitionSpec;
+import org.apache.iceberg.PartitionSpecParser;
+import org.apache.iceberg.Schema;
+import org.apache.iceberg.SchemaParser;
+import org.apache.iceberg.SortOrder;
+import org.apache.iceberg.SortOrderParser;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.catalog.TableIdentifier;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+
+/**
+ * A serializable, lightweight representation of an Iceberg {@link Table}'s declarative metadata.
+ *
+ * <p>Captures the table's schema, partition spec, sort order, location, properties, and identifier.
+ * Suitable for broadcasting across worker nodes via Beam's side-input mechanism.
+ */
+@DefaultSchema(AutoValueSchema.class)
+@AutoValue
+public abstract class SerializableTableSpec implements Serializable {
+
+  @SchemaFieldNumber("0")
+  public abstract String getTableIdentifierString();
+
+  @SchemaFieldNumber("1")
+  public abstract String getName();
+
+  @SchemaFieldNumber("2")
+  public abstract String getLocation();
+
+  @SchemaFieldNumber("3")
+  public abstract int getSpecId();
+
+  @SchemaFieldNumber("4")
+  public abstract String getSchemaJson();
+
+  @SchemaFieldNumber("5")
+  public abstract String getPartitionSpecJson();
+
+  @SchemaFieldNumber("6")
+  public abstract String getSortOrderJson();
+
+  @SchemaFieldNumber("7")
+  public abstract Map<String, String> getProperties();
+
+  private transient volatile @MonotonicNonNull Schema cachedSchema;
+  private transient volatile @MonotonicNonNull PartitionSpec cachedPartitionSpec;
+  private transient volatile @MonotonicNonNull SortOrder cachedSortOrder;
+  private transient volatile @MonotonicNonNull TableIdentifier cachedTableIdentifier;
+
+  private static volatile @MonotonicNonNull SchemaCoder<SerializableTableSpec> cachedCoder;
+
+  @SchemaIgnore
+  public Schema getSchema() {
+    Schema local = cachedSchema;
+    if (local == null) {
+      synchronized (this) {
+        local = cachedSchema;
+        if (local == null) {
+          cachedSchema = local = SchemaParser.fromJson(getSchemaJson());
+        }
+      }
+    }
+    return local;
+  }
+
+  @SchemaIgnore
+  public PartitionSpec getPartitionSpec() {
+    PartitionSpec local = cachedPartitionSpec;
+    if (local == null) {
+      synchronized (this) {
+        local = cachedPartitionSpec;
+        if (local == null) {
+          cachedPartitionSpec =
+              local = PartitionSpecParser.fromJson(getSchema(), getPartitionSpecJson());
+        }
+      }
+    }
+    return local;
+  }
+
+  @SchemaIgnore
+  public SortOrder getSortOrder() {
+    SortOrder local = cachedSortOrder;
+    if (local == null) {
+      synchronized (this) {
+        local = cachedSortOrder;
+        if (local == null) {
+          cachedSortOrder = local = SortOrderParser.fromJson(getSchema(), getSortOrderJson());
+        }
+      }
+    }
+    return local;
+  }
+
+  @SchemaIgnore
+  public TableIdentifier getTableIdentifier() {
+    TableIdentifier local = cachedTableIdentifier;
+    if (local == null) {
+      synchronized (this) {
+        local = cachedTableIdentifier;
+        if (local == null) {
+          cachedTableIdentifier =
+              local = IcebergUtils.parseTableIdentifier(getTableIdentifierString());
+        }
+      }
+    }
+    return local;
+  }
+
+  public static Builder builder() {
+    return new AutoValue_SerializableTableSpec.Builder();
+  }
+
+  public abstract Builder toBuilder();
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setTableIdentifierString(String tableIdentifierString);
+
+    public abstract Builder setName(String name);
+
+    public abstract Builder setLocation(String location);
+
+    public abstract Builder setSpecId(int specId);
+
+    public abstract Builder setSchemaJson(String schemaJson);
+
+    public abstract Builder setPartitionSpecJson(String partitionSpecJson);
+
+    public abstract Builder setSortOrderJson(String sortOrderJson);
+
+    public abstract Builder setProperties(Map<String, String> properties);
+
+    public abstract SerializableTableSpec build();
+  }
+
+  /**
+   * Constructs a {@link SerializableTableSpec} from a {@link Table}, using {@link Table#name()} as
+   * the table identifier string.
+   *
+   * <p>Note: When possible, prefer {@link #fromTable(TableIdentifier, Table)} to avoid catalog name
+   * prefix ambiguities in {@link Table#name()}.
+   */
+  public static SerializableTableSpec fromTable(Table table) {
+    return fromTable(table.name(), table);
+  }
+
+  /**
+   * Constructs a {@link SerializableTableSpec} from a {@link TableIdentifier} and a {@link Table}.
+   */
+  public static SerializableTableSpec fromTable(TableIdentifier tableIdentifier, Table table) {
+    return fromTable(IcebergUtils.tableIdentifierToString(tableIdentifier), table);
+  }
+
+  /**
+   * Constructs a {@link SerializableTableSpec} from an explicit table identifier string and a
+   * {@link Table}.
+   */
+  public static SerializableTableSpec fromTable(String tableIdentifierString, Table table) {
+    return builder()
+        .setTableIdentifierString(tableIdentifierString)
+        .setName(table.name())
+        .setLocation(table.location())
+        .setSpecId(table.spec().specId())
+        .setSchemaJson(SchemaParser.toJson(table.schema()))
+        .setPartitionSpecJson(PartitionSpecParser.toJson(table.spec()))
+        .setSortOrderJson(SortOrderParser.toJson(table.sortOrder()))
+        .setProperties(table.properties())
+        .build();
+  }
+
+  /** Returns the cached {@link SchemaCoder} for {@link SerializableTableSpec}. */
+  public static SchemaCoder<SerializableTableSpec> getCoder() {
+    if (cachedCoder == null) {
+      synchronized (SerializableTableSpec.class) {
+        if (cachedCoder == null) {
+          try {
+            cachedCoder =
+                SchemaRegistry.createDefault().getSchemaCoder(SerializableTableSpec.class);
+          } catch (NoSuchSchemaException e) {
+            throw new RuntimeException(e);
+          }
+        }
+      }
+    }
+    return checkStateNotNull(cachedCoder);
+  }
+}