core/src/main/java/org/apache/iceberg/TableMetadataParser.java - iceberg - Git at Google

 /*
  * 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;

 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.JsonNode;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.StringWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 import org.apache.iceberg.TableMetadata.MetadataLogEntry;
 import org.apache.iceberg.TableMetadata.SnapshotLogEntry;
 import org.apache.iceberg.exceptions.RuntimeIOException;
 import org.apache.iceberg.io.FileIO;
 import org.apache.iceberg.io.InputFile;
 import org.apache.iceberg.io.OutputFile;
 import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
 import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList;
 import org.apache.iceberg.relocated.com.google.common.collect.Lists;
 import org.apache.iceberg.util.JsonUtil;

 public class TableMetadataParser {

   public enum Codec {
     NONE(""),
     GZIP(".gz");

     private final String extension;

     Codec(String extension) {
       this.extension = extension;
     }

     public static Codec fromName(String codecName) {
       Preconditions.checkArgument(codecName != null, "Codec name is null");
       return Codec.valueOf(codecName.toUpperCase(Locale.ENGLISH));
     }

     public static Codec fromFileName(String fileName) {
       Preconditions.checkArgument(fileName.contains(".metadata.json"),
           "%s is not a valid metadata file", fileName);
       // we have to be backward-compatible with .metadata.json.gz files
       if (fileName.endsWith(".metadata.json.gz")) {
         return Codec.GZIP;
       }
       String fileNameWithoutSuffix = fileName.substring(0, fileName.lastIndexOf(".metadata.json"));
       if (fileNameWithoutSuffix.endsWith(Codec.GZIP.extension)) {
         return Codec.GZIP;
       } else {
         return Codec.NONE;
       }
     }
   }

   private TableMetadataParser() {
   }

   // visible for testing
   static final String FORMAT_VERSION = "format-version";
   static final String TABLE_UUID = "table-uuid";
   static final String LOCATION = "location";
   static final String LAST_SEQUENCE_NUMBER = "last-sequence-number";
   static final String LAST_UPDATED_MILLIS = "last-updated-ms";
   static final String LAST_COLUMN_ID = "last-column-id";
   static final String SCHEMA = "schema";
   static final String PARTITION_SPEC = "partition-spec";
   static final String PARTITION_SPECS = "partition-specs";
   static final String DEFAULT_SPEC_ID = "default-spec-id";
   static final String DEFAULT_SORT_ORDER_ID = "default-sort-order-id";
   static final String SORT_ORDERS = "sort-orders";
   static final String PROPERTIES = "properties";
   static final String CURRENT_SNAPSHOT_ID = "current-snapshot-id";
   static final String SNAPSHOTS = "snapshots";
   static final String SNAPSHOT_ID = "snapshot-id";
   static final String TIMESTAMP_MS = "timestamp-ms";
   static final String SNAPSHOT_LOG = "snapshot-log";
   static final String METADATA_FILE = "metadata-file";
   static final String METADATA_LOG = "metadata-log";

   public static void overwrite(TableMetadata metadata, OutputFile outputFile) {
     internalWrite(metadata, outputFile, true);
   }

   public static void write(TableMetadata metadata, OutputFile outputFile) {
     internalWrite(metadata, outputFile, false);
   }

   public static void internalWrite(
       TableMetadata metadata, OutputFile outputFile, boolean overwrite) {
     boolean isGzip = Codec.fromFileName(outputFile.location()) == Codec.GZIP;
     OutputStream stream = overwrite ? outputFile.createOrOverwrite() : outputFile.create();
     try (OutputStream ou = isGzip ? new GZIPOutputStream(stream) : stream;
          OutputStreamWriter writer = new OutputStreamWriter(ou, StandardCharsets.UTF_8)) {
       JsonGenerator generator = JsonUtil.factory().createGenerator(writer);
       generator.useDefaultPrettyPrinter();
       toJson(metadata, generator);
       generator.flush();
     } catch (IOException e) {
       throw new RuntimeIOException(e, "Failed to write json to file: %s", outputFile);
     }
   }

   public static String getFileExtension(String codecName) {
     return getFileExtension(Codec.fromName(codecName));
   }

   public static String getFileExtension(Codec codec) {
     return codec.extension + ".metadata.json";
   }

   public static String getOldFileExtension(Codec codec) {
     // we have to be backward-compatible with .metadata.json.gz files
     return ".metadata.json" + codec.extension;
   }

   public static String toJson(TableMetadata metadata) {
     try (StringWriter writer = new StringWriter()) {
       JsonGenerator generator = JsonUtil.factory().createGenerator(writer);
       toJson(metadata, generator);
       generator.flush();
       return writer.toString();
     } catch (IOException e) {
       throw new RuntimeIOException(e, "Failed to write json for: %s", metadata);
     }
   }

   private static void toJson(TableMetadata metadata, JsonGenerator generator) throws IOException {
     generator.writeStartObject();

     generator.writeNumberField(FORMAT_VERSION, metadata.formatVersion());
     generator.writeStringField(TABLE_UUID, metadata.uuid());
     generator.writeStringField(LOCATION, metadata.location());
     if (metadata.formatVersion() > 1) {
       generator.writeNumberField(LAST_SEQUENCE_NUMBER, metadata.lastSequenceNumber());
     }
     generator.writeNumberField(LAST_UPDATED_MILLIS, metadata.lastUpdatedMillis());
     generator.writeNumberField(LAST_COLUMN_ID, metadata.lastColumnId());

     generator.writeFieldName(SCHEMA);
     SchemaParser.toJson(metadata.schema(), generator);

     // for older readers, continue writing the default spec as "partition-spec"
     if (metadata.formatVersion() == 1) {
       generator.writeFieldName(PARTITION_SPEC);
       PartitionSpecParser.toJsonFields(metadata.spec(), generator);
     }

     // write the default spec ID and spec list
     generator.writeNumberField(DEFAULT_SPEC_ID, metadata.defaultSpecId());
     generator.writeArrayFieldStart(PARTITION_SPECS);
     for (PartitionSpec spec : metadata.specs()) {
       PartitionSpecParser.toJson(spec, generator);
     }
     generator.writeEndArray();

     generator.writeNumberField(DEFAULT_SORT_ORDER_ID, metadata.defaultSortOrderId());
     generator.writeArrayFieldStart(SORT_ORDERS);
     for (SortOrder sortOrder : metadata.sortOrders()) {
       SortOrderParser.toJson(sortOrder, generator);
     }
     generator.writeEndArray();

     generator.writeObjectFieldStart(PROPERTIES);
     for (Map.Entry<String, String> keyValue : metadata.properties().entrySet()) {
       generator.writeStringField(keyValue.getKey(), keyValue.getValue());
     }
     generator.writeEndObject();

     generator.writeNumberField(CURRENT_SNAPSHOT_ID,
         metadata.currentSnapshot() != null ? metadata.currentSnapshot().snapshotId() : -1);

     generator.writeArrayFieldStart(SNAPSHOTS);
     for (Snapshot snapshot : metadata.snapshots()) {
       SnapshotParser.toJson(snapshot, generator);
     }
     generator.writeEndArray();

     generator.writeArrayFieldStart(SNAPSHOT_LOG);
     for (HistoryEntry logEntry : metadata.snapshotLog()) {
       generator.writeStartObject();
       generator.writeNumberField(TIMESTAMP_MS, logEntry.timestampMillis());
       generator.writeNumberField(SNAPSHOT_ID, logEntry.snapshotId());
       generator.writeEndObject();
     }
     generator.writeEndArray();

     generator.writeArrayFieldStart(METADATA_LOG);
     for (MetadataLogEntry logEntry : metadata.previousFiles()) {
       generator.writeStartObject();
       generator.writeNumberField(TIMESTAMP_MS, logEntry.timestampMillis());
       generator.writeStringField(METADATA_FILE, logEntry.file());
       generator.writeEndObject();
     }
     generator.writeEndArray();

     generator.writeEndObject();
   }

   /**
    * @deprecated will be removed in 0.9.0; use read(FileIO, InputFile) instead.
    */
   @Deprecated
   public static TableMetadata read(TableOperations ops, InputFile file) {
     return read(ops.io(), file);
   }

   public static TableMetadata read(FileIO io, String path) {
     return read(io, io.newInputFile(path));
   }

   public static TableMetadata read(FileIO io, InputFile file) {
     Codec codec = Codec.fromFileName(file.location());
     try (InputStream is = codec == Codec.GZIP ? new GZIPInputStream(file.newStream()) : file.newStream()) {
       return fromJson(io, file, JsonUtil.mapper().readValue(is, JsonNode.class));
     } catch (IOException e) {
       throw new RuntimeIOException(e, "Failed to read file: %s", file);
     }
   }

   static TableMetadata fromJson(FileIO io, InputFile file, JsonNode node) {
     Preconditions.checkArgument(node.isObject(),
         "Cannot parse metadata from a non-object: %s", node);

     int formatVersion = JsonUtil.getInt(FORMAT_VERSION, node);
     Preconditions.checkArgument(formatVersion <= TableMetadata.SUPPORTED_TABLE_FORMAT_VERSION,
         "Cannot read unsupported version %s", formatVersion);

     String uuid = JsonUtil.getStringOrNull(TABLE_UUID, node);
     String location = JsonUtil.getString(LOCATION, node);
     long lastSequenceNumber;
     if (formatVersion > 1) {
       lastSequenceNumber = JsonUtil.getLong(LAST_SEQUENCE_NUMBER, node);
     } else {
       lastSequenceNumber = TableMetadata.INITIAL_SEQUENCE_NUMBER;
     }
     int lastAssignedColumnId = JsonUtil.getInt(LAST_COLUMN_ID, node);
     Schema schema = SchemaParser.fromJson(node.get(SCHEMA));

     JsonNode specArray = node.get(PARTITION_SPECS);
     List<PartitionSpec> specs;
     int defaultSpecId;
     if (specArray != null) {
       Preconditions.checkArgument(specArray.isArray(),
           "Cannot parse partition specs from non-array: %s", specArray);
       // default spec ID is required when the spec array is present
       defaultSpecId = JsonUtil.getInt(DEFAULT_SPEC_ID, node);

       // parse the spec array
       ImmutableList.Builder<PartitionSpec> builder = ImmutableList.builder();
       for (JsonNode spec : specArray) {
         builder.add(PartitionSpecParser.fromJson(schema, spec));
       }
       specs = builder.build();

     } else {
       Preconditions.checkArgument(formatVersion == 1,
           "%s must exist in format v%s", PARTITION_SPECS, formatVersion);
       // partition spec is required for older readers, but is always set to the default if the spec
       // array is set. it is only used to default the spec map is missing, indicating that the
       // table metadata was written by an older writer.
       defaultSpecId = TableMetadata.INITIAL_SPEC_ID;
       specs = ImmutableList.of(PartitionSpecParser.fromJsonFields(
           schema, TableMetadata.INITIAL_SPEC_ID, node.get(PARTITION_SPEC)));
     }

     JsonNode sortOrderArray = node.get(SORT_ORDERS);
     List<SortOrder> sortOrders;
     int defaultSortOrderId;
     if (sortOrderArray != null) {
       defaultSortOrderId = JsonUtil.getInt(DEFAULT_SORT_ORDER_ID, node);
       ImmutableList.Builder<SortOrder> sortOrdersBuilder = ImmutableList.builder();
       for (JsonNode sortOrder : sortOrderArray) {
         sortOrdersBuilder.add(SortOrderParser.fromJson(schema, sortOrder));
       }
       sortOrders = sortOrdersBuilder.build();
     } else {
       Preconditions.checkArgument(formatVersion == 1,
           "%s must exist in format v%s", SORT_ORDERS, formatVersion);
       SortOrder defaultSortOrder = SortOrder.unsorted();
       sortOrders = ImmutableList.of(defaultSortOrder);
       defaultSortOrderId = defaultSortOrder.orderId();
     }

     Map<String, String> properties = JsonUtil.getStringMap(PROPERTIES, node);
     long currentVersionId = JsonUtil.getLong(CURRENT_SNAPSHOT_ID, node);
     long lastUpdatedMillis = JsonUtil.getLong(LAST_UPDATED_MILLIS, node);

     JsonNode snapshotArray = node.get(SNAPSHOTS);
     Preconditions.checkArgument(snapshotArray.isArray(),
         "Cannot parse snapshots from non-array: %s", snapshotArray);

     List<Snapshot> snapshots = Lists.newArrayListWithExpectedSize(snapshotArray.size());
     Iterator<JsonNode> iterator = snapshotArray.elements();
     while (iterator.hasNext()) {
       snapshots.add(SnapshotParser.fromJson(io, iterator.next()));
     }

     ImmutableList.Builder<HistoryEntry> entries = ImmutableList.builder();
     if (node.has(SNAPSHOT_LOG)) {
       Iterator<JsonNode> logIterator = node.get(SNAPSHOT_LOG).elements();
       while (logIterator.hasNext()) {
         JsonNode entryNode = logIterator.next();
         entries.add(new SnapshotLogEntry(
             JsonUtil.getLong(TIMESTAMP_MS, entryNode), JsonUtil.getLong(SNAPSHOT_ID, entryNode)));
       }
     }

     ImmutableList.Builder<MetadataLogEntry> metadataEntries = ImmutableList.builder();
     if (node.has(METADATA_LOG)) {
       Iterator<JsonNode> logIterator = node.get(METADATA_LOG).elements();
       while (logIterator.hasNext()) {
         JsonNode entryNode = logIterator.next();
         metadataEntries.add(new MetadataLogEntry(
                 JsonUtil.getLong(TIMESTAMP_MS, entryNode), JsonUtil.getString(METADATA_FILE, entryNode)));
       }
     }

     return new TableMetadata(file, formatVersion, uuid, location,
         lastSequenceNumber, lastUpdatedMillis, lastAssignedColumnId, schema, defaultSpecId, specs,
         defaultSortOrderId, sortOrders, properties, currentVersionId, snapshots, entries.build(),
         metadataEntries.build());
   }
 }
	/*
	* 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;

	import com.fasterxml.jackson.core.JsonGenerator;
	import com.fasterxml.jackson.databind.JsonNode;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.io.OutputStreamWriter;
	import java.io.StringWriter;
	import java.nio.charset.StandardCharsets;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Locale;
	import java.util.Map;
	import java.util.zip.GZIPInputStream;
	import java.util.zip.GZIPOutputStream;
	import org.apache.iceberg.TableMetadata.MetadataLogEntry;
	import org.apache.iceberg.TableMetadata.SnapshotLogEntry;
	import org.apache.iceberg.exceptions.RuntimeIOException;
	import org.apache.iceberg.io.FileIO;
	import org.apache.iceberg.io.InputFile;
	import org.apache.iceberg.io.OutputFile;
	import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
	import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList;
	import org.apache.iceberg.relocated.com.google.common.collect.Lists;
	import org.apache.iceberg.util.JsonUtil;

	public class TableMetadataParser {

	public enum Codec {
	NONE(""),
	GZIP(".gz");

	private final String extension;

	Codec(String extension) {
	this.extension = extension;
	}

	public static Codec fromName(String codecName) {
	Preconditions.checkArgument(codecName != null, "Codec name is null");
	return Codec.valueOf(codecName.toUpperCase(Locale.ENGLISH));
	}

	public static Codec fromFileName(String fileName) {
	Preconditions.checkArgument(fileName.contains(".metadata.json"),
	"%s is not a valid metadata file", fileName);
	// we have to be backward-compatible with .metadata.json.gz files
	if (fileName.endsWith(".metadata.json.gz")) {
	return Codec.GZIP;
	}
	String fileNameWithoutSuffix = fileName.substring(0, fileName.lastIndexOf(".metadata.json"));
	if (fileNameWithoutSuffix.endsWith(Codec.GZIP.extension)) {
	return Codec.GZIP;
	} else {
	return Codec.NONE;
	}
	}
	}

	private TableMetadataParser() {
	}

	// visible for testing
	static final String FORMAT_VERSION = "format-version";
	static final String TABLE_UUID = "table-uuid";
	static final String LOCATION = "location";
	static final String LAST_SEQUENCE_NUMBER = "last-sequence-number";
	static final String LAST_UPDATED_MILLIS = "last-updated-ms";
	static final String LAST_COLUMN_ID = "last-column-id";
	static final String SCHEMA = "schema";
	static final String PARTITION_SPEC = "partition-spec";
	static final String PARTITION_SPECS = "partition-specs";
	static final String DEFAULT_SPEC_ID = "default-spec-id";
	static final String DEFAULT_SORT_ORDER_ID = "default-sort-order-id";
	static final String SORT_ORDERS = "sort-orders";
	static final String PROPERTIES = "properties";
	static final String CURRENT_SNAPSHOT_ID = "current-snapshot-id";
	static final String SNAPSHOTS = "snapshots";
	static final String SNAPSHOT_ID = "snapshot-id";
	static final String TIMESTAMP_MS = "timestamp-ms";
	static final String SNAPSHOT_LOG = "snapshot-log";
	static final String METADATA_FILE = "metadata-file";
	static final String METADATA_LOG = "metadata-log";

	public static void overwrite(TableMetadata metadata, OutputFile outputFile) {
	internalWrite(metadata, outputFile, true);
	}

	public static void write(TableMetadata metadata, OutputFile outputFile) {
	internalWrite(metadata, outputFile, false);
	}

	public static void internalWrite(
	TableMetadata metadata, OutputFile outputFile, boolean overwrite) {
	boolean isGzip = Codec.fromFileName(outputFile.location()) == Codec.GZIP;
	OutputStream stream = overwrite ? outputFile.createOrOverwrite() : outputFile.create();
	try (OutputStream ou = isGzip ? new GZIPOutputStream(stream) : stream;
	OutputStreamWriter writer = new OutputStreamWriter(ou, StandardCharsets.UTF_8)) {
	JsonGenerator generator = JsonUtil.factory().createGenerator(writer);
	generator.useDefaultPrettyPrinter();
	toJson(metadata, generator);
	generator.flush();
	} catch (IOException e) {
	throw new RuntimeIOException(e, "Failed to write json to file: %s", outputFile);
	}
	}

	public static String getFileExtension(String codecName) {
	return getFileExtension(Codec.fromName(codecName));
	}

	public static String getFileExtension(Codec codec) {
	return codec.extension + ".metadata.json";
	}

	public static String getOldFileExtension(Codec codec) {
	// we have to be backward-compatible with .metadata.json.gz files
	return ".metadata.json" + codec.extension;
	}

	public static String toJson(TableMetadata metadata) {
	try (StringWriter writer = new StringWriter()) {
	JsonGenerator generator = JsonUtil.factory().createGenerator(writer);
	toJson(metadata, generator);
	generator.flush();
	return writer.toString();
	} catch (IOException e) {
	throw new RuntimeIOException(e, "Failed to write json for: %s", metadata);
	}
	}

	private static void toJson(TableMetadata metadata, JsonGenerator generator) throws IOException {
	generator.writeStartObject();

	generator.writeNumberField(FORMAT_VERSION, metadata.formatVersion());
	generator.writeStringField(TABLE_UUID, metadata.uuid());
	generator.writeStringField(LOCATION, metadata.location());
	if (metadata.formatVersion() > 1) {
	generator.writeNumberField(LAST_SEQUENCE_NUMBER, metadata.lastSequenceNumber());
	}
	generator.writeNumberField(LAST_UPDATED_MILLIS, metadata.lastUpdatedMillis());
	generator.writeNumberField(LAST_COLUMN_ID, metadata.lastColumnId());

	generator.writeFieldName(SCHEMA);
	SchemaParser.toJson(metadata.schema(), generator);

	// for older readers, continue writing the default spec as "partition-spec"
	if (metadata.formatVersion() == 1) {
	generator.writeFieldName(PARTITION_SPEC);
	PartitionSpecParser.toJsonFields(metadata.spec(), generator);
	}

	// write the default spec ID and spec list
	generator.writeNumberField(DEFAULT_SPEC_ID, metadata.defaultSpecId());
	generator.writeArrayFieldStart(PARTITION_SPECS);
	for (PartitionSpec spec : metadata.specs()) {
	PartitionSpecParser.toJson(spec, generator);
	}
	generator.writeEndArray();

	generator.writeNumberField(DEFAULT_SORT_ORDER_ID, metadata.defaultSortOrderId());
	generator.writeArrayFieldStart(SORT_ORDERS);
	for (SortOrder sortOrder : metadata.sortOrders()) {
	SortOrderParser.toJson(sortOrder, generator);
	}
	generator.writeEndArray();

	generator.writeObjectFieldStart(PROPERTIES);
	for (Map.Entry<String, String> keyValue : metadata.properties().entrySet()) {
	generator.writeStringField(keyValue.getKey(), keyValue.getValue());
	}
	generator.writeEndObject();

	generator.writeNumberField(CURRENT_SNAPSHOT_ID,
	metadata.currentSnapshot() != null ? metadata.currentSnapshot().snapshotId() : -1);

	generator.writeArrayFieldStart(SNAPSHOTS);
	for (Snapshot snapshot : metadata.snapshots()) {
	SnapshotParser.toJson(snapshot, generator);
	}
	generator.writeEndArray();

	generator.writeArrayFieldStart(SNAPSHOT_LOG);
	for (HistoryEntry logEntry : metadata.snapshotLog()) {
	generator.writeStartObject();
	generator.writeNumberField(TIMESTAMP_MS, logEntry.timestampMillis());
	generator.writeNumberField(SNAPSHOT_ID, logEntry.snapshotId());
	generator.writeEndObject();
	}
	generator.writeEndArray();

	generator.writeArrayFieldStart(METADATA_LOG);
	for (MetadataLogEntry logEntry : metadata.previousFiles()) {
	generator.writeStartObject();
	generator.writeNumberField(TIMESTAMP_MS, logEntry.timestampMillis());
	generator.writeStringField(METADATA_FILE, logEntry.file());
	generator.writeEndObject();
	}
	generator.writeEndArray();

	generator.writeEndObject();
	}

	/**
	* @deprecated will be removed in 0.9.0; use read(FileIO, InputFile) instead.
	*/
	@Deprecated
	public static TableMetadata read(TableOperations ops, InputFile file) {
	return read(ops.io(), file);
	}

	public static TableMetadata read(FileIO io, String path) {
	return read(io, io.newInputFile(path));
	}

	public static TableMetadata read(FileIO io, InputFile file) {
	Codec codec = Codec.fromFileName(file.location());
	try (InputStream is = codec == Codec.GZIP ? new GZIPInputStream(file.newStream()) : file.newStream()) {
	return fromJson(io, file, JsonUtil.mapper().readValue(is, JsonNode.class));
	} catch (IOException e) {
	throw new RuntimeIOException(e, "Failed to read file: %s", file);
	}
	}

	static TableMetadata fromJson(FileIO io, InputFile file, JsonNode node) {
	Preconditions.checkArgument(node.isObject(),
	"Cannot parse metadata from a non-object: %s", node);

	int formatVersion = JsonUtil.getInt(FORMAT_VERSION, node);
	Preconditions.checkArgument(formatVersion <= TableMetadata.SUPPORTED_TABLE_FORMAT_VERSION,
	"Cannot read unsupported version %s", formatVersion);

	String uuid = JsonUtil.getStringOrNull(TABLE_UUID, node);
	String location = JsonUtil.getString(LOCATION, node);
	long lastSequenceNumber;
	if (formatVersion > 1) {
	lastSequenceNumber = JsonUtil.getLong(LAST_SEQUENCE_NUMBER, node);
	} else {
	lastSequenceNumber = TableMetadata.INITIAL_SEQUENCE_NUMBER;
	}
	int lastAssignedColumnId = JsonUtil.getInt(LAST_COLUMN_ID, node);
	Schema schema = SchemaParser.fromJson(node.get(SCHEMA));

	JsonNode specArray = node.get(PARTITION_SPECS);
	List<PartitionSpec> specs;
	int defaultSpecId;
	if (specArray != null) {
	Preconditions.checkArgument(specArray.isArray(),
	"Cannot parse partition specs from non-array: %s", specArray);
	// default spec ID is required when the spec array is present
	defaultSpecId = JsonUtil.getInt(DEFAULT_SPEC_ID, node);

	// parse the spec array
	ImmutableList.Builder<PartitionSpec> builder = ImmutableList.builder();
	for (JsonNode spec : specArray) {
	builder.add(PartitionSpecParser.fromJson(schema, spec));
	}
	specs = builder.build();

	} else {
	Preconditions.checkArgument(formatVersion == 1,
	"%s must exist in format v%s", PARTITION_SPECS, formatVersion);
	// partition spec is required for older readers, but is always set to the default if the spec
	// array is set. it is only used to default the spec map is missing, indicating that the
	// table metadata was written by an older writer.
	defaultSpecId = TableMetadata.INITIAL_SPEC_ID;
	specs = ImmutableList.of(PartitionSpecParser.fromJsonFields(
	schema, TableMetadata.INITIAL_SPEC_ID, node.get(PARTITION_SPEC)));
	}

	JsonNode sortOrderArray = node.get(SORT_ORDERS);
	List<SortOrder> sortOrders;
	int defaultSortOrderId;
	if (sortOrderArray != null) {
	defaultSortOrderId = JsonUtil.getInt(DEFAULT_SORT_ORDER_ID, node);
	ImmutableList.Builder<SortOrder> sortOrdersBuilder = ImmutableList.builder();
	for (JsonNode sortOrder : sortOrderArray) {
	sortOrdersBuilder.add(SortOrderParser.fromJson(schema, sortOrder));
	}
	sortOrders = sortOrdersBuilder.build();
	} else {
	Preconditions.checkArgument(formatVersion == 1,
	"%s must exist in format v%s", SORT_ORDERS, formatVersion);
	SortOrder defaultSortOrder = SortOrder.unsorted();
	sortOrders = ImmutableList.of(defaultSortOrder);
	defaultSortOrderId = defaultSortOrder.orderId();
	}

	Map<String, String> properties = JsonUtil.getStringMap(PROPERTIES, node);
	long currentVersionId = JsonUtil.getLong(CURRENT_SNAPSHOT_ID, node);
	long lastUpdatedMillis = JsonUtil.getLong(LAST_UPDATED_MILLIS, node);

	JsonNode snapshotArray = node.get(SNAPSHOTS);
	Preconditions.checkArgument(snapshotArray.isArray(),
	"Cannot parse snapshots from non-array: %s", snapshotArray);

	List<Snapshot> snapshots = Lists.newArrayListWithExpectedSize(snapshotArray.size());
	Iterator<JsonNode> iterator = snapshotArray.elements();
	while (iterator.hasNext()) {
	snapshots.add(SnapshotParser.fromJson(io, iterator.next()));
	}

	ImmutableList.Builder<HistoryEntry> entries = ImmutableList.builder();
	if (node.has(SNAPSHOT_LOG)) {
	Iterator<JsonNode> logIterator = node.get(SNAPSHOT_LOG).elements();
	while (logIterator.hasNext()) {
	JsonNode entryNode = logIterator.next();
	entries.add(new SnapshotLogEntry(
	JsonUtil.getLong(TIMESTAMP_MS, entryNode), JsonUtil.getLong(SNAPSHOT_ID, entryNode)));
	}
	}

	ImmutableList.Builder<MetadataLogEntry> metadataEntries = ImmutableList.builder();
	if (node.has(METADATA_LOG)) {
	Iterator<JsonNode> logIterator = node.get(METADATA_LOG).elements();
	while (logIterator.hasNext()) {
	JsonNode entryNode = logIterator.next();
	metadataEntries.add(new MetadataLogEntry(
	JsonUtil.getLong(TIMESTAMP_MS, entryNode), JsonUtil.getString(METADATA_FILE, entryNode)));
	}
	}

	return new TableMetadata(file, formatVersion, uuid, location,
	lastSequenceNumber, lastUpdatedMillis, lastAssignedColumnId, schema, defaultSpecId, specs,
	defaultSortOrderId, sortOrders, properties, currentVersionId, snapshots, entries.build(),
	metadataEntries.build());
	}
	}