com.lancedb.lance

Class OpenDatasetBuilder

java.lang.Object

com.lancedb.lance.OpenDatasetBuilder

public class OpenDatasetBuilder
extends Object

Builder for opening a Dataset.

This builder provides a fluent API for opening datasets either directly from a URI or from a LanceNamespace. When using a namespace, the table location and storage options are automatically fetched.

Example usage with URI:

 Dataset dataset = Dataset.open()
     .uri("s3://bucket/table.lance")
     .readOptions(options)
     .build();
 

Example usage with namespace:

 Dataset dataset = Dataset.open()
     .namespace(myNamespace)
     .tableId(Arrays.asList("my_table"))
     .build();
 

Method Summary

Modifier and Type	Method and Description
OpenDatasetBuilder	allocator(org.apache.arrow.memory.BufferAllocator allocator) Sets the buffer allocator.
Dataset	build() Opens the dataset with the configured parameters.
OpenDatasetBuilder	ignoreNamespaceTableStorageOptions(boolean ignoreNamespaceTableStorageOptions) Sets whether to ignore storage options from the namespace's describe_table().
OpenDatasetBuilder	namespace(com.lancedb.lance.namespace.LanceNamespace namespace) Sets the namespace.
OpenDatasetBuilder	readOptions(ReadOptions options) Sets the read options.
OpenDatasetBuilder	tableId(List<String> tableId) Sets the table identifier.
OpenDatasetBuilder	uri(String uri) Sets the dataset URI.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

allocator

public OpenDatasetBuilder allocator(org.apache.arrow.memory.BufferAllocator allocator)

Sets the buffer allocator.

Parameters:

allocator - Arrow buffer allocator

Returns:

this builder instance

uri

public OpenDatasetBuilder uri(String uri)

Sets the dataset URI.

Either uri() or namespace()+tableId() must be specified, but not both.

Parameters:

uri - The dataset URI (e.g., "s3://bucket/table.lance" or "file:///path/to/table.lance")

Returns:

this builder instance

namespace

public OpenDatasetBuilder namespace(com.lancedb.lance.namespace.LanceNamespace namespace)

Sets the namespace.

Must be used together with tableId(). Either uri() or namespace()+tableId() must be specified, but not both.

Parameters:

namespace - The namespace implementation to fetch table info from

Returns:

this builder instance

tableId

public OpenDatasetBuilder tableId(List<String> tableId)

Sets the table identifier.

Must be used together with namespace(). Either uri() or namespace()+tableId() must be specified, but not both.

Parameters:

tableId - The table identifier (e.g., Arrays.asList("my_table"))

Returns:

this builder instance

readOptions

public OpenDatasetBuilder readOptions(ReadOptions options)

Sets the read options.

Parameters:

options - Read options

Returns:

this builder instance

ignoreNamespaceTableStorageOptions

public OpenDatasetBuilder ignoreNamespaceTableStorageOptions(boolean ignoreNamespaceTableStorageOptions)

Sets whether to ignore storage options from the namespace's describe_table().

Parameters:

ignoreNamespaceTableStorageOptions - If true, storage options returned from describe_table() will be ignored (treated as null)

Returns:

this builder instance

build

public Dataset build()

Opens the dataset with the configured parameters.

If a namespace is configured, this automatically fetches the table location and storage options from the namespace via describe_table().

Returns:

Dataset

Throws:

IllegalArgumentException - if required parameters are missing or invalid