javax.sql.rowset (Java Platform SE 8 )
Keywords: javax.sql.rowset package
Date: 2018-07-01

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# Package javax.sql.rowset

Standard interfaces and base classes for JDBC `RowSet` implementations.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  CachedRowSet | The interface that all standard implementations of `CachedRowSet` must implement.
  FilteredRowSet | The standard interface that all standard implementations of `FilteredRowSet` must implement.
  JdbcRowSet | The standard interface that all standard implementations of `JdbcRowSet` must implement.
  Joinable | 1.0 Background
  JoinRowSet | The `JoinRowSet` interface provides a mechanism for combining related data from different `RowSet` objects into one `JoinRowSet` object, which represents an SQL `JOIN`.
  Predicate | The standard interface that provides the framework for all `FilteredRowSet` objects to describe their filters.
  RowSetFactory | An interface that defines the implementation of a factory that is used to obtain different types of `RowSet` implementations.
  WebRowSet | The standard interface that all implementations of a `WebRowSet` must implement.

- Class Summary
  Class | Description
  --- | ---
  BaseRowSet | An abstract class providing a `RowSet` object with its basic functionality.
  RowSetMetaDataImpl | Provides implementations for the methods that set and get metadata information about a `RowSet` object's columns.
  RowSetProvider | A factory API that enables applications to obtain a `RowSetFactory` implementation that can be used to create different types of `RowSet` implementations.

- Exception Summary
  Exception | Description
  --- | ---
  RowSetWarning | An extension of `SQLException` that provides information about database warnings set on `RowSet` objects.

## Package javax.sql.rowset Description

Standard interfaces and base classes for JDBC `RowSet` implementations. This package contains interfaces and classes that a standard `RowSet` implementation either implements or extends.

## Table of Contents

- 1.0 Package Specification
- 2.0 Standard RowSet Definitions
- 3.0 Implementer's Guide
- 4.0 Related Specifications
- 5.0 Related Documentation

### 1.0 Package Specification

This package specifies five standard JDBC `RowSet` interfaces. All five extend the RowSet interface described in the JDBC 3.0 specification. It is anticipated that additional definitions of more specialized JDBC `RowSet` types will emerge as this technology matures. Future definitions should be specified as subinterfaces using inheritance similar to the way it is used in this specification.

Note: The interface definitions provided in this package form the basis for all compliant JDBC `RowSet` implementations. Vendors and more advanced developers who intend to provide their own compliant `RowSet` implementations should pay particular attention to the assertions detailed in specification interfaces.

### 2.0 Standard RowSet Definitions

- `JdbcRowSet` - A wrapper around a `ResultSet` object that makes it possible to use the result set as a JavaBeans™ component. Thus, a `JdbcRowSet` object can be a Bean that any tool makes available for assembling an application as part of a component based architecture . A `JdbcRowSet` object is a connected `RowSet` object, that is, it must continually maintain its connection to its data source using a JDBC technology-enabled driver ("JDBC driver"). In addition, a `JdbcRowSet` object provides a fully updatable and scrollable tabular data structure as defined in the JDBC 3.0 specification.

- `CachedRowSet`™ - A `CachedRowSet` object is a JavaBeans™ component that is scrollable, updatable, serializable, and generally disconnected from the source of its data. A `CachedRowSet` object typically contains rows from a result set, but it can also contain rows from any file with a tabular format, such as a spreadsheet. `CachedRowSet` implementations must use the `SyncFactory` to manage and obtain pluggable `SyncProvider` objects to provide synchronization between the disconnected `RowSet` object and the originating data source. Typically a `SyncProvider` implementation relies upon a JDBC driver to obtain connectivity to a particular data source. Further details on this mechanism are discussed in the `javax.sql.rowset.spi` package specification.

- `WebRowSet` - A `WebRowSet` object is an extension of `CachedRowSet` that can read and write a `RowSet` object in a well formed XML format. This class calls an `XmlReader` object (an extension of the `RowSetReader` interface) to read a rowset in XML format. It calls an `XmlWriter` object (an extension of the `RowSetWriter` interface) to write a rowset in XML format. The reader and writer required by `WebRowSet` objects are provided by the `SyncFactory` in the form of `SyncProvider` implementations. In order to ensure well formed XML usage, a standard generic XML Schema is defined and published at `http://java.sun.com/xml/ns/jdbc/webrowset.xsd`.

- `FilteredRowSet` - A `FilteredRowSet` object provides filtering functionality in a programmatic and extensible way. There are many instances when a `RowSet` `object` has a need to provide filtering in its contents without sacrificing the disconnected environment, thus saving the expense of having to create a connection to the data source. Solutions to this need vary from providing heavyweight full scale SQL query abilities, to portable components, to more lightweight approaches. A `FilteredRowSet` object consumes an implementation of the `Predicate` interface, which may define a filter at run time. In turn, a `FilteredRowSet` object is tasked with enforcing the set filter for both inbound and outbound read and write operations. That is, all filters can be considered as bi-directional. No standard filters are defined; however, sufficient mechanics are specified to permit any required filter to be implemented.

- `JoinRowSet` - The `JoinRowSet` interface describes a mechanism by which relationships can be established between two or more standard `RowSet` implementations. Any number of `RowSet` objects can be added to a `JoinRowSet` object provided the `RowSet`objects can be related in a SQL `JOIN` like fashion. By definition, the SQL `JOIN` statement is used to combine the data contained in two (or more) relational database tables based upon a common attribute. By establishing and then enforcing column matches, a `JoinRowSet` object establishes relationships between `RowSet` instances without the need to touch the originating data source.

### 3.0 Implementer's Guide

Compliant implementations of JDBC `RowSet` Implementations must follow the assertions described in this specification. In accordance with the terms of the Java Community Process, a Test Compatibility Kit (TCK) can be licensed to ensure compatibility with the specification. The following paragraphs outline a number of starting points for implementers of the standard JDBC `RowSet` definitions. Implementers should also consult the Implementer's Guide in the javax.sql.rowset.spi package for guidelines on `SyncProvider` implementations.

- 3.1 Constructor

  All `RowSet` implementations must provide a no-argument constructor.

- 3.2 Role of the `BaseRowSet` Class

  A compliant JDBC `RowSet` implementation must implement one or more standard interfaces specified in this package and and may extend the `BaseRowSet` abstract class. For example, a `CachedRowSet` implementation must implement the `CachedRowSet` interface and extend the `BaseRowSet` abstract class. The `BaseRowSet` class provides the standard architecture on which all `RowSet` implementations should be built, regardless of whether the `RowSet` objects exist in a connected or disconnected environment. The `BaseRowSet` abstract class provides any `RowSet` implementation with its base functionality, including property manipulation and event notification that is fully compliant with JavaBeans component requirements. As an example, all implementations provided in the reference implementations (contained in the `com.sun.rowset` package) use the `BaseRowSet` class as a basis for their implementations.

  The following table illustrates the features that the `BaseRowSet` abstract class provides.

  > Feature | Details
  > Properties | Provides standard JavaBeans property manipulation mechanisms to allow applications to get and set `RowSet` command and property values. Refer to the documentation of the `javax.sql.RowSet` interface (available in the JDBC 3.0 specification) for more details on the standard `RowSet` properties.
  > Event notification | Provides standard JavaBeans event notifications to registered event listeners. Refer to the documentation of `javax.sql.RowSetEvent` interface (available in the JDBC 3.0 specification) for more details on how to register and handle standard RowSet events generated by compliant implementations.
  > Setters for a RowSet object's command | Provides a complete set of setter methods for setting RowSet command parameters.
  > Streams | Provides fields for storing of stream instances in addition to providing a set of constants for stream type designation.

- 3.3 Connected RowSet Requirements

  The `JdbcRowSet` describes a `RowSet` object that must always be connected to the originating data source. Implementations of the `JdbcRowSet` should ensure that this connection is provided solely by a JDBC driver. Furthermore, `RowSet` objects that are implementations of the `JdbcRowSet` interface and are therefore operating in a connected environment do not use the `SyncFactory` to obtain a `RowSetReader` object or a `RowSetWriter` object. They can safely rely on the JDBC driver to supply their needs by virtue of the presence of an underlying updatable and scrollable `ResultSet` implementation.

- 3.4 Disconnected RowSet Requirements

  A disconnected `RowSet` object, such as a `CachedRowSet` object, should delegate connection management to a `SyncProvider` object provided by the `SyncFactory`. To ensure fully disconnected semantics, all disconnected `RowSet` objects must ensure that the original connection made to the data source to populate the `RowSet` object is closed to permit the garbage collector to recover and release resources. The `SyncProvider` object ensures that the critical JDBC properties are maintained in order to re-establish a connection to the data source when a synchronization is required. A disconnected `RowSet` object should therefore ensure that no extraneous references remain on the `Connection` object.

- 3.5 Role of RowSetMetaDataImpl

  The `RowsetMetaDataImpl` class is a utility class that provides an implementation of the RowSetMetaData interface, supplying standard setter method implementations for metadata for both connected and disconnected `RowSet` objects. All implementations are free to use this standard implementation but are not required to do so.

- 3.6 RowSetWarning Class

  The `RowSetWarning` class provides warnings that can be set on `RowSet` implementations. Similar to SQLWarning objects, `RowSetWarning` objects are silently chained to the object whose method caused the warning to be thrown. All `RowSet` implementations should ensure that this chaining occurs if a warning is generated and also ensure that the warnings are available via the `getRowSetWarnings` method defined in either the `JdbcRowSet` interface or the `CachedRowSet` interface. After a warning has been retrieved with one of the `getRowSetWarnings` methods, the `RowSetWarning` method `getNextWarning` can be called on it to retrieve any warnings that might be chained on it. If a warning is returned, `getNextWarning` can be called on it, and so on until there are no more warnings.

- 3.7 The Joinable Interface

  The `Joinable` interface provides both connected and disconnected `RowSet` objects with the capability to be added to a `JoinRowSet` object in an SQL `JOIN` operation. A `RowSet` object that has implemented the `Joinable` interface can set a match column, retrieve a match column, or unset a match column. A `JoinRowSet` object can then use the `RowSet` object's match column as a basis for adding the `RowSet` object.

- 3.8 The RowSetFactory Interface

  A `RowSetFactory` implementation must be provided.

### 4.0 Related Specifications

- JDBC 3.0 Specification
- XML Schema
- SyncML

### 5.0 Related Documentation

- JDBC RowSet Tutorial

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