/* |
|
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. |
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
|
* |
|
* This code is free software; you can redistribute it and/or modify it |
|
* under the terms of the GNU General Public License version 2 only, as |
|
* published by the Free Software Foundation. Oracle designates this |
|
* particular file as subject to the "Classpath" exception as provided |
|
* by Oracle in the LICENSE file that accompanied this code. |
|
* |
|
* This code is distributed in the hope that it will be useful, but WITHOUT |
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
|
* version 2 for more details (a copy is included in the LICENSE file that |
|
* accompanied this code). |
|
* |
|
* You should have received a copy of the GNU General Public License version |
|
* 2 along with this work; if not, write to the Free Software Foundation, |
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
|
* |
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
* or visit www.oracle.com if you need additional information or have any |
|
* questions. |
|
*/ |
|
package javax.sql.rowset; |
|
import java.sql.SQLException; |
|
/** |
|
* <h3>1.0 Background</h3> |
|
* The <code>Joinable</code> interface provides the methods for getting and |
|
* setting a match column, which is the basis for forming the SQL <code>JOIN</code> |
|
* formed by adding <code>RowSet</code> objects to a <code>JoinRowSet</code> |
|
* object. |
|
* <P> |
|
* Any standard <code>RowSet</code> implementation <b>may</b> implement |
|
* the <code>Joinable</code> interface in order to be |
|
* added to a <code>JoinRowSet</code> object. Implementing this interface gives |
|
* a <code>RowSet</code> object the ability to use <code>Joinable</code> methods, |
|
* which set, retrieve, and get information about match columns. An |
|
* application may add a |
|
* <code>RowSet</code> object that has not implemented the <code>Joinable</code> |
|
* interface to a <code>JoinRowSet</code> object, but to do so it must use one |
|
* of the <code>JoinRowSet.addRowSet</code> methods that takes both a |
|
* <code>RowSet</code> object and a match column or an array of <code>RowSet</code> |
|
* objects and an array of match columns. |
|
* <P> |
|
* To get access to the methods in the <code>Joinable</code> interface, a |
|
* <code>RowSet</code> object implements at least one of the |
|
* five standard <code>RowSet</code> interfaces and also implements the |
|
* <code>Joinable</code> interface. In addition, most <code>RowSet</code> |
|
* objects extend the <code>BaseRowSet</code> class. For example: |
|
* <pre> |
|
* class MyRowSetImpl extends BaseRowSet implements CachedRowSet, Joinable { |
|
* : |
|
* : |
|
* } |
|
* </pre> |
|
* |
|
* <h3>2.0 Usage Guidelines</h3> |
|
* <P> |
|
* The methods in the <code>Joinable</code> interface allow a <code>RowSet</code> object |
|
* to set a match column, retrieve a match column, or unset a match column, which is |
|
* the column upon which an SQL <code>JOIN</code> can be based. |
|
* An instance of a class that implements these methods can be added to a |
|
* <code>JoinRowSet</code> object to allow an SQL <code>JOIN</code> relationship to |
|
* be established. |
|
* |
|
* <pre> |
|
* CachedRowSet crs = new MyRowSetImpl(); |
|
* crs.populate((ResultSet)rs); |
|
* (Joinable)crs.setMatchColumnIndex(1); |
|
* |
|
* JoinRowSet jrs = new JoinRowSetImpl(); |
|
* jrs.addRowSet(crs); |
|
* </pre> |
|
* In the previous example, <i>crs</i> is a <code>CachedRowSet</code> object that |
|
* has implemented the <code>Joinable</code> interface. In the following example, |
|
* <i>crs2</i> has not, so it must supply the match column as an argument to the |
|
* <code>addRowSet</code> method. This example assumes that column 1 is the match |
|
* column. |
|
* <PRE> |
|
* CachedRowSet crs2 = new MyRowSetImpl(); |
|
* crs2.populate((ResultSet)rs); |
|
* |
|
* JoinRowSet jrs2 = new JoinRowSetImpl(); |
|
* jrs2.addRowSet(crs2, 1); |
|
* </PRE> |
|
* <p> |
|
* The <code>JoinRowSet</code> interface makes it possible to get data from one or |
|
* more <code>RowSet</code> objects consolidated into one table without having to incur |
|
* the expense of creating a connection to a database. It is therefore ideally suited |
|
* for use by disconnected <code>RowSet</code> objects. Nevertheless, any |
|
* <code>RowSet</code> object <b>may</b> implement this interface |
|
* regardless of whether it is connected or disconnected. Note that a |
|
* <code>JdbcRowSet</code> object, being always connected to its data source, can |
|
* become part of an SQL <code>JOIN</code> directly without having to become part |
|
* of a <code>JoinRowSet</code> object. |
|
* |
|
* <h3>3.0 Managing Multiple Match Columns</h3> |
|
* The index array passed into the <code>setMatchColumn</code> methods indicates |
|
* how many match columns are being set (the length of the array) in addition to |
|
* which columns will be used for the match. For example: |
|
* <pre> |
|
* int[] i = {1, 2, 4, 7}; // indicates four match columns, with column |
|
* // indexes 1, 2, 4, 7 participating in the JOIN. |
|
* Joinable.setMatchColumn(i); |
|
* </pre> |
|
* Subsequent match columns may be added as follows to a different <code>Joinable</code> |
|
* object (a <code>RowSet</code> object that has implemented the <code>Joinable</code> |
|
* interface). |
|
* <pre> |
|
* int[] w = {3, 2, 5, 3}; |
|
* Joinable2.setMatchColumn(w); |
|
* </pre> |
|
* When an application adds two or more <code>RowSet</code> objects to a |
|
* <code>JoinRowSet</code> object, the order of the indexes in the array is |
|
* particularly important. Each index of |
|
* the array maps directly to the corresponding index of the previously added |
|
* <code>RowSet</code> object. If overlap or underlap occurs, the match column |
|
* data is maintained in the event an additional <code>Joinable</code> RowSet is |
|
* added and needs to relate to the match column data. Therefore, applications |
|
* can set multiple match columns in any order, but |
|
* this order has a direct effect on the outcome of the <code>SQL</code> JOIN. |
|
* <p> |
|
* This assertion applies in exactly the same manner when column names are used |
|
* rather than column indexes to indicate match columns. |
|
* |
|
* @see JoinRowSet |
|
* @author Jonathan Bruce |
|
*/ |
|
public interface Joinable { |
|
/** |
|
* Sets the designated column as the match column for this <code>RowSet</code> |
|
* object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> |
|
* object based on the match column. |
|
* <p> |
|
* Sub-interfaces such as the <code>CachedRowSet</code>™ |
|
* interface define the method <code>CachedRowSet.setKeyColumns</code>, which allows |
|
* primary key semantics to be enforced on specific columns. |
|
* Implementations of the <code>setMatchColumn(int columnIdx)</code> method |
|
* should ensure that the constraints on the key columns are maintained when |
|
* a <code>CachedRowSet</code> object sets a primary key column as a match column. |
|
* |
|
* @param columnIdx an <code>int</code> identifying the index of the column to be |
|
* set as the match column |
|
* @throws SQLException if an invalid column index is set |
|
* @see #setMatchColumn(int[]) |
|
* @see #unsetMatchColumn(int) |
|
* |
|
*/ |
|
public void setMatchColumn(int columnIdx) throws SQLException; |
|
/** |
|
* Sets the designated columns as the match column for this <code>RowSet</code> |
|
* object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> |
|
* object based on the match column. |
|
* |
|
* @param columnIdxes an array of <code>int</code> identifying the indexes of the |
|
* columns to be set as the match columns |
|
* @throws SQLException if an invalid column index is set |
|
* @see #setMatchColumn(int[]) |
|
* @see #unsetMatchColumn(int[]) |
|
*/ |
|
public void setMatchColumn(int[] columnIdxes) throws SQLException; |
|
/** |
|
* Sets the designated column as the match column for this <code>RowSet</code> |
|
* object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> |
|
* object based on the match column. |
|
* <p> |
|
* Subinterfaces such as the <code>CachedRowSet</code> interface define |
|
* the method <code>CachedRowSet.setKeyColumns</code>, which allows |
|
* primary key semantics to be enforced on specific columns. |
|
* Implementations of the <code>setMatchColumn(String columnIdx)</code> method |
|
* should ensure that the constraints on the key columns are maintained when |
|
* a <code>CachedRowSet</code> object sets a primary key column as a match column. |
|
* |
|
* @param columnName a <code>String</code> object giving the name of the column |
|
* to be set as the match column |
|
* @throws SQLException if an invalid column name is set, the column name |
|
* is a null, or the column name is an empty string |
|
* @see #unsetMatchColumn |
|
* @see #setMatchColumn(int[]) |
|
*/ |
|
public void setMatchColumn(String columnName) throws SQLException; |
|
/** |
|
* Sets the designated columns as the match column for this <code>RowSet</code> |
|
* object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> |
|
* object based on the match column. |
|
* |
|
* @param columnNames an array of <code>String</code> objects giving the names |
|
* of the column to be set as the match columns |
|
* @throws SQLException if an invalid column name is set, the column name |
|
* is a null, or the column name is an empty string |
|
* @see #unsetMatchColumn |
|
* @see #setMatchColumn(int[]) |
|
*/ |
|
public void setMatchColumn(String[] columnNames) throws SQLException; |
|
/** |
|
* Retrieves the indexes of the match columns that were set for this |
|
* <code>RowSet</code> object with the method |
|
* <code>setMatchColumn(int[] columnIdxes)</code>. |
|
* |
|
* @return an <code>int</code> array identifying the indexes of the columns |
|
* that were set as the match columns for this <code>RowSet</code> object |
|
* @throws SQLException if no match column has been set |
|
* @see #setMatchColumn |
|
* @see #unsetMatchColumn |
|
*/ |
|
public int[] getMatchColumnIndexes() throws SQLException; |
|
/** |
|
* Retrieves the names of the match columns that were set for this |
|
* <code>RowSet</code> object with the method |
|
* <code>setMatchColumn(String [] columnNames)</code>. |
|
* |
|
* @return an array of <code>String</code> objects giving the names of the columns |
|
* set as the match columns for this <code>RowSet</code> object |
|
* @throws SQLException if no match column has been set |
|
* @see #setMatchColumn |
|
* @see #unsetMatchColumn |
|
* |
|
*/ |
|
public String[] getMatchColumnNames() throws SQLException; |
|
/** |
|
* Unsets the designated column as the match column for this <code>RowSet</code> |
|
* object. |
|
* <P> |
|
* <code>RowSet</code> objects that implement the <code>Joinable</code> interface |
|
* must ensure that a key-like constraint continues to be enforced until the |
|
* method <code>CachedRowSet.unsetKeyColumns</code> has been called on the |
|
* designated column. |
|
* |
|
* @param columnIdx an <code>int</code> that identifies the index of the column |
|
* that is to be unset as a match column |
|
* @throws SQLException if an invalid column index is designated or if |
|
* the designated column was not previously set as a match |
|
* column |
|
* @see #setMatchColumn |
|
*/ |
|
public void unsetMatchColumn(int columnIdx) throws SQLException; |
|
/** |
|
* Unsets the designated columns as the match column for this <code>RowSet</code> |
|
* object. |
|
* |
|
* @param columnIdxes an array of <code>int</code> that identifies the indexes |
|
* of the columns that are to be unset as match columns |
|
* @throws SQLException if an invalid column index is designated or if |
|
* the designated column was not previously set as a match |
|
* column |
|
* @see #setMatchColumn |
|
*/ |
|
public void unsetMatchColumn(int[] columnIdxes) throws SQLException; |
|
/** |
|
* Unsets the designated column as the match column for this <code>RowSet</code> |
|
* object. |
|
* <P> |
|
* <code>RowSet</code> objects that implement the <code>Joinable</code> interface |
|
* must ensure that a key-like constraint continues to be enforced until the |
|
* method <code>CachedRowSet.unsetKeyColumns</code> has been called on the |
|
* designated column. |
|
* |
|
* @param columnName a <code>String</code> object giving the name of the column |
|
* that is to be unset as a match column |
|
* @throws SQLException if an invalid column name is designated or |
|
* the designated column was not previously set as a match |
|
* column |
|
* @see #setMatchColumn |
|
*/ |
|
public void unsetMatchColumn(String columnName) throws SQLException; |
|
/** |
|
* Unsets the designated columns as the match columns for this <code>RowSet</code> |
|
* object. |
|
* |
|
* @param columnName an array of <code>String</code> objects giving the names of |
|
* the columns that are to be unset as the match columns |
|
* @throws SQLException if an invalid column name is designated or the |
|
* designated column was not previously set as a match column |
|
* @see #setMatchColumn |
|
*/ |
|
public void unsetMatchColumn(String[] columnName) throws SQLException; |
|
} |