org.apache.commons.beanutils
Class RowSetDynaClass

java.lang.Object
  org.apache.commons.beanutils.RowSetDynaClass

All Implemented Interfaces:

Serializable, DynaClass

public class RowSetDynaClass
extends Object
implements DynaClass, Serializable

Implementation of DynaClass that creates an in-memory collection of DynaBeans representing the results of an SQL query. Once the DynaClass instance has been created, the JDBC ResultSet and Statement on which it is based can be closed, and the underlying Connection can be returned to its connection pool (if you are using one).

The normal usage pattern is something like:

   Connection conn = ...;  // Acquire connection from pool
   Statement stmt = conn.createStatement();
   ResultSet rs = stmt.executeQuery("SELECT ...");
   RowSetDynaClass rsdc = new RowSetDynaClass(rs);
   rs.close();
   stmt.close();
   ...;                    // Return connection to pool
   List rows = rsdc.getRows();
   ...;                   // Process the rows as desired
 

Each column in the result set will be represented as a DynaBean property of the corresponding name (optionally forced to lower case for portability). There will be one DynaBean in the List returned by getRows() for each row in the original ResultSet.

In general, instances of RowSetDynaClass can be serialized and deserialized, which will automatically include the list of DynaBeans representing the data content. The only exception to this rule would be when the underlying property values that were copied from the ResultSet originally cannot themselves be serialized. Therefore, a RowSetDynaClass makes a very convenient mechanism for transporting data sets to remote Java-based application components.

Version:

$Revision: 556233 $ $Date: 2007-07-14 07:37:06 +0100 (Sat, 14 Jul 2007) $

Author:

Craig R. McClanahan

See Also:

Serialized Form

Field Summary

protected int	limit Limits the size of the returned list.
protected boolean	lowerCase Flag defining whether column names should be lower cased when converted to property names.
protected DynaProperty[]	properties The set of dynamic properties that are part of this DynaClass.
protected Map	propertiesMap The set of dynamic properties that are part of this DynaClass, keyed by the property name.
protected List	rows The list of DynaBeans representing the contents of the original ResultSet on which this RowSetDynaClass was based.

Constructor Summary

RowSetDynaClass(ResultSet resultSet)
Construct a new RowSetDynaClass for the specified ResultSet.

RowSetDynaClass(ResultSet resultSet, boolean lowerCase)
Construct a new RowSetDynaClass for the specified ResultSet.

RowSetDynaClass(ResultSet resultSet, boolean lowerCase, int limit)
Construct a new RowSetDynaClass for the specified ResultSet.

RowSetDynaClass(ResultSet resultSet, int limit)
Construct a new RowSetDynaClass for the specified ResultSet.

Method Summary

protected void	copy(ResultSet resultSet) Copy the column values for each row in the specified ResultSet into a newly created DynaBean, and add this bean to the list of DynaBeans that will later by returned by a call to getRows().
protected DynaBean	createDynaBean() Create and return a new DynaBean instance to be used for representing a row in the underlying result set.
protected DynaProperty	createDynaProperty(ResultSetMetaData metadata, int i) Factory method to create a new DynaProperty for the given index into the result set metadata.
protected String	getColumnName(String name) Get the table column name for the specified property name.
DynaProperty[]	getDynaProperties() Return an array of ProperyDescriptors for the properties currently defined in this DynaClass.
DynaProperty	getDynaProperty(String name) Return a property descriptor for the specified property, if it exists; otherwise, return null.
String	getName() Return the name of this DynaClass (analogous to the getName() method of java.lang.ClassDynaClass implementation class to support different dynamic classes, with different sets of properties.
protected Object	getObject(ResultSet resultSet, String name) Get a column value from a ResultSet for the specified name.
List	getRows() Return a List containing the DynaBeans that represent the contents of each Row from the ResultSet that was the basis of this RowSetDynaClass instance.
protected void	introspect(ResultSet resultSet) Introspect the metadata associated with our result set, and populate the properties and propertiesMap instance variables.
protected Class	loadClass(String className) Loads and returns the Class of the given name.
DynaBean	newInstance() Instantiate and return a new DynaBean instance, associated with this DynaClass.
void	setUseColumnLabel(boolean useColumnLabel) Set whether the column label or name should be used for the property name.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.beanutils.DynaClass

getDynaProperties, getDynaProperty, getName, newInstance

Field Detail

limit

protected int limit

Limits the size of the returned list. The call to getRows() will return at most limit number of rows. If less than or equal to 0, does not limit the size of the result.

rows

protected List rows

The list of DynaBeans representing the contents of the original ResultSet on which this RowSetDynaClass was based.

lowerCase

protected boolean lowerCase

Flag defining whether column names should be lower cased when converted to property names.

properties

protected DynaProperty[] properties

The set of dynamic properties that are part of this DynaClass.

propertiesMap

protected Map propertiesMap

The set of dynamic properties that are part of this DynaClass, keyed by the property name. Individual descriptor instances will be the same instances as those in the properties list.

Constructor Detail

RowSetDynaClass

public RowSetDynaClass(ResultSet resultSet)
                throws SQLException

Construct a new RowSetDynaClass for the specified ResultSet. The property names corresponding to column names in the result set will be lower cased.

Parameters:

resultSet - The result set to be wrapped

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

RowSetDynaClass

public RowSetDynaClass(ResultSet resultSet,
                       int limit)
                throws SQLException

Construct a new RowSetDynaClass for the specified ResultSet. The property names corresponding to column names in the result set will be lower cased.

If limit is not less than 0, max limit number of rows will be copied into the list.

Parameters:

resultSet - The result set to be wrapped

limit - The maximum for the size of the result.

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

RowSetDynaClass

public RowSetDynaClass(ResultSet resultSet,
                       boolean lowerCase)
                throws SQLException

Construct a new RowSetDynaClass for the specified ResultSet. The property names corresponding to the column names in the result set will be lower cased or not, depending on the specified lowerCase value.

If limit is not less than 0, max limit number of rows will be copied into the resultset.

Parameters:

resultSet - The result set to be wrapped

lowerCase - Should property names be lower cased?

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

RowSetDynaClass

public RowSetDynaClass(ResultSet resultSet,
                       boolean lowerCase,
                       int limit)
                throws SQLException

Construct a new RowSetDynaClass for the specified ResultSet. The property names corresponding to the column names in the result set will be lower cased or not, depending on the specified lowerCase value.

WARNING - If you specify false for lowerCase, the returned property names will exactly match the column names returned by your JDBC driver. Because different drivers might return column names in different cases, the property names seen by your application will vary depending on which JDBC driver you are using.

Parameters:

resultSet - The result set to be wrapped

lowerCase - Should property names be lower cased?

limit - Maximum limit for the List of DynaBean

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

Method Detail

getRows

public List getRows()

Return a List containing the DynaBeans that represent the contents of each Row from the ResultSet that was the basis of this RowSetDynaClass instance. These DynaBeans are disconnected from the database itself, so there is no problem with modifying the contents of the list, or the values of the properties of these DynaBeans. However, it is the application's responsibility to persist any such changes back to the database, if it so desires.

Returns:

A List of DynaBean instances

copy

protected void copy(ResultSet resultSet)
             throws SQLException

Copy the column values for each row in the specified ResultSet into a newly created DynaBean, and add this bean to the list of DynaBeans that will later by returned by a call to getRows().

Parameters:

resultSet - The ResultSet whose data is to be copied

Throws:

SQLException - if an error is encountered copying the data

createDynaBean

protected DynaBean createDynaBean()

Create and return a new DynaBean instance to be used for representing a row in the underlying result set.

Returns:

A new DynaBean instance

getName

public String getName()

Return the name of this DynaClass (analogous to the getName() method of java.lang.ClassDynaClass implementation class to support different dynamic classes, with different sets of properties.

Specified by:

getName in interface DynaClass

Returns:

the name of the DynaClass

getDynaProperty

public DynaProperty getDynaProperty(String name)

Return a property descriptor for the specified property, if it exists; otherwise, return null.

Specified by:

getDynaProperty in interface DynaClass

Parameters:

name - Name of the dynamic property for which a descriptor is requested

Returns:

The descriptor for the specified property

Throws:

IllegalArgumentException - if no property name is specified

getDynaProperties

public DynaProperty[] getDynaProperties()

Return an array of ProperyDescriptors for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array will be returned.

Specified by:

getDynaProperties in interface DynaClass

Returns:

the set of properties for this DynaClass

newInstance

public DynaBean newInstance()
                     throws IllegalAccessException,
                            InstantiationException

Instantiate and return a new DynaBean instance, associated with this DynaClass. NOTE - This operation is not supported, and throws an exception.

Specified by:

newInstance in interface DynaClass

Returns:

A new DynaBean instance

Throws:

IllegalAccessException - if the Class or the appropriate constructor is not accessible

InstantiationException - if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some other reason

setUseColumnLabel

public void setUseColumnLabel(boolean useColumnLabel)

Set whether the column label or name should be used for the property name.

Parameters:

useColumnLabel - true if the column label should be used, otherwise false

loadClass

protected Class loadClass(String className)
                   throws SQLException

Loads and returns the Class of the given name. By default, a load from the thread context class loader is attempted. If there is no such class loader, the class loader used to load this class will be utilized.

Parameters:

className - The name of the class to load

Returns:

The loaded class

Throws:

SQLException - if an exception was thrown trying to load the specified class

createDynaProperty

protected DynaProperty createDynaProperty(ResultSetMetaData metadata,
                                          int i)
                                   throws SQLException

Factory method to create a new DynaProperty for the given index into the result set metadata.

Parameters:

metadata - is the result set metadata

i - is the column index in the metadata

Returns:

the newly created DynaProperty instance

Throws:

SQLException - If an error occurs accessing the SQL metadata

introspect

protected void introspect(ResultSet resultSet)
                   throws SQLException

Introspect the metadata associated with our result set, and populate the properties and propertiesMap instance variables.

Parameters:

resultSet - The resultSet whose metadata is to be introspected

Throws:

SQLException - if an error is encountered processing the result set metadata

getObject

protected Object getObject(ResultSet resultSet,
                           String name)
                    throws SQLException

Get a column value from a ResultSet for the specified name.

Parameters:

resultSet - The result set

name - The property name

Returns:

The value

Throws:

SQLException - if an error occurs

getColumnName

protected String getColumnName(String name)

Get the table column name for the specified property name.

Parameters:

name - The property name

Returns:

The column name (which can be different if the lowerCase option is used).