Package org.apache.commons.beanutils2.sql

Class ResultSetDynaClass

java.lang.Object
org.apache.commons.beanutils2.sql.ResultSetDynaClass
All Implemented Interfaces:
DynaClass
public class ResultSetDynaClass extends Object

Implements DynaClass for DynaBeans that wrap the java.sql.Row</code> objects of a <code>java.sql.ResultSet. The normal usage pattern is something like: 

   ResultSet rs = ...;
   ResultSetDynaClass rsdc = new ResultSetDynaClass(rs);
   Iterator rows = rsdc.iterator();
   while (rows.hasNext())  {
     DynaBean row = (DynaBean) rows.next();
     ... process this row ...
   }
   rs.close();

Each column in the result set will be represented as a DynaBean property of the corresponding name (optionally forced to lower case for portability).

WARNING - Any DynaBean instance returned by this class, or from the Iterator returned by the iterator() method, is directly linked to the row that the underlying result set is currently positioned at. This has the following implications:

  • Once you retrieve a different DynaBean instance, you should no longer use any previous instance.
  • Changing the position of the underlying result set will change the data that the DynaBean references.
  • Once the underlying result set is closed, the DynaBean instance may no longer be used.

Any database data that you wish to utilize outside the context of the current row of an open result set must be copied. For example, you could use the following code to create standalone copies of the information in a result set: 

   List results = new ArrayList(); // To hold copied list
   ResultSetDynaClass rsdc = ...;
   DynaProperty[] properties = rsdc.getDynaProperties();
   BasicDynaClass bdc =
     new BasicDynaClass("foo", BasicDynaBean.class,
                        rsdc.getDynaProperties());
   Iterator rows = rsdc.iterator();
   while (rows.hasNext()) {
     DynaBean oldRow = (DynaBean) rows.next();
     DynaBean newRow = bdc.newInstance();
     PropertyUtils.copyProperties(newRow, oldRow);
     results.add(newRow);
   }

  • Field Details

    • resultSet

      protected ResultSet resultSet

      The ResultSet we are wrapping.

    • 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<String,DynaProperty> 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 Details

    • ResultSetDynaClass

      public ResultSetDynaClass(ResultSet resultSet) throws SQLException

      Constructs a new ResultSetDynaClass 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

    • ResultSetDynaClass

      public ResultSetDynaClass(ResultSet resultSet, boolean lowerCase) throws SQLException

      Constructs a new ResultSetDynaClass 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?
      Throws:
      NullPointerException - if resultSet is null
      SQLException - if the metadata for this result set cannot be introspected

    • ResultSetDynaClass

      public ResultSetDynaClass(ResultSet resultSet, boolean lowerCase, boolean useColumnLabel) throws SQLException

      Constructs a new ResultSetDynaClass 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?
      useColumnLabel - true if the column label should be used, otherwise false
      Throws:
      NullPointerException - if resultSet is null
      SQLException - if the metadata for this result set cannot be introspected
      Since:
      1.8.3

  • Method Details

    • getObjectFromResultSet

      public Object getObjectFromResultSet(String name) throws SQLException
      Gets a value from the ResultSet for the specified property name.
      Parameters:
      name - The property name
      Returns:
      The value
      Throws:
      SQLException - if an error occurs
      Since:
      1.8.0

    • iterator

      public Iterator<DynaBean> iterator()

      Return an Iterator of DynaBean instances for each row of the wrapped ResultSet, in "forward" order. Unless the underlying result set supports scrolling, this method should be called only once.

      Returns:
      An Iterator of DynaBean instances

    • loadClass

      protected Class<?> loadClass(String className) throws SQLException

      Loads the class of the given name which by default uses the class loader used to load this library. Derivations of this class could implement alternative class loading policies such as using custom ClassLoader or using the Threads's context class loader etc.

      Parameters:
      className - The name of the class to load
      Returns:
      The loaded class
      Throws:
      SQLException - if the class cannot be loaded

    • 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

    • getColumnName

      protected String getColumnName(String name)
      Gets 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).

    • getDynaProperties

      public DynaProperty[] getDynaProperties()

      Gets an array of PropertyDescriptor 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

    • getDynaProperty

      public DynaProperty getDynaProperty(String name)

      Gets 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

    • getName

      public String getName()

      Gets the name of this DynaClass (analogous to the getName()</code> method of <code>java.lang.Class, which allows the same DynaClass implementation class to support different dynamic classes, with different sets of properties.

      Specified by:
      getName in interface DynaClass
      Returns:
      the name of the DynaClass

    • getObject

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

    • introspect

      protected void introspect(ResultSet resultSet) throws SQLException

      Introspect the metadata associated with our result set, and populate the properties</code> and <code>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

    • 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)
      Sets 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