Package org.firebirdsql.jdbc

Class AbstractFieldMetaData

java.lang.Object

org.firebirdsql.jdbc.AbstractFieldMetaData

All Implemented Interfaces:

java.sql.Wrapper

Direct Known Subclasses:

FBParameterMetaData, FBResultSetMetaData

public abstract class AbstractFieldMetaData
extends java.lang.Object
implements java.sql.Wrapper

Base class for FBResultSetMetaData and FBParameterMetaData for methods common to both implementations.

Since:

3.0

Author:

David Jencks, Nickolay Samofatov, Mark Rotteveel

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AbstractFieldMetaData.ExtendedFieldInfo	This class is an old-fashion data structure that stores additional information about fields in a database.
protected static class	AbstractFieldMetaData.FieldKey	This class should be used as a composite key in an internal field mapping structures.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractFieldMetaData(RowDescriptor rowDescriptor, FBConnection connection)

Method Summary

Modifier and Type	Method	Description
protected int	estimateFixedPrecision(int fieldIndex)
protected abstract java.util.Map<AbstractFieldMetaData.FieldKey,AbstractFieldMetaData.ExtendedFieldInfo>	getExtendedFieldInfo(FBConnection connection)	This method retrieves extended information from the system tables in a database.
protected AbstractFieldMetaData.ExtendedFieldInfo	getExtFieldInfo(int columnIndex)
protected java.lang.String	getFieldClassName(int field)
protected int	getFieldCount()	Retrieves the number of fields in the object for which this AbstractFieldMetaData object contains information.
protected FieldDescriptor	getFieldDescriptor(int fieldIndex)	The FieldDescriptor of the field with index fieldIndex.
protected int	getFieldType(int field)
protected java.lang.String	getFieldTypeName(int field)
protected int	getPrecisionInternal(int field)	Retrieves the designated parameter's specified column size.
protected RowDescriptor	getRowDescriptor()
protected int	getScaleInternal(int field)	Retrieves the designated field's number of digits to right of the decimal point.
protected boolean	isSignedInternal(int field)	Retrieves whether values for the designated field can be signed numbers.
boolean	isWrapperFor(java.lang.Class<?> iface)
<T> T	unwrap(java.lang.Class<T> iface)

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractFieldMetaData

protected AbstractFieldMetaData(RowDescriptor rowDescriptor,
                                FBConnection connection)

Method Detail

isWrapperFor

public boolean isWrapperFor(java.lang.Class<?> iface)
                     throws java.sql.SQLException

Specified by:

isWrapperFor in interface java.sql.Wrapper

Throws:

java.sql.SQLException

unwrap

public <T> T unwrap(java.lang.Class<T> iface)
             throws java.sql.SQLException

Specified by:

unwrap in interface java.sql.Wrapper

Throws:

java.sql.SQLException

getRowDescriptor

protected final RowDescriptor getRowDescriptor()

Returns:

The row descriptor.

getFieldCount

protected final int getFieldCount()

Retrieves the number of fields in the object for which this AbstractFieldMetaData object contains information.

Returns:

the number of fields

getFieldDescriptor

protected final FieldDescriptor getFieldDescriptor(int fieldIndex)

The FieldDescriptor of the field with index fieldIndex.

Parameters:

fieldIndex - 1-based index of a field in this metadata object

Returns:

field descriptor

isSignedInternal

protected final boolean isSignedInternal(int field)

Retrieves whether values for the designated field can be signed numbers.

Parameters:

field - the first field is 1, the second is 2, ...

Returns:

true if so; false otherwise

getScaleInternal

protected final int getScaleInternal(int field)

Retrieves the designated field's number of digits to right of the decimal point. 0 is returned for data types where the scale is not applicable.

Parameters:

field - the first field is 1, the second is 2, ...

Returns:

scale

getFieldClassName

protected final java.lang.String getFieldClassName(int field)
                                            throws java.sql.SQLException

Throws:

java.sql.SQLException

getFieldTypeName

protected final java.lang.String getFieldTypeName(int field)

getFieldType

protected int getFieldType(int field)

getPrecisionInternal

protected final int getPrecisionInternal(int field)
                                  throws java.sql.SQLException

Retrieves the designated parameter's specified column size.

The returned value represents the maximum column size for the given parameter. For numeric data, this is the maximum precision. For character data, this is the length in characters. For datetime datatypes, this is the length in characters of the String representation (assuming the maximum allowed precision of the fractional seconds component). For binary data, this is the length in bytes. For the ROWID datatype, this is the length in bytes. 0 is returned for data types where the column size is not applicable.

Parameters:

field - the first field is 1, the second is 2, ...

Returns:

precision

Throws:

java.sql.SQLException - if a database access error occurs

estimateFixedPrecision

protected final int estimateFixedPrecision(int fieldIndex)

getExtFieldInfo

protected final AbstractFieldMetaData.ExtendedFieldInfo getExtFieldInfo(int columnIndex)
                                                                 throws java.sql.SQLException

Throws:

java.sql.SQLException

getExtendedFieldInfo

protected abstract java.util.Map<AbstractFieldMetaData.FieldKey,AbstractFieldMetaData.ExtendedFieldInfo> getExtendedFieldInfo(FBConnection connection)
                                                                                                                             throws java.sql.SQLException

This method retrieves extended information from the system tables in a database. Since this method is expensive, use it with care.

Returns:

mapping between AbstractFieldMetaData.FieldKey instances and AbstractFieldMetaData.ExtendedFieldInfo instances, or an empty Map if the metadata implementation does not support extended info.

Throws:

java.sql.SQLException - if a database error occurs while obtaining extended field information.