/*
Derby - Class org.apache.derby.vti.StringColumnVTI
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.derby.vti;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Date;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Time;
import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import org.apache.derby.iapi.types.HarmonySerialBlob;
import org.apache.derby.iapi.types.HarmonySerialClob;
/**
* <p>
* This is an abstract table function which assumes that all columns are strings and which
* coerces the strings to reasonable values for various getXXX()
* methods. Subclasses must implement the following ResultSet methods:
* </p>
*
* <ul>
* <li>next( )</li>
* <li>close()</li>
* </ul>
*
* <p>
* and the following protected method introduced by this class:
* </p>
*
* <ul>
* <li>getRawColumn( int columnNumber )</li>
* </ul>
*/
public abstract class StringColumnVTI extends VTITemplate
{
///////////////////////////////////////////////////////////////////////////////////
//
// CONSTANTS
//
///////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////
//
// STATE
//
///////////////////////////////////////////////////////////////////////////////////
private String[] _columnNames;
private boolean _lastColumnWasNull;
///////////////////////////////////////////////////////////////////////////////////
//
// StringColumnVTI BEHAVIOR TO BE IMPLEMENTED BY SUBCLASSES
//
///////////////////////////////////////////////////////////////////////////////////
/**
* <p>
* Get the string value of the column in the current row identified by the 1-based columnNumber.
* </p>
*/
protected abstract String getRawColumn( int columnNumber ) throws SQLException;
///////////////////////////////////////////////////////////////////////////////////
//
// CONSTRUCTORS
//
///////////////////////////////////////////////////////////////////////////////////
/**
* <p>
* Build a StringColumnVTI with the given column names
* </p>
*/
public StringColumnVTI( String[] columnNames )
{
_columnNames = columnNames;
}
///////////////////////////////////////////////////////////////////////////////////
//
// ACCESSORS
//
///////////////////////////////////////////////////////////////////////////////////
/**
* <p>
* Get the number of columns.
* </p>
*/
public int getColumnCount() { return _columnNames.length; }
/**
* <p>
* Get name of a column (1-based indexing).
* </p>
*/
public String getColumnName( int columnNumber ) { return _columnNames[ columnNumber - 1 ]; }
///////////////////////////////////////////////////////////////////////////////////
//
// ResultSet BEHAVIOR
//
///////////////////////////////////////////////////////////////////////////////////
/** This method returns null. Derby does not look at the metadata returned by the table function. */
public ResultSetMetaData getMetaData() throws SQLException { return null; }
public boolean wasNull() throws SQLException { return _lastColumnWasNull; }
public int findColumn( String columnName ) throws SQLException
{
int count = _columnNames.length;
for ( int i = 0; i < count; i++ ) { if ( _columnNames[ i ].equals( columnName ) ) { return i+1; } }
throw new SQLException( "Unknown column name." );
}
public String getString(int columnIndex) throws SQLException
{
String columnValue = getRawColumn( columnIndex );
checkNull( columnValue );
return columnValue;
}
public boolean getBoolean(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return false; }
else { return Boolean.valueOf( columnValue ).booleanValue(); }
}
public byte getByte(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return (byte) 0; }
else
{
try {
return Byte.valueOf( columnValue ).byteValue();
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public short getShort(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return (short) 0; }
else
{
try {
return Short.valueOf( columnValue ).shortValue();
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public int getInt(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return 0; }
else
{
try {
return Integer.parseInt( columnValue );
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public long getLong(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return (long) 0; }
else
{
try {
return Long.valueOf( columnValue ).longValue();
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public float getFloat(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return (float) 0; }
else
{
try {
return Float.parseFloat( columnValue );
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public double getDouble(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return (double) 0; }
else
{
try {
return Double.parseDouble( columnValue );
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public BigDecimal getBigDecimal(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else
{
try {
return new BigDecimal( columnValue );
} catch (NumberFormatException e) { throw wrap( e ); }
}
}
public byte[] getBytes(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else
{
try {
return columnValue.getBytes( "UTF-8" );
} catch (Throwable t) { throw new SQLException( t.getMessage() ); }
}
}
public java.sql.Date getDate(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else
{
return new Date( parseDateTime( columnValue ) );
}
}
public java.sql.Time getTime(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else
{
return new Time( parseDateTime( columnValue ) );
}
}
public java.sql.Timestamp getTimestamp(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else
{
return new Timestamp( parseDateTime( columnValue ) );
}
}
public InputStream getAsciiStream(int columnIndex) throws SQLException
{
String columnValue = getString( columnIndex );
return getEncodedStream( columnValue, "US-ASCII" );
}
public java.io.InputStream getBinaryStream(int columnIndex)
throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else { return new ByteArrayInputStream( getBytes( columnIndex ) ); }
}
public Blob getBlob(int columnIndex)
throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
else { return new HarmonySerialBlob( getBytes( columnIndex ) ); }
}
public Clob getClob(int columnIndex)
throws SQLException
{
String columnValue = getString( columnIndex );
if ( columnValue == null ) { return null; }
{ return new HarmonySerialClob( getString( columnIndex ) ); }
}
///////////////////////////////////////////////////////////////////////////////////
//
// MINIONS
//
///////////////////////////////////////////////////////////////////////////////////
/**
* <p>
* Set the wasNull flag based on whether this column value turned out to be null.
* </p>
*/
private void checkNull( String columnValue )
{
_lastColumnWasNull = ( columnValue == null );
}
/**
* <p>
* Wrap an exception in a SQLException.
* </p>
*/
private SQLException wrap( Throwable t )
{
return new SQLException( t.getMessage() );
}
/**
* <p>
* Translate a date/time expression into the corresponding long number of
* milliseconds.
* </p>
*/
private long parseDateTime( String columnValue )
throws SQLException
{
try {
DateFormat df = DateFormat.getDateTimeInstance();
java.util.Date rawDate = df.parse( columnValue );
return rawDate.getTime();
} catch (ParseException e) { throw wrap( e ); }
}
/**
* <p>
* Turn a string into an appropriately encoded ByteArrayInputStream.
* </p>
*/
private InputStream getEncodedStream( String columnValue, String encoding )
throws SQLException
{
if ( columnValue == null ) { return null; }
else
{
try {
byte[] rawBytes = columnValue.getBytes( encoding );
return new ByteArrayInputStream( rawBytes );
} catch (UnsupportedEncodingException e) { throw wrap( e ); }
}
}
}