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Gemini is a web framework created by TechEmpower.
/*******************************************************************************
* Copyright (c) 2018, TechEmpower, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name TechEmpower, Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL TECHEMPOWER, INC. BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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*******************************************************************************/
package com.techempower.data.util;
import java.sql.*;
import gnu.trove.map.*;
/**
* An implementation of TabularColumn that extracts field values from a
* database connector.
*/
public class DatabaseColumn
implements TabularColumn
{
//
// Member variables.
//
private final String displayFieldName;
private final String dbFieldName;
private final String defaultValue;
/**
* labelFields is a lookup table from integer values stored in the database
* and human-readable String values (e.g., user type 2 = "Subscriber").
* This can be provided as either a String[] or an IntegerMap of Strings.
*/
private final Object labelFields;
//
// Member methods.
//
/**
* Constructor.
*
* @param displayName The display name of this column/field.
* @param dbFieldName The name of the field in the database resultset.
* @param defaultValue A default value to use if data is missing or bad.
* @param labelFields an optional lookup table from integer values to
* Strings. This can be either a String[] or IntegerMap of Strings.
* As integers are pulled from the database, values will be replaced
* with the Strings found in this lookup table.
*/
public DatabaseColumn(String displayName, String dbFieldName,
String defaultValue, Object labelFields)
{
this.displayFieldName = displayName;
this.labelFields = labelFields;
this.dbFieldName = dbFieldName;
this.defaultValue = defaultValue;
}
/**
* Constructor.
*
* @param displayName The display name of this column/field.
* @param dbFieldName The name of the field in the database resultset.
* @param defaultValue A default value to use if data is missing or bad.
*/
public DatabaseColumn(String displayName, String dbFieldName,
String defaultValue)
{
this.displayFieldName = displayName;
this.dbFieldName = dbFieldName;
this.defaultValue = defaultValue;
this.labelFields = null;
}
/**
* Get the value for this column from the current resultset row in the
* DatabaseConnector.
*/
@Override
@SuppressWarnings("unchecked")
public String getValue(Object source)
{
try
{
// This particular class only can get values from ResultSets.
if (source instanceof ResultSet)
{
String dbValue;
ResultSet conn = (ResultSet)source;
// If we've been given a set of Strings that are mapped to database
// integers, let's grab the integer and use the mapped String.
if (labelFields != null)
{
if (labelFields instanceof TIntObjectMap)
{
final int dbInt = conn.getInt(dbFieldName);
TIntObjectMap labelFieldsMap = (TIntObjectMap)labelFields;
dbValue = labelFieldsMap.get(dbInt);
if (dbValue == null)
{
dbValue = defaultValue;
}
}
else if (labelFields instanceof TLongObjectMap)
{
final long dbLong = conn.getLong(dbFieldName);
TLongObjectMap labelFieldsMap = (TLongObjectMap)labelFields;
dbValue = labelFieldsMap.get(dbLong);
if (dbValue == null)
{
dbValue = defaultValue;
}
}
else
{
final int dbInt = conn.getInt(dbFieldName);
String[] labelFieldsString = (String[])labelFields;
if ( (dbInt >= 0)
&& (dbInt < labelFieldsString.length)
)
{
dbValue = labelFieldsString[dbInt];
}
else
{
dbValue = defaultValue;
}
}
}
// Otherwise, get the value from the database directly.
else
{
dbValue = conn.getString(dbFieldName);
if (dbValue == null)
{
dbValue = defaultValue;
}
}
return dbValue;
}
}
catch (SQLException exc)
{
// No need to log, use the defaultValue.
}
// If the source is not a Connection or there was a SQLException, return the default value.
return defaultValue;
}
/**
* Return the display name of this column.
*/
@Override
public String getDisplayName()
{
return displayFieldName;
}
} // End DatabaseColumn.