Introduction
I recently recognized the importance of Design Patterns so started to change my non-design-pattern-code to design-pattern-code. In this part, I introduce an example that adapts the Template Method Design Pattern, but I don't know whether this is good or bad. I look forward to listening to your opinions.
Background
The Template Method Design Pattern defines the program skeleton of an algorithm on a Template Method of an abstract class. Child classes instantiate this algorithm by implementing their own logic on the skeleton that is an abstract method provided by the abstract class.
Coding without considering a Design Pattern
The fuction InitCommonVariables()
initializes two ArrayList
s using filtering from the DataTable
(dtMSTDLDTM
) and repeats this work for another DataTable
(dtMEVENT
). You will figure out that the two initialization processes have the same algorithm.
private void InitCommonVariables()
{
currentActivity = (Progress.Model.ProgressActivity)this.Activity;
if (currentActivity.BNodeLevel == (int)ActivityNodeLevel.Kojun)
{
dtMSTDLDTM = ((ProgressGanttModel)(currentActivity.GanttModel)).dtMSTDLDTM;
if (dtMSTDLDTM.Rows.Count > 0)
{
System.Data.DataColumn[] primaryKey = new System.Data.DataColumn[1];
primaryKey[0] = dtMSTDLDTM.Columns[0];
dtMSTDLDTM.PrimaryKey = primaryKey;
listWrkID = new ArrayList();
listWrkNM = new ArrayList();
String filter = "";
if (initParams.scheduleType == EnumScheduleType.Mschedule)
{
filter = "SCH_TYP<>2";
}
else if (initParams.scheduleType == EnumScheduleType.Sschedule)
{
filter = "SCH_TYP=2";
}
filter = "(" + filter + ") AND (DEL_FLG<>1)";
foreach (System.Data.DataRow row in dtMSTDLDTM.Select(filter))
{
listWrkID.Add(row["WRK_ID"].ToString());
listWrkNM.Add(row["WRK_NM"].ToString());
}
}
if (dtMSTDLDTM.Columns.Count == 0)
{
System.Data.DataColumn wrkIDColumn = new System.Data.DataColumn("WRK_ID");
System.Data.DataColumn wrkNMColumn = new System.Data.DataColumn("WRK_NM");
dtMSTDLDTM.Columns.Add(wrkIDColumn);
dtMSTDLDTM.Columns.Add(wrkNMColumn);
}
if (currentActivity.BEventFlg == 1)
{
dtMEVENT = ((ProgressGanttModel)(currentActivity.GanttModel)).dtMEVENT;
if (dtMEVENT.Rows.Count > 0)
{
primaryKey = new System.Data.DataColumn[1];
primaryKey[0] = dtMEVENT.Columns[0];
dtMEVENT.PrimaryKey = primaryKey;
listEventID = new ArrayList();
listEventNM = new ArrayList();
foreach (System.Data.DataRow row in dtMEVENT.Rows)
{
listEventID.Add(row["EVENT_ID"].ToString());
listEventNM.Add(row["EVENT_NM"].ToString());
}
}
if (dtMEVENT.Columns.Count == 0)
{
System.Data.DataColumn eventIDColumn = new System.Data.DataColumn("EVENT_ID");
System.Data.DataColumn eventNMColumn = new System.Data.DataColumn("EVENT_NM");
dtMEVENT.Columns.Add(eventIDColumn);
dtMEVENT.Columns.Add(eventNMColumn);
}
}
}
}
Using two ArrayList
s, I initialize a ComboBox
:
private void SetItemsonKojunNameCombo(ComboBox comboBox, System.Data.DataTable dataSource)
{
comboBox.DisplayMember = "WRK_NM";
comboBox.ValueMember = "WRK_ID";
System.Data.DataTable dataTable = getMStdLdTmFilterTbl(dataSource);
comboBox.DataSource = dataTable;
if (dataTable.Rows.Count > 0)
{
int currentItemIndex = listWrkID.IndexOf(currentActivity.BWrkId);
if (currentItemIndex >= 0)
{
System.Data.DataTable displayTable = dataTable.Copy();
displayTable.Rows[currentItemIndex]["WRK_NM"] = currentActivity.Name;
comboBox.DataSource = displayTable;
comboBox.SelectedIndex = currentItemIndex;
}
else
{
System.Data.DataTable displayTable = dataTable.Copy();
System.Data.DataRow row = displayTable.NewRow();
if (currentActivity.BWrkId != null)
{
row["WRK_ID"] = currentActivity.BWrkId;
}
else
{
row["WRK_ID"] = -1;
}
if (currentActivity.BWrkName != null)
{
row["WRK_NM"] = currentActivity.BWrkName;
}
else
{
row["WRK_NM"] = "";
}
displayTable.Rows.InsertAt(row, 0);
comboBox.DataSource = displayTable;
comboBox.SelectedIndex = 0;
}
}
else
{
System.Data.DataTable displayTable = dataTable.Copy();
displayTable.Clear();
if (currentActivity.BWrkId != null)
{
System.Data.DataRow row = displayTable.NewRow();
row["WRK_ID"] = currentActivity.BWrkId;
row["WRK_NM"] = currentActivity.BWrkName;
displayTable.Rows.Add(row);
}
comboBox.DataSource = displayTable;
if (currentActivity.BWrkId != null)
{
comboBox.SelectedIndex = 0;
}
}
}
private void SetItemsonEventNameCombo(ComboBox comboBox, System.Data.DataTable dataSource)
{
comboBox.DisplayMember = "EVENT_NM";
comboBox.ValueMember = "EVENT_ID";
comboBox.DataSource = dataSource;
if (dataSource.Rows.Count > 0)
{
int currentItemIndex = -1;
if (currentActivity.Name != null)
{
currentItemIndex = listEventNM.IndexOf(currentActivity.Name);
}
if (currentItemIndex >= 0)
{
System.Data.DataTable displayTable = dataSource.Copy();
comboBox.DataSource = displayTable;
comboBox.SelectedIndex = currentItemIndex;
}
}
comboBox.DropDownStyle = ComboBoxStyle.DropDownList;
}
Lastly, I save the selected item and the selected value from the ComboBox
:
private void SaveKojunWorkNMandID()
{
currentActivity.BWrkName = kojunNameCombo.Text;
currentActivity.Name = kojunNameCombo.Text;
if (listWrkID.Contains(kojunNameCombo.SelectedValue))
{
int selectedIndex = listWrkID.IndexOf(kojunNameCombo.SelectedValue);
if (selectedIndex >= 0)
{
if (kojunNameCombo.Text == (string)listWrkNM[selectedIndex])
{
currentActivity.BWrkId = (string)kojunNameCombo.SelectedValue;
}
else
{
currentActivity.BWrkId = "";
}
}
else
{
currentActivity.BWrkId = "";
}
}
else
{
currentActivity.BWrkId = "";
}
}
private void SetEventNMandID()
{
currentActivity.BWrkName = eventNameCombo.Text;
currentActivity.Name = eventNameCombo.Text;
if ((eventNameCombo.SelectedIndex >= 0) &&
(eventNameCombo.SelectedIndex < listEventID.Count))
{
currentActivity.BWrkId = (string)listEventID[eventNameCombo.SelectedIndex];
}
}
Recoding using a Design Pattern
I designed two template methods: InitializeList()
and InitializeItemsOnComboBox()
, and two child classes: ConcreteTableToKojunComboBox
and ConcreteTableToEventComboBox
.
class PADUtil
{
public abstract class AbstractTableToComboBox
{
public abstract void CreateList();
public abstract bool CheckTable();
public abstract bool HasColumnsandRows();
public abstract void SetFilter();
public void InitializeList()
{
SetFilter();
if (CheckTable() && HasColumnsandRows())
{
CreateList();
}
}
public abstract void SetComboBoxMember();
public abstract int HasCurrentItem();
public abstract void JustSetCurrentItem(int index);
public abstract void AddandSetCurrentItem();
public void InitializeItemsOnComboBox()
{
SetComboBoxMember();
int index = HasCurrentItem();
if (index >= 0)
{
JustSetCurrentItem(index);
}
else
{
AddandSetCurrentItem();
}
}
public abstract object GetValueOfCurrentItem(object dispaly);
}
public class ConcreteTableToKojunComboBox : AbstractTableToComboBox
{
private DataTable table;
private ArrayList displayList;
private ArrayList valueList;
private string filter = "";
private string displayMember = "";
private string valueMember = "";
private EnumScheduleType scheduleType;
private ComboBox comboBox;
public struct CurrentItem
{
public object display;
public object value;
}
public CurrentItem currentItem = new CurrentItem();
public ConcreteTableToKojunComboBox(DataTable table, ArrayList displayList,
ArrayList valueList, DataColumn[] primaryKey, string displayMember,
string valueMember, EnumScheduleType scheduleType, ComboBox comboBox)
{
this.table = table;
this.displayList = displayList;
this.valueList = valueList;
this.table.PrimaryKey = primaryKey;
this.displayMember = displayMember;
this.valueMember = valueMember;
this.scheduleType = scheduleType;
this.comboBox = comboBox;
}
public override bool CheckTable()
{
if (table == null || displayList == null || valueList == null ||
displayMember == "" || valueMember == "")
{
return false;
}
return true;
}
public override bool HasColumnsandRows()
{
if (table.Columns.Count == 0)
{
table.Columns.Add(new DataColumn(displayMember));
table.Columns.Add(new DataColumn(valueMember));
return false;
}
else if (table.Rows.Count == 0)
{
return false;
}
return true;
}
public override void SetFilter()
{
if (table.Columns.Contains("SCH_TYP") && table.Columns.Contains("DEL_FLG"))
{
if (scheduleType == EnumScheduleType.Mschedule)
{
filter = "SCH_TYP<>2";
}
else if (scheduleType == EnumScheduleType.Sschedule)
{
filter = "SCH_TYP=2";
}
filter = "(" + filter + ") AND (DEL_FLG<>1)";
}
}
public override void CreateList()
{
foreach (System.Data.DataRow row in table.Select(filter))
{
displayList.Add(row[displayMember].ToString());
valueList.Add(row[valueMember].ToString());
}
}
public override void SetComboBoxMember()
{
this.comboBox.DisplayMember = this.displayMember;
this.comboBox.ValueMember = this.valueMember;
}
public override int HasCurrentItem()
{
if((currentItem.value == null))
{
return -1;
}
int index = -1;
foreach (System.Data.DataRow row in table.Select(filter))
{
index++;
if (row[valueMember].ToString() == currentItem.value.ToString())
{
return index;
}
}
return -1;
}
private DataTable MakeComboBoxDataSource()
{
DataTable displayTable = table.Copy();
displayTable.Clear();
foreach (DataRow row in table.Select(filter))
{
DataRow newRow = displayTable.NewRow();
foreach (DataColumn col in table.Columns)
{
newRow[col.ColumnName] = row[col.ColumnName];
}
displayTable.Rows.Add(newRow);
}
return displayTable;
}
public override void AddandSetCurrentItem()
{
DataTable displayTable = MakeComboBoxDataSource();
System.Data.DataRow currentItemRow = displayTable.NewRow();
currentItemRow[displayMember] = currentItem.display;
if (currentItem.value != null)
{
currentItemRow[valueMember] = currentItem.value;
}
else
{
currentItemRow[valueMember] = "";
}
displayTable.Rows.Add(currentItemRow);
comboBox.DataSource = displayTable;
if (comboBox.Items.Count > 0)
{
comboBox.SelectedIndex = comboBox.Items.Count - 1;
}
}
public override void JustSetCurrentItem(int index)
{
DataTable displayTable = MakeComboBoxDataSource();
displayTable.Rows[index][displayMember] = currentItem.display;
comboBox.DataSource = displayTable;
if ((comboBox.Items.Count > 0) && (index >= 0) && (index < comboBox.Items.Count))
{
comboBox.SelectedIndex = index;
}
}
public override object GetValueOfCurrentItem(object dispaly)
{
currentItem.display = dispaly;
foreach (DataRow row in table.Select(filter))
{
if (row[displayMember] == dispaly)
{
currentItem.value = row[valueMember];
return currentItem.value;
}
}
currentItem.value = "";
return currentItem.value;
}
}
public class ConcreteTableToEventComboBox : AbstractTableToComboBox
{
private DataTable table;
private ArrayList displayList;
private ArrayList valueList;
private string filter = "";
private string displayMember = "";
private string valueMember = "";
private EnumScheduleType scheduleType;
private ComboBox comboBox;
public struct CurrentItem
{
public object display;
public object value;
}
public CurrentItem currentItem = new CurrentItem();
public ConcreteTableToEventComboBox(DataTable table, ArrayList displayList,
ArrayList valueList, DataColumn[] primaryKey, string displayMember,
string valueMember, EnumScheduleType scheduleType, ComboBox comboBox)
{
this.table = table;
this.displayList = displayList;
this.valueList = valueList;
this.table.PrimaryKey = primaryKey;
this.displayMember = displayMember;
this.valueMember = valueMember;
this.scheduleType = scheduleType;
this.comboBox = comboBox;
}
public override bool CheckTable()
{
if (table == null || displayList == null || valueList == null ||
displayMember == "" || valueMember == "")
{
return false;
}
return true;
}
public override bool HasColumnsandRows()
{
if (table.Columns.Count == 0)
{
table.Columns.Add(new DataColumn(displayMember));
table.Columns.Add(new DataColumn(valueMember));
return false;
}
else if (table.Rows.Count == 0)
{
return false;
}
return true;
}
public override void SetFilter()
{
}
public override void CreateList()
{
foreach (System.Data.DataRow row in table.Select(filter))
{
displayList.Add(row[displayMember].ToString());
valueList.Add(row[valueMember].ToString());
}
}
public override void SetComboBoxMember()
{
this.comboBox.DisplayMember = this.displayMember;
this.comboBox.ValueMember = this.valueMember;
}
public override int HasCurrentItem()
{
if ((currentItem.value == null))
{
return -1;
}
int index = -1;
foreach (System.Data.DataRow row in table.Select(filter))
{
index++;
if (row[valueMember].ToString() == currentItem.value.ToString())
{
return index;
}
}
return -1;
}
private DataTable MakeComboBoxDataSource()
{
DataTable displayTable = table.Copy();
displayTable.Clear();
foreach (DataRow row in table.Select(filter))
{
DataRow newRow = displayTable.NewRow();
foreach (DataColumn col in table.Columns)
{
newRow[col.ColumnName] = row[col.ColumnName];
}
displayTable.Rows.Add(newRow);
}
return displayTable;
}
public override void AddandSetCurrentItem()
{
DataTable displayTable = MakeComboBoxDataSource();
System.Data.DataRow currentItemRow = displayTable.NewRow();
currentItemRow[displayMember] = currentItem.display;
if (currentItem.value != null)
{
currentItemRow[valueMember] = currentItem.value;
}
else
{
currentItemRow[valueMember] = -1;
}
displayTable.Rows.Add(currentItemRow);
comboBox.DataSource = displayTable;
if (comboBox.Items.Count > 0)
{
comboBox.SelectedIndex = comboBox.Items.Count - 1;
}
comboBox.DropDownStyle = ComboBoxStyle.DropDownList;
}
public override void JustSetCurrentItem(int index)
{
DataTable displayTable = MakeComboBoxDataSource();
comboBox.DataSource = displayTable;
if ((comboBox.Items.Count > 0) && (index >= 0) && (index < comboBox.Items.Count))
{
comboBox.SelectedIndex = index;
}
comboBox.DropDownStyle = ComboBoxStyle.DropDownList;
}
public override object GetValueOfCurrentItem(object dispaly)
{
currentItem.display = dispaly;
foreach (DataRow row in table.Select(filter))
{
if (row[displayMember] == dispaly)
{
currentItem.value = row[valueMember];
return currentItem.value;
}
}
currentItem.value = "";
return currentItem.value;
}
}
}
PADUtil.AbstractTableToComboBox MStdLdtmToKojunComboBox;
PADUtil.ConcreteTableToEventComboBox MEventToEventComboBox;
private void InitCommonVariables()
{
currentActivity = (Progress.Model.ProgressActivity)this.Activity;
if (currentActivity.BNodeLevel == (int)ActivityNodeLevel.Kojun)
{
dtMSTDLDTM = ((ProgressGanttModel)(currentActivity.GanttModel)).dtMSTDLDTM;
listWrkID = new ArrayList();
listWrkNM = new ArrayList();
System.Data.DataColumn[] primaryKey = new System.Data.DataColumn[1];
primaryKey[0] = dtMSTDLDTM.Columns[0];
string displayMember = "WRK_NM";
string vlaueMember = "WRK_ID";
MStdLdtmToKojunComboBox = new PADUtil.ConcreteTableToKojunComboBox(dtMSTDLDTM,
listWrkNM, listWrkID, primaryKey, displayMember,
vlaueMember, initParams.scheduleType, kojunNameCombo);
MStdLdtmToKojunComboBox.InitializeList();
if (currentActivity.BEventFlg == 1)
{
dtMEVENT = ((ProgressGanttModel)(currentActivity.GanttModel)).dtMEVENT;
listEventID = new ArrayList();
listEventNM = new ArrayList();
primaryKey = new System.Data.DataColumn[1];
primaryKey[0] = dtMEVENT.Columns[0];
displayMember = "EVENT_NM";
vlaueMember = "EVENT_ID";
MEventToEventComboBox = new PADUtil.ConcreteTableToEventComboBox(dtMEVENT,
listEventNM, listEventID, primaryKey,
displayMember, vlaueMember,
initParams.scheduleType, eventNameCombo);
MEventToEventComboBox.InitializeList();
}
}
}
private void SetItemsonKojunNameCombo()
{
((PADUtil.ConcreteTableToKojunComboBox)
MStdLdtmToKojunComboBox).currentItem.display = currentActivity.BWrkName;
((PADUtil.ConcreteTableToKojunComboBox)
MStdLdtmToKojunComboBox).currentItem.value = currentActivity.BWrkId;
MStdLdtmToKojunComboBox.InitializeItemsOnComboBox();
}
private void SetItemsonEventNameCombo()
{
((PADUtil.ConcreteTableToEventComboBox)
MEventToEventComboBox).currentItem.display = currentActivity.BWrkName;
((PADUtil.ConcreteTableToEventComboBox)
MEventToEventComboBox).currentItem.value = currentActivity.BWrkId;
MEventToEventComboBox.InitializeItemsOnComboBox();
}
private void SaveKojunWorkNMandID()
{
currentActivity.BWrkName = kojunNameCombo.Text;
currentActivity.Name = kojunNameCombo.Text;
string value = (string)((PADUtil.ConcreteTableToKojunComboBox)
MStdLdtmToKojunComboBox).GetValueOfCurrentItem(kojunNameCombo.Text);
currentActivity.BWrkId = value;
}
private void SaveEventNMandID()
{
currentActivity.BWrkName = eventNameCombo.Text;
currentActivity.Name = eventNameCombo.Text;
string value = (string)((PADUtil.ConcreteTableToEventComboBox)
MEventToEventComboBox).GetValueOfCurrentItem(eventNameCombo.Text);
currentActivity.BWrkId = value;
}
I'm thinking......