add ColumnBuilder utility for simplifying table construction

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@276 f203690c-595d-4dc9-a70b-905162fa7fd2

2 files changed, 141 insertions, 5 deletions

diff --git a/src/java/com/healthmarketscience/jackcess/ColumnBuilder.java b/src/java/com/healthmarketscience/jackcess/ColumnBuilder.java
new file mode 100644
index 0000000..860e438
--- /dev/null
+++ b/src/java/com/healthmarketscience/jackcess/ColumnBuilder.java
@@ -0,0 +1,138 @@
+// Copyright (c) 2008 Health Market Science, Inc.
+
+package com.healthmarketscience.jackcess;
+
+import java.sql.SQLException;
+
+/**
+ * Builder style class for constructing a Column.
+ *
+ * @author James Ahlborn
+ */
+public class ColumnBuilder {
+
+  /** name of the new column */
+  private String _name;
+  /** the type of the new column */
+  private DataType _type;
+  /** optional length for the new column */
+  private Integer _length;
+  /** optional precision for the new column */
+  private Integer _precision;
+  /** optional scale for the new column */
+  private Integer _scale;
+  /** whether or not the column is auto-number */
+  private boolean _autoNumber;
+
+  public ColumnBuilder(String name) {
+    this(name, null);
+  }
+  
+  public ColumnBuilder(String name, DataType type) {
+    _name = name;
+    _type = type;
+  }
+
+  /**
+   * Sets the type for the new column.
+   */
+  public ColumnBuilder setType(DataType type) {
+    _type = type;
+    return this;
+  }
+
+  /**
+   * Sets the type for the new column based on the given SQL type.
+   */
+  public ColumnBuilder setSQLType(int type) throws SQLException {
+    return setSQLType(type, 0);
+  }
+  
+  /**
+   * Sets the type for the new column based on the given SQL type and target
+   * data length (in type specific units).
+   */
+  public ColumnBuilder setSQLType(int type, int lengthInUnits)
+    throws SQLException
+  {
+    return setType(DataType.fromSQLType(type, lengthInUnits));
+  }
+
+  /**
+   * Sets the precision for the new column.
+   */
+  public ColumnBuilder setPrecision(int newPrecision) {
+    _precision = newPrecision;
+    return this;
+  }
+
+  /**
+   * Sets the scale for the new column.
+   */
+  public ColumnBuilder setScale(int newScale) {
+    _scale = newScale;
+    return this;
+  }
+
+  /**
+   * Sets the length (in bytes) for the new column.
+   */
+  public ColumnBuilder setLength(int length) {
+    _length = length;
+    return this;
+  }
+
+  /**
+   * Sets the length (in type specific units) for the new column.
+   */
+  public ColumnBuilder setLengthInUnits(int unitLength) {
+    return setLength(_type.getUnitSize() * unitLength);
+  }
+  
+  /**
+   * Sets whether of not the new column is an auto-number column.
+   */
+  public ColumnBuilder setAutoNumber(boolean autoNumber) {
+    _autoNumber = autoNumber;
+    return this;
+  }
+
+  /**
+   * Sets all attributes except name from the given Column template.
+   */
+  public ColumnBuilder setFromColumn(Column template) {
+    DataType type = template.getType();
+    setType(type);
+    setLength(template.getLength());
+    setAutoNumber(template.isAutoNumber());
+    if(type.getHasScalePrecision()) {
+      setScale(template.getScale());
+      setPrecision(template.getPrecision());
+    }
+    
+    return this;
+  }
+
+  /**
+   * Creates a new Column with the currently configured attributes.
+   */
+  public Column toColumn() {
+    Column col = new Column();
+    col.setName(_name);
+    col.setType(_type);
+    if(_length != null) {
+      col.setLength(_length.shortValue());
+    }
+    if(_precision != null) {
+      col.setPrecision(_precision.byteValue());
+    }
+    if(_scale != null) {
+      col.setScale(_scale.byteValue());
+    }
+    if(_autoNumber) {
+      col.setAutoNumber(true);
+    }
+    return col;
+  }
+  
+}
diff --git a/src/java/com/healthmarketscience/jackcess/Database.java b/src/java/com/healthmarketscience/jackcess/Database.java
index c6b5a0e..123445f 100644
--- a/src/java/com/healthmarketscience/jackcess/Database.java
+++ b/src/java/com/healthmarketscience/jackcess/Database.java
@@ -833,11 +833,9 @@ public class Database
     String[] columnNames = line.split(delim);
       
     for (int i = 0; i < columnNames.length; i++) {
-      Column column = new Column();
-      column.setName(escape(columnNames[i]));
-      column.setType(DataType.TEXT);
-      column.setLength((short)DataType.TEXT.getMaxSize());
-      columns.add(column);
+      columns.add(new ColumnBuilder(escape(columnNames[i]), DataType.TEXT)
+                  .setLength((short)DataType.TEXT.getMaxSize())
+                  .toColumn());
     }
 
     try {