svn commit: r518479 - /db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java

[ma...@apache.org]

Author: mamta
Date: Wed Mar 14 21:53:37 2007
New Revision: 518479

URL: http://svn.apache.org/viewvc?view=rev&rev=518479
Log:
Some cosmetic changes to CollatorSQLChar. Changed the class comment to get rid of the copy and paste from the superclass's class comment.
Changed the comments for class fields to javadocs. Changed one of the class field's name so it indicates it's purpose rather than it's
field's type. And lastly, added additional comments to the like() method.


Modified:
    db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java

Modified: db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java?view=diff&rev=518479&r1=518478&r2=518479
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/iapi/types/CollatorSQLChar.java Wed Mar 14 21:53:37 2007
@@ -33,21 +33,11 @@
 import java.text.RuleBasedCollator;
 
 /**
- * CollatorSQLChar satisfies the DataValueDescriptor
- * interfaces (i.e., OrderableDataType). It implements an String holder,
- * e.g. for storing a column value; it can be specified
- * when constructed to not allow nulls. Nullability cannot be changed
- * after construction.
- * <p>
- * Because OrderableDataType is a subclass of DataType,
- * CollatorSQLChar can play a role in either a DataType/ValueRow
- * or a OrderableDataType/KeyRow, interchangeably.
- * 
- * This class differs from SQLChar based on how the 2 classes use different
- * collations to collate their data. SQLChar uses Derby's default collation
- * which is UCS_BASIC. Whereas, this class uses the RuleBasedCollator object 
- * that was passed to it in it's constructor and that RuleBasedCollator object  
- * decides the collation.
+ * CollatorSQLChar class differs from SQLChar based on how the 2 classes use 
+ * different collations to collate their data. SQLChar uses Derby's default 
+ * collation which is UCS_BASIC. Whereas, this class uses the RuleBasedCollator  
+ * object that was passed to it in it's constructor and that RuleBasedCollator   
+ * object decides the collation.
  * 
  * In Derby 10.3, this class will be passed a RuleBasedCollator which is based 
  * on the database's territory. In future releases of Derby, this class can be 
@@ -55,15 +45,19 @@
  * just passing an appropriate RuleBasedCollator object for that kind of 
  * collation.
  */
-public class CollatorSQLChar
-	extends SQLChar
+public class CollatorSQLChar extends SQLChar
 {
-	//Use this object for collation
-	RuleBasedCollator rbc;
-	//Following is the array holding a series of collation elements for the 
-	//string. It will be used in the like method 
+	/** Use this object for collation on character datatypes */
+	RuleBasedCollator collatorForCharacterDatatypes;
+	/**
+	 * Following is the array holding a series of collation elements for the
+	 * string. It will be used in the like method 
+	 */
 	private int[]	collationElementsForString;
-	//number of valid collation elements in the array above. 
+	/** 
+	 * Number of valid collation elements in the array above. Note that this 
+	 * might be smaller than the actual size of the array above
+	 */
 	private int		countOfCollationElements;
 
 	/*
@@ -77,19 +71,19 @@
 	{
 	}
 
-	public CollatorSQLChar(String val, RuleBasedCollator rbc)
+	public CollatorSQLChar(String val, RuleBasedCollator collatorForCharacterDatatypes)
 	{
 		super(val);
-		this.rbc = rbc;
+		this.collatorForCharacterDatatypes = collatorForCharacterDatatypes;
 	}
 
 	/**
 	 * Set the RuleBasedCollator for this instance of CollatorSQLChar. It will
 	 * be used to do the collation.
 	 */
-	private void setCollator(RuleBasedCollator rbc)
+	private void setCollator(RuleBasedCollator collatorForCharacterDatatypes)
 	{
-		this.rbc = rbc;
+		this.collatorForCharacterDatatypes = collatorForCharacterDatatypes;
 	}
 
 	/**
@@ -124,7 +118,7 @@
 
 		collationElementsForString = new int[getLength()];
 
-		CollationElementIterator cei = rbc.getCollationElementIterator(getString());
+		CollationElementIterator cei = collatorForCharacterDatatypes.getCollationElementIterator(getString());
 		int nextInt;
 		while ((nextInt = cei.next()) != CollationElementIterator.NULLORDER)
 		{
@@ -162,6 +156,9 @@
 
 	/**
 	 * This method implements the like function for char (with no escape value).
+	 * The difference in this method and the same method in superclass is that
+	 * here we use special Collator object to do the comparison rather than
+	 * using the Collator object associated with the default jvm locale.
 	 *
 	 * @param pattern		The pattern to use
 	 *
@@ -180,7 +177,7 @@
 				getCountOfCollationElements(),
 				patternSQLChar.getCollationElementsForString(),
 				patternSQLChar.getCountOfCollationElements(),
-				rbc);
+				collatorForCharacterDatatypes);
 
 		return SQLBoolean.truthValue(this,
 									 pattern,
@@ -198,7 +195,7 @@
 	{
 		try
 		{
-			return new CollatorSQLChar(getString(), rbc);
+			return new CollatorSQLChar(getString(), collatorForCharacterDatatypes);
 		}
 		catch (StandardException se)
 		{
@@ -214,7 +211,7 @@
 	public DataValueDescriptor getNewNull()
 	{
 		CollatorSQLChar result = new CollatorSQLChar();
-		result.setCollator(rbc);
+		result.setCollator(collatorForCharacterDatatypes);
 		return result;
 	}