Refactored StringBuilder to use a List<String> as a buffer and use

String.join() to build the result string more efficiently than string concatenation. Introduced new method setDelimiter on CommaDelimitedListBuilder to support a custom delimiter when building a string. The delimiter defaults to a comma but can be changed as required.
apex-enterprise-patterns · Apr 6, 2014 · ed6df6f · ed6df6f
1 parent 27687aa
commit ed6df6f
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Showing 2 changed files with 71 additions and 33 deletions.
diff --git a/fflib/src/classes/fflib_StringBuilder.cls b/fflib/src/classes/fflib_StringBuilder.cls
@@ -31,7 +31,7 @@
  **/
 public virtual with sharing class fflib_StringBuilder
 {
-	protected String m_stringValue;
+	protected List<String> buffer = new List<String>();
 
 	/**
 	 * Construct an empty StringBuilder
@@ -51,52 +51,64 @@ public virtual with sharing class fflib_StringBuilder
 	 **/
 	public virtual void add(List<String> values)
 	{
-		for(String value : values)
-			add(value);
+		buffer.addAll(values);
 	}
 
 	/**
 	 * Add the given value to the StringBuilder
 	 **/
 	public virtual void add(String value)
 	{
-		m_stringValue = ( m_stringValue==null ? value : m_stringValue + value );
+		buffer.add(value);
+	}
+
+	public virtual override String toString()
+	{
+		return String.join(buffer, '');
 	}
 
 	/**
 	 * Return the state of the StringBuilder
 	 **/
 	public virtual String getStringValue()
 	{
-		return m_stringValue;
+		return toString();
 	}
 
-
 	/**
 	 * Subclasses the StringBuilder to produce a comma delimited contactination of strings
 	 **/
 	public virtual with sharing class CommaDelimitedListBuilder extends fflib_StringBuilder
 	{
+		String itemPrefix = '';
+		String delimiter = ',';
+
 		public CommaDelimitedListBuilder() {}
 
 		public CommaDelimitedListBuilder(List<String> values)
 		{
 			super(values);
 		}
 
-		public virtual override void add(String value)
+		public void setItemPrefix(String itemPrefix)
 		{
-			m_stringValue = ( m_stringValue==null ? '{0}' + value : m_stringValue + ',{0}' + value );
+			this.itemPrefix = itemPrefix;
 		}
 
-		public override String getStringValue()
+		public void setDelimiter(String delimiter)
 		{
-			return getStringValue('');
+			this.delimiter = delimiter;
 		}
 
 		public String getStringValue(String itemPrefix)
 		{
-			return m_stringValue==null ? null : String.format(m_stringValue,new List<String>{itemPrefix});
+			setItemPrefix(itemPrefix);
+			return toString();
+		}
+
+		public override String toString()
+		{
+			return itemPrefix + String.join(buffer, delimiter + itemPrefix);
 		}
 	}
 
@@ -113,14 +125,13 @@ public virtual with sharing class fflib_StringBuilder
 		public FieldListBuilder(List<Schema.SObjectField> values, List<Schema.Fieldset> fieldSets)
 		{
 			// Create a distinct set of fields (or field paths) to select
-			Set<String> selectFields = new Set<String>();			
 			for(Schema.SObjectField value : values)
-				selectFields.add(value.getDescribe().getName());
+				add(String.valueOf(value)); // Alternative to value.getDescribe().getName()
+
 			if(fieldSets!=null)
 				for(Schema.Fieldset fieldSet : fieldSets)
 					for(Schema.FieldSetMember fieldSetMember : fieldSet.getFields())
-						selectFields.add(fieldSetMember.getFieldPath());
-			add(new List<String>(selectFields));
+						add(fieldSetMember.getFieldPath());
 		}
 	}
 

diff --git a/fflib/src/classes/fflib_StringBuilderTest.cls b/fflib/src/classes/fflib_StringBuilderTest.cls
@@ -27,40 +27,67 @@
 @IsTest
 private with sharing class fflib_StringBuilderTest 
 {	
-    static testMethod void testfflib_StringBuilder1()
-    {
+	static testMethod void testfflib_StringBuilder1()
+	{
 		fflib_StringBuilder sb = new fflib_StringBuilder();
 		sb.add('this is a string');
 		sb.add(new List<String>{', which is made',' up from\r ','a number of smaller strings', '. 5 in this case!'});
 		system.assertEquals(sb.getStringValue(),'this is a string, which is made up from\r a number of smaller strings. 5 in this case!');	
-    }
+	}
 
-    static testMethod void testfflib_StringBuilder2()
-    {
+	static testMethod void testfflib_StringBuilder2()
+	{
 		fflib_StringBuilder sb = new fflib_StringBuilder(new List<String>{'apples',' and ','pears',': stairs. '});
 		sb.add('this is a string');
 		sb.add(new List<String>{', which is made',' up from\r ','a number of smaller strings', '. 5 in this case!'});
 		system.assertEquals(sb.getStringValue(),'apples and pears: stairs. this is a string, which is made up from\r a number of smaller strings. 5 in this case!');	
-    }
+	}
 
-    static testMethod void testCommaDelimitedBuilder1()
-    {
+	static testMethod void testCommaDelimitedBuilder1()
+	{
 		fflib_StringBuilder.CommaDelimitedListBuilder sb = new fflib_StringBuilder.CommaDelimitedListBuilder();
 		sb.add('a');
 		sb.add(new List<String>{'b','c','d'});
 		system.assertEquals(sb.getStringValue(),'a,b,c,d');	
-    }
+	}
 
-    static testMethod void testCommaDelimitedBuilder2()
-    {
+	static testMethod void testCommaDelimitedBuilder2()
+	{
 		fflib_StringBuilder.CommaDelimitedListBuilder sb = new fflib_StringBuilder.CommaDelimitedListBuilder(new List<String>{'x','y'});
 		sb.add('a');
 		sb.add(new List<String>{'b','c','d'});
 		system.assertEquals(sb.getStringValue(),'x,y,a,b,c,d');	
-    }
+	}
+
+	static testMethod void testCommanDelimitedBuilderWithItemPrefix()
+	{
+		fflib_StringBuilder.CommaDelimitedListBuilder sb = new fflib_StringBuilder.CommaDelimitedListBuilder(new List<String>{'x','y'});
+		sb.add('a');
+		sb.add(new List<String>{'b','c','d'});
+		system.assertEquals(sb.getStringValue('$'),'$x,$y,$a,$b,$c,$d');	
+	}
+
+	static testMethod void testCommanDelimitedBuilderWithAlternativeDelimiter()
+	{
+		fflib_StringBuilder.CommaDelimitedListBuilder sb = new fflib_StringBuilder.CommaDelimitedListBuilder(new List<String>{'x','y'});
+		sb.setDelimiter(';');
+		sb.add('a');
+		sb.add(new List<String>{'b','c','d'});
+		system.assertEquals(sb.getStringValue(),'x;y;a;b;c;d');	
+	}
+
+	static testMethod void testCommanDelimitedBuilderWithAlternativeDelimiterAndPrefix()
+	{
+		fflib_StringBuilder.CommaDelimitedListBuilder sb = new fflib_StringBuilder.CommaDelimitedListBuilder(new List<String>{'x','y'});
+		sb.setItemPrefix('#');
+		sb.setDelimiter(':');
+		sb.add('a');
+		sb.add(new List<String>{'b','c','d'});
+		system.assertEquals(sb.getStringValue(),'#x:#y:#a:#b:#c:#d');
+	}
 
-    static testMethod void testFieldListBuilder()
-    {
+	static testMethod void testFieldListBuilder()
+	{
 		List<Schema.SObjectField> fields = new List<Schema.SObjectField> { Account.Name, Account.Id, Account.AccountNumber, Account.AccountNumber, Account.AnnualRevenue };
 		fflib_StringBuilder.FieldListBuilder sb = new fflib_StringBuilder.FieldListBuilder(fields);
 		List<String> fieldList = sb.getStringValue().split(',');
@@ -70,10 +97,10 @@ private with sharing class fflib_StringBuilderTest
 		system.assert(fieldSet.contains('Id'));
 		system.assert(fieldSet.contains('AccountNumber'));
 		system.assert(fieldSet.contains('AnnualRevenue'));
-    }
+	}
 
-    static testMethod void testMultiCurrencyFieldListBuilder()
-    {
+	static testMethod void testMultiCurrencyFieldListBuilder()
+	{
 		List<Schema.SObjectField> fields = new List<Schema.SObjectField> { Account.Name, Account.Id, Account.AccountNumber, Account.AnnualRevenue };
 		fflib_StringBuilder.MultiCurrencyFieldListBuilder sb = new fflib_StringBuilder.MultiCurrencyFieldListBuilder(fields);
 		List<String> fieldList = sb.getStringValue().split(',');
@@ -84,5 +111,5 @@ private with sharing class fflib_StringBuilderTest
 		system.assert(fieldSet.contains('AnnualRevenue'));
 		if(UserInfo.isMultiCurrencyOrganization())
 			system.assert(fieldSet.contains('CurrencyIsoCode'));
-    }
+	}
 }