Replace recursive concatenations StringBuffer by append in a single StringBuffer. Goal is performance.

demo/XidDemo.java

@@ -44,22 +44,24 @@ class XidDemo
 	    datas = new Data ();
 	    datas.setContent ("name", "Superman");
 	
-	    StringBuffer html;
+	    String htmlSource = "<div id='name'>a name</div >";
+	    StringBuffer htmlTarget;
 	    try
 	    {
-	    	html = StringPresenter.doXid ("<div id='name'>a name</div >", datas);
+	    	htmlTarget = StringPresenter.doXid (htmlSource, datas);
 	    }
 	    catch (Exception exception)
 	    {
 	    	System.out.println(exception.getMessage());
-	    	html = null;
+	    	htmlTarget = null;
 	    }
 	    System.out.println ("datas = new Data ();");
 	    System.out.println ("datas.setContent (\"name\", \"Superman\");");
 	    System.out.println ("+");
 	    System.out.println ("<div id='name'>a name</div >");
 	    System.out.println ("=>");
-	    System.out.println (html);
+	    System.out.println (htmlTarget);
+	    System.out.println ("[" + htmlSource.length() + "] => [" + htmlTarget.length() + "]");
 	}
 	
 	
@@ -73,15 +75,16 @@ class XidDemo
 	    datas.appendAttribute ("lastname", "style", "foreground: red;");
 	    datas.setAttribute ("lastname", "class", "nameClass");
 	
-	    StringBuffer html;
+	    String htmlSource = "<div id='lastname'>a last name</div >";
+	    StringBuffer htmlTarget;
 	    try
 	    {
-	    	html = StringPresenter.doXid ("<div id='lastname'>a last name</div >", datas);
+	    	htmlTarget = StringPresenter.doXid (htmlSource, datas);
 	    }
 	    catch (Exception exception)
 	    {
 	    	System.out.println(exception.getMessage());
-	    	html = null;
+	    	htmlTarget = null;
 	    }
 	    
 	    System.out.println ("datas = new Data ();");
@@ -92,7 +95,8 @@ class XidDemo
 	    System.out.println ("+");
 	    System.out.println ("<div id='lastname'>a last name</div>");
 	    System.out.println ("=>");
-	    System.out.println (html);
+	    System.out.println (htmlTarget);
+	    System.out.println ("[" + htmlSource.length() + "] => [" + htmlTarget.length() + "]");
 	}
 	
 	
@@ -108,15 +112,16 @@ class XidDemo
 	    datas.setContent ("words", 4, "echo");
 	    datas.setContent ("words", 5, "fox");
 	
-	    StringBuffer html;
+	    String htmlSource = "<ul>\n  <li id='words'>a word</li>\n</ul>";
+	    StringBuffer htmlTarget;
 	    try
 	    {
-	    	html = StringPresenter.doXid ("<ul>\n  <li id='words'>a word</li>\n</ul>", datas);
+	    	htmlTarget = StringPresenter.doXid (htmlSource, datas);
 	    }
 	    catch (Exception exception)
 	    {
 	    	System.out.println(exception.getMessage());
-	    	html = null;
+	    	htmlTarget = null;
 	    }
 	    
 	    System.out.println ("datas = new Data ();");
@@ -131,7 +136,8 @@ class XidDemo
 	    System.out.println ("  <li id='words'>a word</li>");
 	    System.out.println ("</ul>");
 	    System.out.println ("=>");
-	    System.out.println (html);
+	    System.out.println (htmlTarget);
+	    System.out.println ("[" + htmlSource.length() + "] => [" + htmlTarget.length() + "]");
 	}
 	
 	
@@ -154,15 +160,15 @@ class XidDemo
 	    source.append ("</table>");
 	    
 	    String htmlSource = source.toString ();
-	    StringBuffer html;
+	    StringBuffer htmlTarget;
 	    try
 	    {
-	    	html = StringPresenter.doXid (htmlSource, datas);
+	    	htmlTarget = StringPresenter.doXid (htmlSource, datas);
 	    }
 	    catch (Exception exception)
 	    {
 	    	System.out.println(exception.getMessage());
-	    	html = null;
+	    	htmlTarget = null;
 	    }
 	    
 	    System.out.println ("datas = new Data ();");
@@ -176,7 +182,8 @@ class XidDemo
 	    System.out.println ("+");
 	    System.out.println (htmlSource);
 	    System.out.println ("=>");
-	    System.out.println (html);
+	    System.out.println (htmlTarget);
+	    System.out.println ("[" + htmlSource.length() + "] => [" + htmlTarget.length() + "]");
 	}
 	
 	

src/fr/devinsy/xid/DomPresenter.java

@@ -116,7 +116,8 @@ public class DomPresenter extends Presenter
 		else
 		{
 			// Build the web page.
-			result = Presenter.doXid (this.doc, datas);
+			result = new StringBuffer ();
+			Presenter.doXid (result, this.doc, datas);
 		}
 
 		//
@@ -127,11 +128,12 @@ public class DomPresenter extends Presenter
 	/*
 	 * Xid a file with data.
 	 */
-	static public StringBuffer doXid (Document doc, IdsDataById datas, String webappPath) throws Exception
+	static public StringBuffer doXid (Document doc, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
-		result = Presenter.process (doc, datas, webappPath);
+		result = new StringBuffer();
+		Presenter.process (result, doc, datas);
 
 		//
 		return (result);

src/fr/devinsy/xid/FilePresenter.java

@@ -113,7 +113,8 @@ public class FilePresenter extends DomPresenter
 		}
 
 		// Build the web page.
-		result = Presenter.doXid (doc, datas);
+		result = new StringBuffer (Presenter.estimatedTargetLength(source.length()));
+		Presenter.doXid (result, doc, datas);
 
 		//
 		return (result);
@@ -123,32 +124,7 @@ public class FilePresenter extends DomPresenter
 	/*
 	 * Xid a file without data.
 	 */
-	static public StringBuffer doXid (String fileName) throws Exception
+	static public StringBuffer doXid (String filePathname) throws Exception
-	{
-		StringBuffer result;
-
-		Document doc = Presenter.fileToTree (fileName);
-
-		if (doc == null)
-		{
-			result = null;
-		}
-		else
-		{
-			Presenter.addMetaTag (doc, "generator", "XID 0.0");
-
-			result = Presenter.doXid (doc, null);
-		}
-
-		//
-		return (result);
-	}
-
-
-	/*
-	 * Xid a file without data.
-	 */
-	static public StringBuffer doXid2 (String filePathname) throws Exception
 	{
 		StringBuffer result;
 

src/fr/devinsy/xid/Presenter.java

@@ -25,14 +25,9 @@ public class Presenter
 	/*
 	 * Xid a file with data.
 	 */
-	static public StringBuffer doXid (Document doc, IdsDataById datas) throws Exception
+	static public void doXid (StringBuffer result, Document doc, IdsDataById datas) throws Exception
 	{
-		StringBuffer result;
+		Presenter.process (result, doc, datas);
-
-		result = Presenter.process (doc, datas);
-
-		//
-		return (result);
 	}
 
 	
@@ -117,27 +112,20 @@ public class Presenter
 	/*
 	 *
 	 */
-	static protected StringBuffer processChildren (Node node, IdsDataById datas) throws Exception
+	static protected void processChildren (StringBuffer result, Node node, IdsDataById datas) throws Exception
 	{
-		StringBuffer result;
+		processChildren (result, node, datas, "");
-
-		result = processChildren (node, datas, "");
-
-		//
-		return (result);
 	}
 
 
 	/*
 	 *
 	 */
-	static protected StringBuffer processChildren (Node node,
+	static protected void processChildren (StringBuffer result,
+												   Node node,
 												   IdsDataById datas,
 												   String suffix) throws Exception
 	{
-		StringBuffer result;
-		result = new StringBuffer ();
-
 		// Get the iteration strategy.
 		IdData.IterationStrategy strategy;
 
@@ -189,12 +177,12 @@ public class Presenter
 						lineCounter += 1;
 						if (lineCounter == 1)
 						{
-							result.append (process (children.item (childIndex), datas, suffix));
+							process (result, children.item (childIndex), datas, suffix);
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix));
+						process (result, children.item (childIndex), datas, suffix);
 					}	    
 				}
 				break;
@@ -209,12 +197,12 @@ public class Presenter
 	
 						if ((lineCounter == 1) || (lineCounter == 2))
 						{
-							result.append (process (children.item (childIndex), datas, suffix));
+							process (result, children.item (childIndex), datas, suffix);
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix));
+						process (result, children.item (childIndex), datas, suffix);
 					}
 				}
 				break;
@@ -229,12 +217,12 @@ public class Presenter
 						if ((attrs2 != null) &&
 								(attrs2.getNamedItem ("id") != null))
 						{
-							result.append (process (children.item (childIndex), datas, suffix));
+							process (result, children.item (childIndex), datas, suffix);
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix));
+						process (result, children.item (childIndex), datas, suffix);
 					}
 				}
 				break;
@@ -248,12 +236,12 @@ public class Presenter
 						if ((attrs2 == null) ||
 								(attrs2.getNamedItem ("id") == null))
 						{
-							result.append (process (children.item(childIndex), datas, suffix));
+							process (result, children.item(childIndex), datas, suffix);
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix));
+						process (result, children.item (childIndex), datas, suffix);
 					}
 				}
 				break;
@@ -261,13 +249,10 @@ public class Presenter
 			case ALL_ROWS:
 				for (int childIndex = 0; childIndex < childrenCount; childIndex++)
 				{
-					result.append (process (children.item(childIndex), datas, suffix));
+					process (result, children.item(childIndex), datas, suffix);
 				}
 				break;
 		}
-
-		//
-		return (result);
 	}
 
 
@@ -370,7 +355,7 @@ public class Presenter
 					if ((data == null) ||
 							(data.display () == null))
 					{
-						result.append (processChildren (node, datas, suffix));
+						processChildren (result, node, datas, suffix);
 					}
 					else
 					{
@@ -417,7 +402,7 @@ public class Presenter
 						// Insert data.
 						if ((data == null) || (data.display () == null))
 						{
-							result.append (processChildren (node, datas, suffix));
+							processChildren (result, node, datas, suffix);
 						}
 						else
 						{
@@ -455,14 +440,9 @@ public class Presenter
 	/**
 	 * 
 	 */
-	static protected StringBuffer process (Node node, IdsDataById datas) throws Exception
+	static protected void process (StringBuffer result, Node node, IdsDataById datas) throws Exception
 	{
-		StringBuffer result;
+		Presenter.process (result, node, datas, "");
-
-		result = Presenter.process (node, datas, "");
-
-		//
-		return (result);
 	}
 
 
@@ -470,16 +450,13 @@ public class Presenter
 	 * Recursive method that processes a node and any child nodes.
 	 * 
 	 */
-	static protected StringBuffer process (Node node, IdsDataById datas, String suffix) throws Exception
+	static protected void process (StringBuffer result, Node node, IdsDataById datas, String suffix) throws Exception
 	{
 		logger.debug ("process - started");
 		String TRANSITIONAL_DTD = "xhtml1-transitional.dtd";
 		String TRANSITIONAL_DOCTYPE = "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 "
 			+ "Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n";
 
-		StringBuffer result;
-		result = new StringBuffer ();
-
 		// Is there anything to do?
 		if (node != null)
 		{
@@ -514,7 +491,7 @@ public class Presenter
 							// Log.write(Log.TRACE,"systemId = " + systemId);
 						}
 	
-						result.append (Presenter.process (((Document) node).getDocumentElement(), datas, suffix));
+						Presenter.process (result, ((Document) node).getDocumentElement(), datas, suffix);
 	
 						break;
 					}
@@ -596,7 +573,6 @@ public class Presenter
 		//
 		//logger.info ("result=" + result);
 		logger.debug ("process - ended");
-		return (result);
 	}
 
 
@@ -644,7 +620,7 @@ public class Presenter
 		{
 			result.append('>');
 
-			result.append (processChildren (node, datas, suffix));
+			processChildren (result, node, datas, suffix);
 
 			result.append("</");
 			result.append(node.getNodeName());
@@ -1101,4 +1077,33 @@ public class Presenter
 		//
 		return (result);
 	}
+	
+	
+	/**
+	 * Good estimation of the target length able to optimize performance.
+	 */
+	static int estimatedTargetLength(long sourceLength)
+	{
+		int result;
+	
+		if (sourceLength < 1000)
+		{
+			result = (int) (sourceLength*5);
+		}
+		else if (sourceLength < 50000)
+		{
+			result = (int) (sourceLength*2);
+		}
+		else if (sourceLength < 800000)
+		{
+			result = (int) (100000);
+		}
+		else
+		{
+			result = (int) (sourceLength + 30000);
+		}
+		
+		//
+		return(result);
+	}
 }

src/fr/devinsy/xid/StringPresenter.java

@@ -98,8 +98,8 @@ public class StringPresenter extends DomPresenter
 			doc = buildTree (new ByteArrayInputStream (htmlSource.getBytes ()));
 		}
 
-		StringBuffer htmlTarget;
+		StringBuffer htmlTarget = new StringBuffer (Presenter.estimatedTargetLength(this.html.length()));
-		htmlTarget = Presenter.doXid (doc, datas);
+		Presenter.doXid (htmlTarget, doc, datas);
 
 		if (htmlTarget == null)
 		{