diff --git a/build/classes/fr/devinsy/xid/DomPresenter.class b/build/classes/fr/devinsy/xid/DomPresenter.class
index 0771c5a..0a5a7e0 100644
Binary files a/build/classes/fr/devinsy/xid/DomPresenter.class and b/build/classes/fr/devinsy/xid/DomPresenter.class differ
diff --git a/build/classes/fr/devinsy/xid/FilePresenter.class b/build/classes/fr/devinsy/xid/FilePresenter.class
index 3d7ea46..ef17491 100644
Binary files a/build/classes/fr/devinsy/xid/FilePresenter.class and b/build/classes/fr/devinsy/xid/FilePresenter.class differ
diff --git a/build/classes/fr/devinsy/xid/Presenter.class b/build/classes/fr/devinsy/xid/Presenter.class
index 57a5d04..0a5522a 100644
Binary files a/build/classes/fr/devinsy/xid/Presenter.class and b/build/classes/fr/devinsy/xid/Presenter.class differ
diff --git a/build/classes/fr/devinsy/xid/StringPresenter.class b/build/classes/fr/devinsy/xid/StringPresenter.class
index 1c1107a..1a672c7 100644
Binary files a/build/classes/fr/devinsy/xid/StringPresenter.class and b/build/classes/fr/devinsy/xid/StringPresenter.class differ
diff --git a/demo/XidDemo.java b/demo/XidDemo.java
index 8a35774..24ddb6e 100644
--- a/demo/XidDemo.java
+++ b/demo/XidDemo.java
@@ -25,187 +25,277 @@ class XidDemo
    */
   public static void main (String[] args)
   {
-    System.out.println("Hello World!");
+	System.out.println("Hello World!");
+	
+	//test ();
+	
+	//
+	Data datas;
+	IdData tag;
+	
+	
+	
+	
+	// Step #01.
+	{
+	    System.out.println ("----------------------------");
+	    
+	    // Populate attributes.
+	    datas = new Data ();
+	    datas.setContent ("name", "Superman");
+	
+	    StringBuffer html;
+	    try
+	    {
+	    	html = StringPresenter.doXid ("<div id='name'>a name</div >", datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = 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);
+	}
+	
+	
+	// Step #02.
+	{
+	    System.out.println ("----------------------------");
+	    // Populate attributes.
+	    datas = new Data ();
+	    datas.setContent ("lastname", "Spiderman");
+	    datas.appendAttribute ("lastname", "style", "background: blue;");
+	    datas.appendAttribute ("lastname", "style", "foreground: red;");
+	    datas.setAttribute ("lastname", "class", "nameClass");
+	
+	    StringBuffer html;
+	    try
+	    {
+	    	html = StringPresenter.doXid ("<div id='lastname'>a last name</div >", datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    
+	    System.out.println ("datas = new Data ();");
+	    System.out.println ("datas.setContent (\"lastname\", \"Spiderman\");");
+	    System.out.println ("datas.appendAttribute (\"lastname\", \"style\", \"background: blue;\");");
+	    System.out.println ("datas.appendAttribute (\"lastname\", \"style\", \"foreground: red;\");");
+	    System.out.println ("datas.setAttribute (\"lastname\", \"class\", \"nameClass\");");
+	    System.out.println ("+");
+	    System.out.println ("<div id='lastname'>a last name</div>");
+	    System.out.println ("=>");
+	    System.out.println (html);
+	}
+	
+	
+	// Step #03.
+	{
+	    System.out.println ("----------------------------");
+	    // Populate attributes.
+	    datas = new Data ();
+	    datas.setContent ("words", 0, "alpha");
+	    datas.setContent ("words", 1, "bravo");
+	    datas.setContent ("words", 2, "charlie");
+	    datas.setContent ("words", 3, "delta");
+	    datas.setContent ("words", 4, "echo");
+	    datas.setContent ("words", 5, "fox");
+	
+	    StringBuffer html;
+	    try
+	    {
+	    	html = StringPresenter.doXid ("<ul>\n  <li id='words'>a word</li>\n</ul>", datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    
+	    System.out.println ("datas = new Data ();");
+	    System.out.println ("datas.setContent (\"words\", 0, \"alpha\");");
+	    System.out.println ("datas.setContent (\"words\", 1, \"bravo\");");
+	    System.out.println ("datas.setContent (\"words\", 2, \"charlie\");");
+	    System.out.println ("datas.setContent (\"words\", 3, \"delta\");");
+	    System.out.println ("datas.setContent (\"words\", 4, \"echo\");");
+	    System.out.println ("datas.setContent (\"words\", 5, \"fox\");");
+	    System.out.println ("+");
+	    System.out.println ("<ul>");
+	    System.out.println ("  <li id='words'>a word</li>");
+	    System.out.println ("</ul>");
+	    System.out.println ("=>");
+	    System.out.println (html);
+	}
+	
+	
+	// Step #04.
+	{
+	    System.out.println ("----------------------------");
+	    // Populate attributes.
+	    datas = new Data ();
+	    datas.setContent ("identity", 0, "last_name", "Jemba");
+	    datas.setContent ("identity", 0, "first_name", "Epo");
+	    datas.setContent ("identity", 1, "last_name", "Momon");
+	    datas.setContent ("identity", 1, "first_name", "Christian");
+	    datas.setContent ("identity", 2, "last_name", "Tronche");
+	    datas.setContent ("identity", 2, "first_name", "Christophe");
+	
+	
+	    StringBuffer source = new StringBuffer ();
+	    source.append ("<table>\n");
+	    source.append ("  <tr id='identity'><td>noid</td><td id='first_name'>Jean</td><td id='last_name'>Reve</td></tr>\n");
+	    source.append ("</table>");
+	    
+	    String htmlSource = source.toString ();
+	    StringBuffer html;
+	    try
+	    {
+	    	html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    
+	    System.out.println ("datas = new Data ();");
+	    System.out.println ("datas.setContent (\"identity\", 0, \"last_name\", \"Jemba\");");
+	    System.out.println ("datas.setContent (\"identity\", 0, \"first_name\", \"Epo\");");
+	    System.out.println ("datas.setContent (\"identity\", 1, \"last_name\", \"Momon\");");
+	    System.out.println ("datas.setContent (\"identity\", 1, \"first_name\", \"Christian\");");
+	    System.out.println ("datas.setContent (\"identity\", 2, \"last_name\", \"Tronche\");");
+	    System.out.println ("datas.setContent (\"identity\", 2, \"first_name\", \"Christophe\");");
+	
+	    System.out.println ("+");
+	    System.out.println (htmlSource);
+	    System.out.println ("=>");
+	    System.out.println (html);
+	}
+	
+	
+	// Step #05.
+	{
+	    System.out.println ("----------------------------");
+	    // Populate attributes.
+	    datas = new Data ();
+	    datas.setContent ("identity", 0, "last_name", "Jemba");
+	    datas.setContent ("identity", 0, "first_name", "Epo");
+	    datas.setContent ("identity", 1, "last_name", "Momon");
+	    datas.setContent ("identity", 1, "first_name", "Christian");
+	    datas.setContent ("identity", 2, "last_name", "Tronche");
+	    datas.setContent ("identity", 2, "first_name", "Christophe");
+	    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ONLY_ROWS_WITH_ID);
+	    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ONLY_ROWS_WITHOUT_ID);
+	    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ALL_ROWS);
+	
+	    //
+	    StringBuffer source = new StringBuffer ();
+	    source.append ("<table id=\"identities\">\n");
+	    source.append ("  <tr id='the_head'><th>noid</th><th>First Name</th><th>Last Name</th></tr>\n");
+	    source.append ("  <tr id='identity'><td>noid</td><td id='first_name'>Jean</td><td id='last_name'>Reve</td></tr>\n");
+	    source.append ("  <tr id='identity_bis'><td>noid</td><td id='first_name_bis'>a first name</td><td id='last_name_bis'>a last name</td></tr>\n");
+	    source.append ("  <tr><td>noid</td><td id='first_name_ter'>a first name more</td><td id='last_name_ter'>a last name more</td></tr>\n");
+	    source.append ("</table>\n");
+	    String htmlSource = source.toString ();
+	    
+	    System.out.println ("datas = new Data ();");
+	    System.out.println ("datas.setContent (\"identity\", 0, \"first_name\", \"Epo\");");
+	    System.out.println ("datas.setContent (\"identity\", 0, \"last_name\", \"Jemba\");");
+	    System.out.println ("datas.setContent (\"identity\", 1, \"first_name\", \"Christian\");");
+	    System.out.println ("datas.setContent (\"identity\", 1, \"last_name\", \"Momon\");");
+	    System.out.println ("datas.setContent (\"identity\", 2, \"first_name\", \"Christophe\");");
+	    System.out.println ("datas.setContent (\"identity\", 2, \"last_name\", \"Tronche\");");
+	
+	    System.out.println ("+");
+	    System.out.println (htmlSource);
+	    System.out.println ("=>");
+	
+	    
+	    // #05.1
+	    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_FIRST_ROW);
+	    System.out.println ("ONLY_FIRST_ROW:");
+	    StringBuffer html;
+	    try
+	    {
+	    	html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println(exception.getMessage());
+	    	html = null;
+	    }
+	    System.out.println (html);
+	    System.out.println ("");
+	    
+	    
+	    // #05.2
+	    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_FIRST_TWO_ROWS);
+	    System.out.println ("ONLY_FIRST_TWO_ROWS:");
+	    try
+	    {
+	    	html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    System.out.println (html);
+	    System.out.println ("");
 
-    //test ();
+	    
+	    // #05.3
+	    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_ROWS_WITH_ID);
+	    System.out.println ("ONLY_ROWS_WITH_ID:");
+	    try
+	    {
+	    	html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    System.out.println (html);
+	    System.out.println ("");
 
-    //
-    Data datas;
-    IdData tag;
-
-
-
-    String htmlSource;
-    StringBuffer html;
-    StringBuffer errorMessage;
-
-    // Populate attributes of Test 03.
-    System.out.println ("----------------------------");
-    datas = new Data ();
-    datas.setContent ("name", "Superman");
-
-    errorMessage = new StringBuffer ();
-    html = StringPresenter.doXid ("<div id='name'>a name</div >", datas, errorMessage);
-    
-    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);
-
-
-    // Populate attributes of Test 03.
-    System.out.println ("----------------------------");
-    datas = new Data ();
-    datas.setContent ("lastname", "Spiderman");
-    datas.appendAttribute ("lastname", "style", "background: blue;");
-    datas.appendAttribute ("lastname", "style", "foreground: red;");
-    datas.setAttribute ("lastname", "class", "nameClass");
-
-
-    errorMessage = new StringBuffer ();
-    html = StringPresenter.doXid ("<div id='lastname'>a last name</div >", datas, errorMessage);
-    
-    System.out.println ("datas = new Data ();");
-    System.out.println ("datas.setContent (\"lastname\", \"Spiderman\");");
-    System.out.println ("datas.appendAttribute (\"lastname\", \"style\", \"background: blue;\");");
-    System.out.println ("datas.appendAttribute (\"lastname\", \"style\", \"foreground: red;\");");
-    System.out.println ("datas.setAttribute (\"lastname\", \"class\", \"nameClass\");");
-    System.out.println ("+");
-    System.out.println ("<div id='lastname'>a last name</div>");
-    System.out.println ("=>");
-    System.out.println (html);
-
-
-    // Populate attributes of Test 03.
-    System.out.println ("----------------------------");
-    datas = new Data ();
-    datas.setContent ("words", 0, "alpha");
-    datas.setContent ("words", 1, "bravo");
-    datas.setContent ("words", 2, "charlie");
-    datas.setContent ("words", 3, "delta");
-    datas.setContent ("words", 4, "echo");
-    datas.setContent ("words", 5, "fox");
-
-
-    errorMessage = new StringBuffer ();
-    html = StringPresenter.doXid ("<ul>\n  <li id='words'>a word</li>\n</ul>", datas, errorMessage);
-    
-    System.out.println ("datas = new Data ();");
-    System.out.println ("datas.setContent (\"words\", 0, \"alpha\");");
-    System.out.println ("datas.setContent (\"words\", 1, \"bravo\");");
-    System.out.println ("datas.setContent (\"words\", 2, \"charlie\");");
-    System.out.println ("datas.setContent (\"words\", 3, \"delta\");");
-    System.out.println ("datas.setContent (\"words\", 4, \"echo\");");
-    System.out.println ("datas.setContent (\"words\", 5, \"fox\");");
-    System.out.println ("+");
-    System.out.println ("<ul>");
-    System.out.println ("  <li id='words'>a word</li>");
-    System.out.println ("</ul>");
-    System.out.println ("=>");
-    System.out.println (html);
-
-
-    // Populate attributes of Test 03.
-    System.out.println ("----------------------------");
-    datas = new Data ();
-    datas.setContent ("identity", 0, "last_name", "Jemba");
-    datas.setContent ("identity", 0, "first_name", "Epo");
-    datas.setContent ("identity", 1, "last_name", "Momon");
-    datas.setContent ("identity", 1, "first_name", "Christian");
-    datas.setContent ("identity", 2, "last_name", "Tronche");
-    datas.setContent ("identity", 2, "first_name", "Christophe");
-
-
-    errorMessage = new StringBuffer ();
-    StringBuffer source = new StringBuffer ();
-    source.append ("<table>\n");
-    source.append ("  <tr id='identity'><td>noid</td><td id='first_name'>Jean</td><td id='last_name'>Reve</td></tr>\n");
-    source.append ("</table>");
-    htmlSource = source.toString ();
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    
-    System.out.println ("datas = new Data ();");
-    System.out.println ("datas.setContent (\"identity\", 0, \"last_name\", \"Jemba\");");
-    System.out.println ("datas.setContent (\"identity\", 0, \"first_name\", \"Epo\");");
-    System.out.println ("datas.setContent (\"identity\", 1, \"last_name\", \"Momon\");");
-    System.out.println ("datas.setContent (\"identity\", 1, \"first_name\", \"Christian\");");
-    System.out.println ("datas.setContent (\"identity\", 2, \"last_name\", \"Tronche\");");
-    System.out.println ("datas.setContent (\"identity\", 2, \"first_name\", \"Christophe\");");
-
-    System.out.println ("+");
-    System.out.println (htmlSource);
-    System.out.println ("=>");
-    System.out.println (html);
-
-
-    // Populate attributes of Test 03.
-    System.out.println ("----------------------------");
-    datas = new Data ();
-    datas.setContent ("identity", 0, "last_name", "Jemba");
-    datas.setContent ("identity", 0, "first_name", "Epo");
-    datas.setContent ("identity", 1, "last_name", "Momon");
-    datas.setContent ("identity", 1, "first_name", "Christian");
-    datas.setContent ("identity", 2, "last_name", "Tronche");
-    datas.setContent ("identity", 2, "first_name", "Christophe");
-    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ONLY_ROWS_WITH_ID);
-    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ONLY_ROWS_WITHOUT_ID);
-    //datas.setIterationStrategy ("identity", IdsDataByIndex.IterationStrategy.ALL_ROWS);
-
-
-    errorMessage = new StringBuffer ();
-    source = new StringBuffer ();
-    source.append ("<table id=\"identities\">\n");
-    source.append ("  <tr id='the_head'><th>noid</th><th>First Name</th><th>Last Name</th></tr>\n");
-    source.append ("  <tr id='identity'><td>noid</td><td id='first_name'>Jean</td><td id='last_name'>Reve</td></tr>\n");
-    source.append ("  <tr id='identity_bis'><td>noid</td><td id='first_name_bis'>a first name</td><td id='last_name_bis'>a last name</td></tr>\n");
-    source.append ("  <tr><td>noid</td><td id='first_name_ter'>a first name more</td><td id='last_name_ter'>a last name more</td></tr>\n");
-    source.append ("</table>\n");
-    htmlSource = source.toString ();
-    
-    System.out.println ("datas = new Data ();");
-    System.out.println ("datas.setContent (\"identity\", 0, \"first_name\", \"Epo\");");
-    System.out.println ("datas.setContent (\"identity\", 0, \"last_name\", \"Jemba\");");
-    System.out.println ("datas.setContent (\"identity\", 1, \"first_name\", \"Christian\");");
-    System.out.println ("datas.setContent (\"identity\", 1, \"last_name\", \"Momon\");");
-    System.out.println ("datas.setContent (\"identity\", 2, \"first_name\", \"Christophe\");");
-    System.out.println ("datas.setContent (\"identity\", 2, \"last_name\", \"Tronche\");");
-
-    System.out.println ("+");
-    System.out.println (htmlSource);
-    System.out.println ("=>");
-
-    
-    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_FIRST_ROW);
-    System.out.println ("ONLY_FIRST_ROW:");
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    System.out.println (html);
-
-    System.out.println ("");
-    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_FIRST_TWO_ROWS);
-    System.out.println ("ONLY_FIRST_TWO_ROWS:");
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    System.out.println (html);
-
-    System.out.println ("");
-    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_ROWS_WITH_ID);
-    System.out.println ("ONLY_ROWS_WITH_ID:");
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    System.out.println (html);
-
-    System.out.println ("");
-    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_ROWS_WITHOUT_ID);
-    System.out.println ("ONLY_ROWS_WITHOUT_ID:");
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    System.out.println (html);
-
-    System.out.println ("");
-    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ALL_ROWS);
-    System.out.println ("ALL_ROWS:");
-    html = StringPresenter.doXid (htmlSource, datas, errorMessage);
-    System.out.println (html);
-
-
-  }
+	    
+	    // #05.4
+	    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ONLY_ROWS_WITHOUT_ID);
+	    System.out.println ("ONLY_ROWS_WITHOUT_ID:");
+	    try
+	    {
+	    	html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+	    System.out.println (html);
+	    System.out.println ("");
+	    
+	    
+	    // #05.5
+	    datas.setIterationStrategy ("identities", IdData.IterationStrategy.ALL_ROWS);
+	    System.out.println ("ALL_ROWS:");
+	    try
+	    {
+		    html = StringPresenter.doXid (htmlSource, datas);
+	    }
+	    catch (Exception exception)
+	    {
+	    	System.out.println("Error " + exception.getMessage());
+	    	html = null;
+	    }
+		    System.out.println (html);
+	    }
+  	}
 }
diff --git a/src/fr/devinsy/xid/DomPresenter.java b/src/fr/devinsy/xid/DomPresenter.java
index 4de127d..cd678a4 100644
--- a/src/fr/devinsy/xid/DomPresenter.java
+++ b/src/fr/devinsy/xid/DomPresenter.java
@@ -94,29 +94,29 @@ public class DomPresenter extends Presenter
 	/*
 	 *
 	 */
-	public StringBuffer doXid (Data datas, StringBuffer errorOutput)
+	public StringBuffer doXid (Data datas) throws Exception
 	{
-		return (doXid (datas.getIdsDataById (), errorOutput));
+		return (doXid (datas.getIdsDataById ()));
 	}
 
 	/*
 	 *
 	 */
-	public StringBuffer doXid (IdsDataById datas, StringBuffer errorOutput)
+	public StringBuffer doXid (IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
 		if (this.doc == null)
 		{
 			String errorMessage = "source not defined";
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 		else
 		{
 			// Build the web page.
-			result = Presenter.doXid (this.doc, datas, errorOutput);
+			result = Presenter.doXid (this.doc, datas);
 		}
 
 		//
@@ -127,11 +127,11 @@ public class DomPresenter extends Presenter
 	/*
 	 * Xid a file with data.
 	 */
-	static public StringBuffer doXid (Document doc, IdsDataById datas, String webappPath, StringBuffer errorOutput)
+	static public StringBuffer doXid (Document doc, IdsDataById datas, String webappPath) throws Exception
 	{
 		StringBuffer result;
 
-		result = Presenter.process (doc, datas, webappPath, errorOutput);
+		result = Presenter.process (doc, datas, webappPath);
 
 		//
 		return (result);
diff --git a/src/fr/devinsy/xid/FilePresenter.java b/src/fr/devinsy/xid/FilePresenter.java
index 8f7b864..ceb9585 100644
--- a/src/fr/devinsy/xid/FilePresenter.java
+++ b/src/fr/devinsy/xid/FilePresenter.java
@@ -68,16 +68,16 @@ public class FilePresenter extends DomPresenter
 	/*
 	 *
 	 */
-	public StringBuffer doXid (Data datas, StringBuffer errorOutput)
+	public StringBuffer doXid (Data datas) throws Exception
 	{
-		return (doXid (datas.getIdsDataById (), errorOutput));
+		return (doXid (datas.getIdsDataById ()));
 	}
 
 
 	/*
 	 *
 	 */
-	public StringBuffer doXid (IdsDataById datas, StringBuffer errorOutput)
+	public StringBuffer doXid (IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
@@ -89,22 +89,22 @@ public class FilePresenter extends DomPresenter
 		if (source == null)
 		{
 			String errorMessage = "source file not defined";
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 		else if (!source.exists ())
 		{
 			String errorMessage = "source file defined but not found (" + sourceFilePath + ")";
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 		else if ((this.doc == null) ||
 				(this.sourceFileTime != source.lastModified ()))
 		{
 			this.sourceFileTime = source.lastModified ();
-			this.doc = Presenter.fileToTree (sourceFilePath, errorOutput);
+			this.doc = Presenter.fileToTree (sourceFilePath);
 
 			if (this.doc != null)
 			{
@@ -113,7 +113,7 @@ public class FilePresenter extends DomPresenter
 		}
 
 		// Build the web page.
-		result = Presenter.doXid (doc, datas, errorOutput);
+		result = Presenter.doXid (doc, datas);
 
 		//
 		return (result);
@@ -123,11 +123,11 @@ public class FilePresenter extends DomPresenter
 	/*
 	 * Xid a file without data.
 	 */
-	static public StringBuffer doXid (String fileName, StringBuffer errorOutput)
+	static public StringBuffer doXid (String fileName) throws Exception
 	{
 		StringBuffer result;
 
-		Document doc = Presenter.fileToTree (fileName, errorOutput);
+		Document doc = Presenter.fileToTree (fileName);
 
 		if (doc == null)
 		{
@@ -137,7 +137,7 @@ public class FilePresenter extends DomPresenter
 		{
 			Presenter.addMetaTag (doc, "generator", "XID 0.0");
 
-			result = Presenter.doXid (doc, null, errorOutput);
+			result = Presenter.doXid (doc, null);
 		}
 
 		//
diff --git a/src/fr/devinsy/xid/Presenter.java b/src/fr/devinsy/xid/Presenter.java
index be50a68..f71d009 100644
--- a/src/fr/devinsy/xid/Presenter.java
+++ b/src/fr/devinsy/xid/Presenter.java
@@ -14,6 +14,7 @@ import org.w3c.dom.*;
 public class Presenter
 {
 	static final public char INDEX_SEPARATOR = '_';
+	static protected int bufferSize = 2048;
 
 	static protected org.apache.log4j.Logger logger;
 	static
@@ -25,17 +26,42 @@ public class Presenter
 	/*
 	 * Xid a file with data.
 	 */
-	static public StringBuffer doXid (Document doc, IdsDataById datas, StringBuffer errorOutput)
+	static public StringBuffer doXid (Document doc, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
-		result = Presenter.process (doc, datas, errorOutput);
+		result = Presenter.process (doc, datas);
 
 		//
 		return (result);
 	}
 
+	
+	/*
+	 *
+	 */
+	static public int bufferSize()
+	{
+		int result;
+		
+		result = bufferSize;
+		
+		//
+		return(result);
+	}
+	
 
+	/*
+	 *
+	 */
+	static public void setBufferSize(int value)
+	{
+		if (bufferSize > 0)
+		{
+			bufferSize = value;
+		}
+	}
+	
 	/*
 	 *
 	 */
@@ -117,11 +143,11 @@ public class Presenter
 	/*
 	 *
 	 */
-	static protected StringBuffer processChildren (Node node, IdsDataById datas, StringBuffer errorOutput)
+	static protected StringBuffer processChildren (Node node, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
-		result = processChildren (node, datas, "", errorOutput);
+		result = processChildren (node, datas, "");
 
 		//
 		return (result);
@@ -133,8 +159,7 @@ public class Presenter
 	 */
 	static protected StringBuffer processChildren (Node node,
 												   IdsDataById datas,
-												   String suffix,
-												   StringBuffer errorOutput)
+												   String suffix) throws Exception
 	{
 		StringBuffer result;
 		result = new StringBuffer ();
@@ -190,12 +215,12 @@ public class Presenter
 						lineCounter += 1;
 						if (lineCounter == 1)
 						{
-							result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+							result.append (process (children.item (childIndex), datas, suffix));
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+						result.append (process (children.item (childIndex), datas, suffix));
 					}	    
 				}
 				break;
@@ -210,12 +235,12 @@ public class Presenter
 	
 						if ((lineCounter == 1) || (lineCounter == 2))
 						{
-							result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+							result.append (process (children.item (childIndex), datas, suffix));
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+						result.append (process (children.item (childIndex), datas, suffix));
 					}
 				}
 				break;
@@ -230,12 +255,12 @@ public class Presenter
 						if ((attrs2 != null) &&
 								(attrs2.getNamedItem ("id") != null))
 						{
-							result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+							result.append (process (children.item (childIndex), datas, suffix));
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+						result.append (process (children.item (childIndex), datas, suffix));
 					}
 				}
 				break;
@@ -249,12 +274,12 @@ public class Presenter
 						if ((attrs2 == null) ||
 								(attrs2.getNamedItem ("id") == null))
 						{
-							result.append (process (children.item(childIndex), datas, suffix, errorOutput));
+							result.append (process (children.item(childIndex), datas, suffix));
 						}
 					}
 					else
 					{
-						result.append (process (children.item (childIndex), datas, suffix, errorOutput));
+						result.append (process (children.item (childIndex), datas, suffix));
 					}
 				}
 				break;
@@ -262,7 +287,7 @@ public class Presenter
 			case ALL_ROWS:
 				for (int childIndex = 0; childIndex < childrenCount; childIndex++)
 				{
-					result.append (process (children.item(childIndex), datas, suffix, errorOutput));
+					result.append (process (children.item(childIndex), datas, suffix));
 				}
 				break;
 		}
@@ -286,13 +311,12 @@ public class Presenter
 	static protected StringBuffer processElementWithId (Node node,
 														NamedNodeMap attrs,
 														Node idAttr,
-														IdsDataById datas,
-														StringBuffer errorOutput)
+														IdsDataById datas) throws Exception
 
 	{
 		StringBuffer result;
 
-		result = processElementWithId (node, attrs, idAttr, datas, "", errorOutput);
+		result = processElementWithId (node, attrs, idAttr, datas, "");
 
 		//
 		return (result);
@@ -311,11 +335,10 @@ public class Presenter
 	 *            The ID.
 	 */
 	static protected StringBuffer processElementWithId (Node node,
-			NamedNodeMap attrs,
-			Node idAttr,
-			IdsDataById datas,
-			String suffix,
-			StringBuffer errorOutput)
+														NamedNodeMap attrs,
+														Node idAttr,
+														IdsDataById datas,
+														String suffix) throws Exception
 	{
 		StringBuffer result;
 		result = new StringBuffer ();
@@ -331,7 +354,7 @@ public class Presenter
 
 		if (dataCore == null)
 		{
-			result.append (Presenter.processElementBasically (node, datas, suffix, errorOutput));
+			result.append (Presenter.processElementBasically (node, datas, suffix));
 		}
 		else if (dataCore instanceof IdData)
 		{
@@ -373,7 +396,7 @@ public class Presenter
 					if ((data == null) ||
 							(data.display () == null))
 					{
-						result.append (processChildren (node, datas, suffix, errorOutput));
+						result.append (processChildren (node, datas, suffix));
 					}
 					else
 					{
@@ -420,7 +443,7 @@ public class Presenter
 						// Insert data.
 						if ((data == null) || (data.display () == null))
 						{
-							result.append (processChildren (node, datas, suffix, errorOutput));
+							result.append (processChildren (node, datas, suffix));
 						}
 						else
 						{
@@ -438,7 +461,7 @@ public class Presenter
 					// Manage a Hashmap.
 					IdsDataById data = (IdsDataById) tags.elementAt (nLine);
 
-					result.append (Presenter.processElementWithId (node, attrs, idAttr, data, Integer.toString (nLine), errorOutput));
+					result.append (Presenter.processElementWithId (node, attrs, idAttr, data, Integer.toString (nLine)));
 					result.append ('\n');
 				}
 			}
@@ -458,11 +481,11 @@ public class Presenter
 	/**
 	 * 
 	 */
-	static protected StringBuffer process (Node node, IdsDataById datas, StringBuffer errorOutput)
+	static protected StringBuffer process (Node node, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
-		result = Presenter.process (node, datas, "", errorOutput);
+		result = Presenter.process (node, datas, "");
 
 		//
 		return (result);
@@ -473,7 +496,7 @@ public class Presenter
 	 * Recursive method that processes a node and any child nodes.
 	 * 
 	 */
-	static protected StringBuffer process (Node node, IdsDataById datas, String suffix, StringBuffer errorOutput)
+	static protected StringBuffer process (Node node, IdsDataById datas, String suffix) throws Exception
 	{
 		logger.debug ("process - started");
 		String TRANSITIONAL_DTD = "xhtml1-transitional.dtd";
@@ -517,7 +540,7 @@ public class Presenter
 							// Log.write(Log.TRACE,"systemId = " + systemId);
 						}
 	
-						result.append (Presenter.process (((Document) node).getDocumentElement(), datas, suffix, errorOutput));
+						result.append (Presenter.process (((Document) node).getDocumentElement(), datas, suffix));
 	
 						break;
 					}
@@ -535,12 +558,11 @@ public class Presenter
 																		   attrs,
 																		   idAttr,
 																		   datas,
-																		   suffix,
-																		   errorOutput));
+																		   suffix));
 						}
 						else
 						{
-							result.append (Presenter.processElementBasically (node, datas, suffix, errorOutput));
+							result.append (Presenter.processElementBasically (node, datas, suffix));
 						}
 	
 						break;
@@ -607,11 +629,11 @@ public class Presenter
 	/*
 	 *
 	 */
-	static StringBuffer processElementBasically (Node node, IdsDataById datas,StringBuffer errorOutput)
+	static StringBuffer processElementBasically (Node node, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
-		result = processElementBasically (node, datas, "", errorOutput);
+		result = processElementBasically (node, datas, "");
 
 		//
 		return (result);
@@ -621,7 +643,7 @@ public class Presenter
 	/*
 	 *
 	 */
-	static StringBuffer processElementBasically (Node node, IdsDataById datas, String suffix, StringBuffer errorOutput)
+	static StringBuffer processElementBasically (Node node, IdsDataById datas, String suffix) throws Exception
 	{
 		StringBuffer result;
 		logger.debug("processElementBasically - started");
@@ -648,7 +670,7 @@ public class Presenter
 		{
 			result.append('>');
 
-			result.append (processChildren (node, datas, suffix, errorOutput));
+			result.append (processChildren (node, datas, suffix));
 
 			result.append("</");
 			result.append(node.getNodeName());
@@ -666,7 +688,7 @@ public class Presenter
 	/*
 	 *
 	 */
-	static protected Document buildTree (InputStream source, StringBuffer errorOutput)
+	static protected Document buildTree (InputStream source) throws Exception
 	{
 		Document result;
 
@@ -699,36 +721,38 @@ public class Presenter
 
 			// Parse the input file.
 			result = db.parse (source);
-
+System.out.println("ZO4");
 			if (errorHandler.hasError ())
 			{
-				errorOutput.append (errorHandler.toString ());
+				System.out.println("ZO4a");
+				throw new Exception (errorHandler.toString ());
 			}
 			else
-			{
+			{System.out.println("ZO4b");
 				DomPresenter.addMetaTag (result, "generator", "XID 0.0");
 			}
+System.out.println("ZO5");
 		}
 		catch (ParserConfigurationException exception)
 		{
 			String errorMessage = "Parser configuration exception: " + exception.getMessage ();
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 		catch (SAXException exception)
 		{
 			String errorMessage = "Error during SAX parsing: " + exception.getMessage ();
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 		catch (IOException exception)
 		{
 			String errorMessage = "IOError during parsing." + exception.getMessage ();
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage);
 		}
 
 		//
@@ -737,7 +761,6 @@ public class Presenter
 
 
 
-
 	/*
 	 *
 	 */
@@ -1082,20 +1105,20 @@ public class Presenter
 	/*
 	 * Define in Presnter cause <object> needs this possibility.
 	 */
-	static protected Document fileToTree (String fileName, StringBuffer errorOutput)
+	static protected Document fileToTree (String fileName) throws Exception
 	{
 		Document result;
 
 		try
 		{
-			result = buildTree (new FileInputStream (new File (fileName)), errorOutput);
+			result = buildTree (new FileInputStream (new File (fileName)));
 		}
 		catch (IOException exception)
 		{
 			String errorMessage = "IOError during parsing." + exception.getMessage ();
-			errorOutput.append (errorMessage);
 			logger.error (errorMessage);
 			result = null;
+			throw new Exception (errorMessage, exception);
 		}
 
 		//
diff --git a/src/fr/devinsy/xid/StringPresenter.java b/src/fr/devinsy/xid/StringPresenter.java
index a49104f..b2e14f0 100644
--- a/src/fr/devinsy/xid/StringPresenter.java
+++ b/src/fr/devinsy/xid/StringPresenter.java
@@ -65,15 +65,15 @@ public class StringPresenter extends DomPresenter
 	/*
 	 *
 	 */
-	public StringBuffer doXid (Data datas, StringBuffer errorOutput)
+	public StringBuffer doXid (Data datas) throws Exception
 	{
-		return (doXid (datas.getIdsDataById (), errorOutput));
+		return (doXid (datas.getIdsDataById ()));
 	}
 
 	/*
 	 *
 	 */
-	public StringBuffer doXid (IdsDataById datas, StringBuffer errorOutput)
+	public StringBuffer doXid (IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
@@ -82,9 +82,9 @@ public class StringPresenter extends DomPresenter
 			// Build doc from this.html.
 			String htmlSource;
 			if ((this.html.startsWith ("<!DOCTYPE")) ||
-					(this.html.startsWith ("<!doctype")) ||
-					(this.html.startsWith ("<html>")) ||
-					(this.html.startsWith ("<HTML>")))
+				(this.html.startsWith ("<!doctype")) ||
+				(this.html.startsWith ("<html>")) ||
+				(this.html.startsWith ("<HTML>")))
 			{
 				htmlSource = html;
 			}
@@ -95,11 +95,11 @@ public class StringPresenter extends DomPresenter
 
 			// StringBufferInputStream is deprecated so we use another solution.
 			// (see http://www.developpez.net/forums/archive/index.php/t-14101.html).
-			doc = buildTree (new ByteArrayInputStream (htmlSource.getBytes ()), errorOutput);
+			doc = buildTree (new ByteArrayInputStream (htmlSource.getBytes ()));
 		}
 
 		StringBuffer htmlTarget;
-		htmlTarget = Presenter.doXid (doc, datas, errorOutput);
+		htmlTarget = Presenter.doXid (doc, datas);
 
 		if (htmlTarget == null)
 		{
@@ -134,22 +134,22 @@ public class StringPresenter extends DomPresenter
 	/*
 	 *
 	 */
-	static public StringBuffer doXid (String html, Data datas, StringBuffer errorOutput)
+	static public StringBuffer doXid (String html, Data datas) throws Exception
 	{
-		return (doXid (html, datas.getIdsDataById (), errorOutput));
+		return (doXid (html, datas.getIdsDataById ()));
 	}
 
 
 	/*
 	 * Xid a string with html in.
 	 */
-	static public StringBuffer doXid (String html, IdsDataById datas, StringBuffer errorOutput)
+	static public StringBuffer doXid (String html, IdsDataById datas) throws Exception
 	{
 		StringBuffer result;
 
 		StringPresenter presenter = new StringPresenter (html);
 
-		result = presenter.doXid (datas, errorOutput);
+		result = presenter.doXid (datas);
 
 		//
 		return (result);