diff -r 000000000000 -r fb9019fb1bf7 src/net/fortuna/ical4j/model/property/XProperty.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/net/fortuna/ical4j/model/property/XProperty.java	Tue Feb 10 18:12:00 2015 +0100
@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2012, Ben Fortuna
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  o Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ *  o Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ *  o Neither the name of Ben Fortuna nor the names of any other contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.fortuna.ical4j.model.property;
+
+import net.fortuna.ical4j.model.Escapable;
+import net.fortuna.ical4j.model.ParameterList;
+import net.fortuna.ical4j.model.Property;
+import net.fortuna.ical4j.model.PropertyFactoryImpl;
+import net.fortuna.ical4j.model.ValidationException;
+import net.fortuna.ical4j.util.CompatibilityHints;
+
+/**
+ * $Id$
+ * 
+ * Created: [15/06/2004]
+ *
+ * Defines an extension property.
+ * @author benfortuna
+ */
+public class XProperty extends Property implements Escapable {
+
+    private static final long serialVersionUID = 2331763266954894541L;
+
+    private String value;
+
+    /**
+     * Constructs an uninitialised non-standard property.
+     * @param name a non-standard property name
+     */
+    public XProperty(final String name) {
+        super(name, PropertyFactoryImpl.getInstance());
+    }
+
+    /**
+     * @param aName a non-standard property name
+     * @param aValue a property value
+     */
+    public XProperty(final String aName, final String aValue) {
+        super(aName, PropertyFactoryImpl.getInstance());
+        setValue(aValue);
+    }
+
+    /**
+     * @param aName a non-standard property name
+     * @param aList a list of parameters
+     * @param aValue a property value
+     */
+    public XProperty(final String aName, final ParameterList aList,
+            final String aValue) {
+        super(aName, aList, PropertyFactoryImpl.getInstance());
+        setValue(aValue);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public final void setValue(final String aValue) {
+        this.value = aValue;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public final String getValue() {
+        return value;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public final void validate() throws ValidationException {
+        
+        if (!CompatibilityHints.isHintEnabled(CompatibilityHints.KEY_RELAXED_VALIDATION)
+                && !getName().startsWith(EXPERIMENTAL_PREFIX)) {
+            
+            throw new ValidationException(
+                    "Invalid name ["
+                            + getName()
+                            + "]. Experimental properties must have the following prefix: "
+                            + EXPERIMENTAL_PREFIX);
+        }
+    }
+}