diff -r 5ae3e5665a0b -r cc93757aeca3 src/net/fortuna/ical4j/util/PropertyValidator.java
--- a/src/net/fortuna/ical4j/util/PropertyValidator.java	Thu Feb 12 18:02:00 2015 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,135 +0,0 @@
-/**
- * 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.util;
-
-import net.fortuna.ical4j.model.PropertyList;
-import net.fortuna.ical4j.model.ValidationException;
-
-/**
- * $Id$ [15-May-2004]
- *
- * Defines methods for validating properties and property lists.
- *
- * @author Ben Fortuna
- */
-public final class PropertyValidator {
-
-    private static final String ASSERT_NONE_MESSAGE = "Property [{0}] is not applicable";
-
-    private static final String ASSERT_ONE_OR_LESS_MESSAGE = "Property [{0}] must only be specified once";
-
-    private static final String ASSERT_ONE_MESSAGE = "Property [{0}] must be specified once";
-
-    private static final String ASSERT_ONE_OR_MORE_MESSAGE = "Property [{0}] must be specified at least once";
-
-    private static PropertyValidator instance = new PropertyValidator();
-
-    /**
-     * Constructor made private to enforce singleton.
-     */
-    private PropertyValidator() {
-    }
-
-    /**
-     * Ensure a property occurs no more than once.
-     *
-     * @param propertyName
-     *            the property name
-     * @param properties
-     *            a list of properties to query
-     * @throws ValidationException
-     *             when the specified property occurs more than once
-     */
-    public void assertOneOrLess(final String propertyName,
-            final PropertyList properties) throws ValidationException {
-
-        if (properties.getProperties(propertyName).size() > 1) {
-            throw new ValidationException(ASSERT_ONE_OR_LESS_MESSAGE, new Object[] {propertyName});
-        }
-    }
-
-    /**
-     * Ensure a property occurs at least once.
-     *
-     * @param propertyName
-     *            the property name
-     * @param properties
-     *            a list of properties to query
-     * @throws ValidationException
-     *             when the specified property occurs more than once
-     */
-    public void assertOneOrMore(final String propertyName,
-            final PropertyList properties) throws ValidationException {
-
-        if (properties.getProperties(propertyName).size() < 1) {
-            throw new ValidationException(ASSERT_ONE_OR_MORE_MESSAGE, new Object[] {propertyName});
-        }
-    }
-
-    /**
-     * Ensure a property occurs once.
-     *
-     * @param propertyName
-     *            the property name
-     * @param properties
-     *            a list of properties to query
-     * @throws ValidationException
-     *             when the specified property does not occur once
-     */
-    public void assertOne(final String propertyName,
-            final PropertyList properties) throws ValidationException {
-
-        if (properties.getProperties(propertyName).size() != 1) {
-            throw new ValidationException(ASSERT_ONE_MESSAGE, new Object[] {propertyName});
-        }
-    }
-    
-    /**
-     * Ensure a property doesn't occur in the specified list.
-     * @param propertyName the name of a property
-     * @param properties a list of properties
-     * @throws ValidationException thrown when the specified property
-     * is found in the list of properties
-     */
-    public void assertNone(final String propertyName, final PropertyList properties) throws ValidationException {
-        if (properties.getProperty(propertyName) != null) {
-            throw new ValidationException(ASSERT_NONE_MESSAGE, new Object[] {propertyName});
-        }
-    }
-
-    /**
-     * @return Returns the instance.
-     */
-    public static PropertyValidator getInstance() {
-        return instance;
-    }
-}