diff -r 000000000000 -r fb9019fb1bf7 src/net/fortuna/ical4j/model/component/Available.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/net/fortuna/ical4j/model/component/Available.java	Tue Feb 10 18:12:00 2015 +0100
@@ -0,0 +1,185 @@
+/**
+ * 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.component;
+
+import net.fortuna.ical4j.model.Component;
+import net.fortuna.ical4j.model.Parameter;
+import net.fortuna.ical4j.model.Property;
+import net.fortuna.ical4j.model.PropertyList;
+import net.fortuna.ical4j.model.ValidationException;
+import net.fortuna.ical4j.model.parameter.Value;
+import net.fortuna.ical4j.model.property.DtEnd;
+import net.fortuna.ical4j.model.property.DtStart;
+import net.fortuna.ical4j.util.PropertyValidator;
+
+/**
+ * $Id$ [05-Apr-2004]
+ *
+ * Defines an iCalendar Available component.
+ *
+ * <pre>
+ *
+ *       availablec  = &quot;BEGIN&quot; &quot;:&quot; &quot;AVAILABLE&quot; CRLF
+ *
+ *                    availableprop
+ *
+ *                    &quot;END&quot; &quot;:&quot; &quot;AVAILABLE&quot; CRLF
+ *
+          availableprop  = *(
+
+                         ; the following are REQUIRED,
+                         ; but MUST NOT occur more than once
+
+                         dtstamp / dtstart / uid /
+
+                         ; either a 'dtend' or a 'duration' is required
+                         ; in a 'availableprop', but 'dtend' and
+                         ; 'duration' MUST NOT occur in the same
+                         ; 'availableprop', and each MUST NOT occur more
+                         ; than once
+
+                         dtend / duration /
+
+                         ; the following are OPTIONAL,
+                         ; but MUST NOT occur more than once
+
+                         created / last-mod / recurid / rrule /
+                         summary /
+
+                         ; the following are OPTIONAL,
+                         ; and MAY occur more than once
+
+                         categories / comment / contact / exdate /
+                         rdate / x-prop
+
+                         )
+ * </pre>
+ *
+ * @author Ben Fortuna
+ * @author Mike Douglass
+ */
+public class Available extends Component {
+
+    private static final long serialVersionUID = -2494710612002978763L;
+
+    /**
+     * Default constructor.
+     */
+    public Available() {
+        super(AVAILABLE);
+    }
+
+    /**
+     * Constructor.
+     * @param properties a list of properties
+     */
+    public Available(final PropertyList properties) {
+        super(AVAILABLE, properties);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public final void validate(final boolean recurse)
+            throws ValidationException {
+
+        /*
+         * ; dtstamp / dtstart / uid are required, but MUST NOT occur more than once /
+         */
+        PropertyValidator.getInstance().assertOne(Property.DTSTART,
+                getProperties());
+        PropertyValidator.getInstance().assertOne(Property.DTSTAMP,
+                getProperties());
+        PropertyValidator.getInstance().assertOne(Property.UID,
+                getProperties());
+
+        /*       If specified, the "DTSTART" and "DTEND" properties in
+         *      "VAVAILABILITY" components and "AVAILABLE" sub-components MUST be
+         *      "DATE-TIME" values specified as either date with UTC time or date
+         *      with local time and a time zone reference.
+         */
+        final DtStart start = (DtStart) getProperty(Property.DTSTART);
+        if (Value.DATE.equals(start.getParameter(Parameter.VALUE))) {
+            throw new ValidationException("Property [" + Property.DTSTART
+                    + "] must be a " + Value.DATE_TIME);
+        }
+
+        /*
+         *                ; the following are optional,
+         *                ; but MUST NOT occur more than once
+         *
+         *               created / last-mod / recurid / rrule /
+         *               summary /
+         */
+        PropertyValidator.getInstance().assertOneOrLess(Property.CREATED,
+                getProperties());
+        PropertyValidator.getInstance().assertOneOrLess(Property.LAST_MODIFIED,
+                getProperties());
+        PropertyValidator.getInstance().assertOneOrLess(Property.RECURRENCE_ID,
+                getProperties());
+        PropertyValidator.getInstance().assertOneOrLess(Property.RRULE,
+                getProperties());
+        PropertyValidator.getInstance().assertOneOrLess(Property.SUMMARY,
+                getProperties());
+
+        /*
+         ; either a 'dtend' or a 'duration' is required
+         ; in a 'availableprop', but 'dtend' and
+         ; 'duration' MUST NOT occur in the same
+         ; 'availableprop', and each MUST NOT occur more
+         ; than once
+         */
+        if (getProperty(Property.DTEND) != null) {
+            PropertyValidator.getInstance().assertOne(Property.DTEND,
+                    getProperties());
+            /* Must be DATE_TIME */
+            final DtEnd end = (DtEnd) getProperty(Property.DTEND);
+            if (Value.DATE.equals(end.getParameter(Parameter.VALUE))) {
+                throw new ValidationException("Property [" + Property.DTEND
+                        + "] must be a " + Value.DATE_TIME);
+            }
+        } else {
+            PropertyValidator.getInstance().assertOne(Property.DURATION,
+                    getProperties());
+        }
+
+        /*
+         * ; the following are optional, ; and MAY occur more than once
+         *               categories / comment / contact / exdate /
+         *               rdate / x-prop
+         */
+
+        if (recurse) {
+            validateProperties();
+        }
+    }
+}