michael@0: /**
michael@0:  * Copyright (c) 2012, Ben Fortuna
michael@0:  * All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  *
michael@0:  *  o Redistributions of source code must retain the above copyright
michael@0:  * notice, this list of conditions and the following disclaimer.
michael@0:  *
michael@0:  *  o Redistributions in binary form must reproduce the above copyright
michael@0:  * notice, this list of conditions and the following disclaimer in the
michael@0:  * documentation and/or other materials provided with the distribution.
michael@0:  *
michael@0:  *  o Neither the name of Ben Fortuna nor the names of any other contributors
michael@0:  * may be used to endorse or promote products derived from this software
michael@0:  * without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0:  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0:  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0:  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
michael@0:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
michael@0:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
michael@0:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
michael@0:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
michael@0:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
michael@0:  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
michael@0:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: package net.fortuna.ical4j.util;
michael@0: 
michael@0: import net.fortuna.ical4j.model.Parameter;
michael@0: import net.fortuna.ical4j.model.ParameterList;
michael@0: import net.fortuna.ical4j.model.ValidationException;
michael@0: 
michael@0: /**
michael@0:  * $Id$ [15-May-2004]
michael@0:  *
michael@0:  * Defines methods for validating parameters and parameter
michael@0:  * lists.
michael@0:  * 
michael@0:  * @author Ben Fortuna
michael@0:  */
michael@0: public final class ParameterValidator {
michael@0: 
michael@0:     private static final String ASSERT_NONE_MESSAGE = "Parameter [{0}] is not applicable";
michael@0: 
michael@0:     private static final String ASSERT_ONE_OR_LESS_MESSAGE = "Parameter [{0}] must only be specified once";
michael@0: 
michael@0:     private static final String ASSERT_ONE_MESSAGE = "Parameter [{0}] must be specified once";
michael@0: 
michael@0:     private static final String ASSERT_NULL_OR_EQUAL_MESSAGE = "Parameter [{0}] is invalid";
michael@0: 
michael@0:     private static ParameterValidator instance = new ParameterValidator();
michael@0: 
michael@0:     /**
michael@0:      * Constructor made private to enforce singleton.
michael@0:      */
michael@0:     private ParameterValidator() {
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Ensure a parameter occurs no more than once.
michael@0:      *
michael@0:      * @param paramName
michael@0:      *            the parameter name
michael@0:      * @param parameters
michael@0:      *            a list of parameters to query
michael@0:      * @throws ValidationException
michael@0:      *             when the specified parameter occurs more than once
michael@0:      */
michael@0:     public void assertOneOrLess(final String paramName,
michael@0:             final ParameterList parameters) throws ValidationException {
michael@0: 
michael@0:         if (parameters.getParameters(paramName).size() > 1) {
michael@0:             throw new ValidationException(ASSERT_ONE_OR_LESS_MESSAGE, new Object[] {paramName});
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Ensure a parameter occurs once.
michael@0:      *
michael@0:      * @param paramName
michael@0:      *            the parameter name
michael@0:      * @param parameters
michael@0:      *            a list of parameters to query
michael@0:      * @throws ValidationException
michael@0:      *             when the specified parameter does not occur once
michael@0:      */
michael@0:     public void assertOne(final String paramName,
michael@0:             final ParameterList parameters) throws ValidationException {
michael@0: 
michael@0:         if (parameters.getParameters(paramName).size() != 1) {
michael@0:             throw new ValidationException(ASSERT_ONE_MESSAGE, new Object[] {paramName});
michael@0:         }
michael@0:     }
michael@0:     
michael@0:     /**
michael@0:      * Ensure a parameter doesn't occur in the specified list.
michael@0:      * @param paramName the name of a parameter
michael@0:      * @param parameters a list of parameters
michael@0:      * @throws ValidationException thrown when the specified property
michael@0:      * is found in the list of properties
michael@0:      */
michael@0:     public void assertNone(final String paramName, final ParameterList parameters) throws ValidationException {
michael@0:         if (parameters.getParameter(paramName) != null) {
michael@0:             throw new ValidationException(ASSERT_NONE_MESSAGE, new Object[] {paramName});
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * @param param a parameter instance
michael@0:      * @param parameters a list of parameters
michael@0:      * @throws ValidationException where the assertion fails
michael@0:      */
michael@0:     public void assertNullOrEqual(final Parameter param, final ParameterList parameters) throws ValidationException {
michael@0:         final Parameter p = parameters.getParameter(param.getName());
michael@0:         if (p != null && !param.equals(p)) {
michael@0:             throw new ValidationException(ASSERT_NULL_OR_EQUAL_MESSAGE, new Object[] {p});
michael@0:         }
michael@0:     }
michael@0:     
michael@0:     /**
michael@0:      * @return Returns the instance.
michael@0:      */
michael@0:     public static ParameterValidator getInstance() {
michael@0:         return instance;
michael@0:     }
michael@0: }