001/**
002 * Copyright 2005-2016 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.rice.kew.validation;
017
018import org.apache.commons.lang.StringUtils;
019import org.kuali.rice.kew.api.WorkflowRuntimeException;
020import org.kuali.rice.kew.api.validation.RuleValidationContext;
021import org.kuali.rice.kew.api.validation.ValidationResults;
022import org.kuali.rice.kew.framework.KewFrameworkServiceLocator;
023import org.kuali.rice.kew.framework.validation.RuleValidationAttributeExporterService;
024import org.kuali.rice.kew.rule.RuleValidationAttribute;
025
026import java.lang.reflect.InvocationHandler;
027import java.lang.reflect.Method;
028import java.lang.reflect.Proxy;
029
030/**
031 * RuleValidationAttributeResolver reference impl.  Returns a proxy which delegates to the appropriate
032 * RuleValidationExporterService.
033 *
034 * @see org.kuali.rice.kew.rule.RuleValidationAttribute
035 * @see org.kuali.rice.kew.framework.validation.RuleValidationAttributeExporterService
036 * @author Kuali Rice Team (rice.collab@kuali.org)
037 */
038public class RuleValidationAttributeResolverImpl implements RuleValidationAttributeResolver {
039    @Override
040    public RuleValidationAttribute resolveRuleValidationAttribute(final String attributeName, String applicationId) throws Exception {
041        final RuleValidationAttributeExporterService service = findRuleValidationAttributeExporterService(applicationId);
042        return (RuleValidationAttribute) Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class<?>[] { RuleValidationAttribute.class }, new RuleValidationAttributeInvocationHandler() {
043            @Override
044            protected ValidationResults invokeValidate(RuleValidationContext context) throws Exception {
045                return service.validate(attributeName, context);
046            }
047        });
048    }
049
050    protected RuleValidationAttributeExporterService findRuleValidationAttributeExporterService(String applicationId) {
051        RuleValidationAttributeExporterService service = KewFrameworkServiceLocator.getRuleValidationAttributeExporterService(applicationId);
052        if (service == null) {
053            throw new WorkflowRuntimeException("Failed to locate RuleValidationAttributeExporterService for applicationId: " + applicationId);
054        }
055        return service;
056    }
057
058    protected static abstract class RuleValidationAttributeInvocationHandler implements InvocationHandler {
059        @Override
060        public ValidationResults invoke(Object o, Method method, Object[] objects) throws Throwable {
061            if (!StringUtils.equals(method.getName(), "validate")) {
062                throw new UnsupportedOperationException("RuleValidationAttribute only supports 'validate'");
063            }
064            return invokeValidate((RuleValidationContext) objects[0]);
065        }
066        protected abstract ValidationResults invokeValidate(RuleValidationContext context) throws Exception;
067    }
068}