/*

  * Copyright 2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl1.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.kns.datadictionary.validation;

 import java.util.List;

 import org.kuali.rice.kns.datadictionary.AttributeDefinition;

 import org.kuali.rice.kns.datadictionary.exception.AttributeValidationException;

 import org.kuali.rice.kns.datadictionary.validation.capability.Constrainable;

 import org.kuali.rice.kns.datadictionary.validation.constraint.DataTypeConstraint;

 /**

  * This class allows a single attribute value to be exposed to the validation service, along 

  * with some guidance about how that value should be interpreted, provided by the AttributeDefinition

  * that corresponds. It's a special AttributeValueReader since it explicitly doesn't expose any

  * other attribute values, so it should only be used when the underlying business object is not available

  * and we want to limit access to (for example) validation that requires only a single attribute value. 

  * This eliminates more complicated validation like 'this field is required when another field is filled in.'

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org) 

  */

 public class SingleAttributeValueReader extends BaseAttributeValueReader {

         private Object value;

         private AttributeDefinition definition;

         public SingleAttributeValueReader(Object value, String entryName, String attributeName, AttributeDefinition definition) {

                 this.value = value;

                 this.entryName = entryName;

                 this.attributeName = attributeName;

                 this.definition = definition;

         }

         @Override

         public Constrainable getDefinition(String attributeName) {

                 // Only return the definition if you have it, and if it's the definition for the passed attribute name

                 return definition != null && definition.getName() != null && definition.getName().equals(attributeName) ? definition : null;

         }

         @Override

         public List<Constrainable> getDefinitions() {

                 return null;

         }

         /**

          * @see org.kuali.rice.kns.datadictionary.validation.AttributeValueReader#getEntry()

          */

         @Override

         public Constrainable getEntry() {

                 return null;

         }

         @Override

         public String getLabel(String attributeName) {

                 if (definition != null && definition.getName() != null && definition.getName().equals(attributeName))

                         return definition.getLabel();

                 return attributeName;

         }

         @Override

         public Object getObject() {

                 return null;

         }

         @Override

         public String getPath() {

                 return attributeName;

         }

         @Override

         public Class<?> getType(String selectedAttributeName) {

                 Constrainable attributeDefinition = getDefinition(selectedAttributeName);

                 if (attributeDefinition != null && attributeDefinition instanceof DataTypeConstraint) {

                         DataTypeConstraint dataTypeConstraint = (DataTypeConstraint)attributeDefinition;

                         if (dataTypeConstraint.getDataType() != null)

                                 return dataTypeConstraint.getDataType().getType();

                 }

                 // Assuming we can reliably guess

                 return value != null ? value.getClass() : null;

         }

         @Override

         public <X> X getValue() throws AttributeValidationException {

                 return (X) value;

         }

         @Override

         public <X> X getValue(String attributeName) throws AttributeValidationException {

                 Constrainable attributeDefinition = getDefinition(attributeName);

                 if (attributeDefinition != null)

                         return (X) value;

                 return null;

         }

 }