| /* |
| * Copyright 2007-2011 Rickard Öberg. |
| * Copyright 2007-2010 Niclas Hedhman. |
| * |
| * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0 |
| * |
| * 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 |
| * ied. |
| * |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.zest.api.query.grammar; |
| |
| import java.lang.reflect.AccessibleObject; |
| import java.lang.reflect.Member; |
| import java.lang.reflect.Proxy; |
| import java.lang.reflect.Type; |
| import org.apache.zest.api.association.Association; |
| import org.apache.zest.api.association.AssociationStateHolder; |
| import org.apache.zest.api.association.GenericAssociationInfo; |
| import org.apache.zest.api.association.ManyAssociation; |
| import org.apache.zest.api.association.NamedAssociation; |
| import org.apache.zest.api.composite.Composite; |
| import org.apache.zest.api.composite.CompositeInstance; |
| import org.apache.zest.api.query.QueryExpressionException; |
| import org.apache.zest.api.util.Classes; |
| import org.apache.zest.functional.Function; |
| |
| import static org.apache.zest.api.util.Classes.typeOf; |
| |
| /** |
| * Function to get Entity Associations |
| */ |
| public class AssociationFunction<T> |
| implements Function<Composite, Association<T>> |
| { |
| private final AssociationFunction<?> traversedAssociation; |
| private final ManyAssociationFunction<?> traversedManyAssociation; |
| private final NamedAssociationFunction<?> traversedNamedAssociation; |
| private final AccessibleObject accessor; |
| |
| public AssociationFunction( AssociationFunction<?> traversedAssociation, |
| ManyAssociationFunction<?> traversedManyAssociation, |
| NamedAssociationFunction<?> traversedNamedAssociation, |
| AccessibleObject accessor |
| ) |
| { |
| this.traversedAssociation = traversedAssociation; |
| this.traversedManyAssociation = traversedManyAssociation; |
| this.traversedNamedAssociation = traversedNamedAssociation; |
| this.accessor = accessor; |
| |
| Type returnType = typeOf( accessor ); |
| if( !Association.class.isAssignableFrom( Classes.RAW_CLASS.map( returnType ) ) |
| && !ManyAssociation.class.isAssignableFrom( Classes.RAW_CLASS.map( returnType ) ) |
| && !NamedAssociation.class.isAssignableFrom( Classes.RAW_CLASS.map( returnType ) ) ) |
| { |
| throw new QueryExpressionException( "Unsupported association type:" + returnType ); |
| } |
| Type associationTypeAsType = GenericAssociationInfo.toAssociationType( returnType ); |
| if( !( associationTypeAsType instanceof Class ) ) |
| { |
| throw new QueryExpressionException( "Unsupported association type:" + associationTypeAsType ); |
| } |
| } |
| |
| public AssociationFunction<?> traversedAssociation() |
| { |
| return traversedAssociation; |
| } |
| |
| public ManyAssociationFunction<?> traversedManyAssociation() |
| { |
| return traversedManyAssociation; |
| } |
| |
| public NamedAssociationFunction<?> traversedNamedAssociation() |
| { |
| return traversedNamedAssociation; |
| } |
| |
| public AccessibleObject accessor() |
| { |
| return accessor; |
| } |
| |
| @Override |
| public Association<T> map( Composite entity ) |
| { |
| try |
| { |
| Object target = entity; |
| if( traversedAssociation != null ) |
| { |
| Association<?> association = traversedAssociation.map( entity ); |
| if( association == null ) |
| { |
| return null; |
| } |
| target = association.get(); |
| } |
| else if( traversedManyAssociation != null ) |
| { |
| throw new IllegalArgumentException( "Cannot evaluate a ManyAssociation" ); |
| } |
| else if( traversedNamedAssociation != null ) |
| { |
| throw new IllegalArgumentException( "Cannot evaluate a NamedAssociation" ); |
| } |
| |
| if( target == null ) |
| { |
| return null; |
| } |
| |
| CompositeInstance handler = (CompositeInstance) Proxy.getInvocationHandler( target ); |
| return ( (AssociationStateHolder) handler.state() ).associationFor( accessor ); |
| } |
| catch( IllegalArgumentException e ) |
| { |
| throw e; |
| } |
| catch( Throwable e ) |
| { |
| throw new IllegalArgumentException( e ); |
| } |
| } |
| |
| @Override |
| public String toString() |
| { |
| if( traversedAssociation != null ) |
| { |
| return traversedAssociation.toString() + "." + ( (Member) accessor ).getName(); |
| } |
| else |
| { |
| return ( (Member) accessor ).getName(); |
| } |
| } |
| } |