001// Copyright 2006, 2007, 2008, 2009, 2010, 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.ioc.internal;
016
017import org.apache.tapestry5.commons.ObjectLocator;
018import org.apache.tapestry5.commons.OrderedConfiguration;
019import org.apache.tapestry5.ioc.def.ContributionDef;
020import org.apache.tapestry5.ioc.internal.util.InternalUtils;
021import org.apache.tapestry5.ioc.internal.util.Orderer;
022
023import java.util.Map;
024
025/**
026 * Wraps a {@link java.util.List} as a {@link org.apache.tapestry5.commons.OrderedConfiguration}, implementing validation of
027 * values provided to an {@link org.apache.tapestry5.commons.OrderedConfiguration}.
028 *
029 * @param <T>
030 */
031public class ValidatingOrderedConfigurationWrapper<T> extends AbstractConfigurationImpl<T> implements
032        OrderedConfiguration<T>
033{
034    private final TypeCoercerProxy typeCoercer;
035
036    private final Orderer<T> orderer;
037
038    private final Class<T> expectedType;
039
040    private final Map<String, OrderedConfigurationOverride<T>> overrides;
041
042    private final ContributionDef contribDef;
043
044    // Used to supply a default ordering constraint when none is supplied.
045    private String priorId;
046
047    public ValidatingOrderedConfigurationWrapper(Class<T> expectedType, ObjectLocator locator,
048                                                 TypeCoercerProxy typeCoercer, Orderer<T> orderer, Map<String, OrderedConfigurationOverride<T>> overrides,
049                                                 ContributionDef contribDef)
050    {
051        super(expectedType, locator);
052        this.typeCoercer = typeCoercer;
053
054        this.orderer = orderer;
055        this.overrides = overrides;
056        this.contribDef = contribDef;
057        this.expectedType = expectedType;
058    }
059
060    @Override
061    public void add(String id, T object, String... constraints)
062    {
063        T coerced = object == null ? null : typeCoercer.coerce(object, expectedType);
064
065        // https://issues.apache.org/jira/browse/TAP5-1565
066        // Order each added contribution after the previously added contribution
067        // (in the same method) if no other constraint is supplied.
068        if (constraints.length == 0 && priorId != null)
069        {
070            // Ugly: reassigning parameters is yuck.
071            constraints = new String[]{"after:" + priorId};
072        }
073
074        orderer.add(id, coerced, constraints);
075
076        priorId = id;
077    }
078
079    @Override
080    public void override(String id, T object, String... constraints)
081    {
082        assert InternalUtils.isNonBlank(id);
083
084        T coerced = object == null ? null : typeCoercer.coerce(object, expectedType);
085
086        OrderedConfigurationOverride<T> existing = overrides.get(id);
087
088        if (existing != null)
089            throw new IllegalArgumentException(String.format("Contribution '%s' has already been overridden (by %s).",
090                    id, existing.getContribDef()));
091
092        overrides.put(id, new OrderedConfigurationOverride<T>(orderer, id, coerced, constraints, contribDef));
093    }
094
095    @Override
096    public void addInstance(String id, Class<? extends T> clazz, String... constraints)
097    {
098        add(id, instantiate(clazz), constraints);
099    }
100
101    @Override
102    public void overrideInstance(String id, Class<? extends T> clazz, String... constraints)
103    {
104        override(id, instantiate(clazz), constraints);
105    }
106}