// Copyright 2006 The Apache Software Foundation
//
// 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 implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry.ioc.internal.services;
import java.util.Map;
import org.apache.tapestry.ioc.ObjectProvider;
import org.apache.tapestry.ioc.ServiceLocator;
import org.apache.tapestry.ioc.internal.util.CollectionFactory;
import org.apache.tapestry.ioc.services.SymbolSource;
import org.apache.tapestry.ioc.services.TypeCoercer;
/**
* Master implementation of {@link org.apache.tapestry.ioc.ObjectProvider} that delegates out to
* specific implementations of ObjectProvider. This class enapsulates the logic for extracting a
* provider prefix, and using it to locate a specific instance, from the service's configuration.
*/
public class MasterObjectProvider implements ObjectProvider
{
private final Map<String, ObjectProvider> _configuration;
private final SymbolSource _symbolSource;
private final TypeCoercer _typeCoercer;
public MasterObjectProvider(Map<String, ObjectProvider> configuration,
SymbolSource symbolSource, TypeCoercer typeCoercer)
{
_configuration = CollectionFactory.newCaseInsensitiveMap(configuration);
_symbolSource = symbolSource;
_typeCoercer = typeCoercer;
}
/**
* The first parameter here isn't just an expression, its the entire object reference, including
* the prefix (and the colon separator).
*/
public <T> T provide(String reference, Class<T> objectType, ServiceLocator locator)
{
String expanded = _symbolSource.expandSymbols(reference);
int colonx = expanded.indexOf(':');
if (colonx < 0) { return _typeCoercer.coerce(expanded, objectType); }
String prefix = expanded.substring(0, colonx);
ObjectProvider provider = _configuration.get(prefix);
if (provider == null)
throw new RuntimeException(ServiceMessages.unknownObjectProvider(prefix, expanded));
String expression = expanded.substring(colonx + 1);
return provider.provide(expression, objectType, locator);
}
}