001// Copyright 2004, 2005 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.hivemind.lib;
016
017/**
018 * Service interface for a source of beans of a particular type.
019 * Bean instances are retrieved using a <em>locator string</em> which is of the form:
020 * <code><em>name</em>[,<em>initializer</em>]</code>.  That is, an optional initializer is
021 * may be specified, separated by a comma.
022 * 
023 * <p>
024 * Beans may be cached or not.
025 * 
026 * <p>
027 * The <code>hivemind.lib.BeanFactoryBuilder</code> service is used to create services
028 * implementing this interface (driven from a configuration).
029 *
030 * @author Howard Lewis Ship
031 */
032public interface BeanFactory
033{
034    /**
035     * Returns true if a bean matching the provided locator has been
036     * defined.
037     * 
038     * @param locator the name or name and initializer
039     * @return true if a bean matching the provided locator has ben defined
040     */
041    public boolean contains(String locator);
042    
043    /**
044     * Gets a bean via its locator (it's name plus, optionally, an initializer).
045     * 
046     * @param locator the name or name and initializer
047     * @return a bean instance
048     * @throws org.apache.hivemind.ApplicationRuntimeException if no bean matching the provided 
049     * name has been defined.
050     */
051    public Object get(String locator);
052}