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    1   /*
    2    * Copyright 2004-2009 the Seasar Foundation and the Others.
    3    *
    4    * Licensed under the Apache License, Version 2.0 (the "License");
    5    * you may not use this file except in compliance with the License.
    6    * You may obtain a copy of the License at
    7    *
    8    *     http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
    13   * either express or implied. See the License for the specific language
    14   * governing permissions and limitations under the License.
    15   */
    16  package org.seasar.cubby.plugins.guice;
    17
    18  import java.util.ArrayList;
    19  import java.util.List;
    20
    21  import javax.servlet.ServletContext;
    22  import javax.servlet.ServletContextEvent;
    23
    24  import org.slf4j.Logger;
    25  import org.slf4j.LoggerFactory;
    26
    27  import com.google.inject.Guice;
    28  import com.google.inject.Injector;
    29  import com.google.inject.Module;
    30  import com.google.inject.servlet.GuiceServletContextListener;
    31
    32  /**
    33   * {@link Injector} を初期化するための {@code Servlet} コンテキストのリスナです。
    34   * <p>
    35   * アプリケーションが使用するモジュールのクラス名を WEB 配備記述子の初期化パラメータ {@value #MODULE_INIT_PARAM_NAME}
    36   * に指定してください。
    37   * </p>
    38   * <p>
    39   * 例
    40   *
    41   * <pre>
    42   * &lt;context-param&gt;
    43   *   &lt;param-name&gt;{@value #MODULE_INIT_PARAM_NAME}&lt;/paanm-name&gt;
    44   *   &lt;param-value&gt;com.example.ApplicationModule&lt;/param-value&gt;
    45   * &lt;/context-param&gt;
    46   * </pre>
    47   *
    48   * </p>
    49   *
    50   * @author baba
    51   */
    52  public class CubbyGuiceServletContextListener extends
    53  		GuiceServletContextListener {
    54
    55  	private static final Logger logger = LoggerFactory
    56  			.getLogger(CubbyGuiceServletContextListener.class.getName());
    57
    58  	/** モジュールの WEB 配備記述子の初期化パラメータ名 */
    59  	public static final String MODULE_INIT_PARAM_NAME = "cubby.guice.module";
    60
    61  	/** インスタンス化するモジュールのクラス名 */
    62  	private String[] moduleClassNames;
    63
    64  	/**
    65  	 * {@inheritDoc}
    66  	 */
    67  	@Override
    68  	public void contextInitialized(ServletContextEvent servletContextEvent) {
    69  		final ServletContext servletContext = servletContextEvent
    70  				.getServletContext();
    71  		final String moduleClassNamesString = servletContext
    72  				.getInitParameter(MODULE_INIT_PARAM_NAME);
    73  		if (moduleClassNamesString == null
    74  				|| moduleClassNamesString.length() == 0) {
    75  			throw new IllegalArgumentException("No context parameter \""
    76  					+ MODULE_INIT_PARAM_NAME + "\", please set Module FQCN");
    77  		}
    78  		this.moduleClassNames = moduleClassNamesString.split(",");
    79
    80  		super.contextInitialized(servletContextEvent);
    81  	}
    82
    83  	/**
    84  	 * 指定されたクラス名のモジュールを生成します。
    85  	 *
    86  	 * @param moduleClassName
    87  	 *            モジュールのクラス名
    88  	 * @return インジェクタ
    89  	 */
    90  	protected Module createModule(final String moduleClassName) {
    91  		if (logger.isInfoEnabled()) {
    92  			logger.info("Instantiates " + moduleClassName);
    93  		}
    94
    95  		final ClassLoader loader = Thread.currentThread()
    96  				.getContextClassLoader();
    97  		try {
    98  			final Class<?> clazz = Class.forName(moduleClassName, true, loader);
    99  			final Module module = Module.class.cast(clazz.newInstance());
    100 			return module;
    101 		} catch (final ClassNotFoundException e) {
    102 			throw new IllegalArgumentException("Illegal module "
    103 					+ moduleClassName, e);
    104 		} catch (final InstantiationException e) {
    105 			throw new IllegalArgumentException("Illegal module "
    106 					+ moduleClassName, e);
    107 		} catch (final IllegalAccessException e) {
    108 			throw new IllegalArgumentException("Illegal module "
    109 					+ moduleClassName, e);
    110 		}
    111 	}
    112
    113 	/**
    114 	 * {@inheritDoc}
    115 	 */
    116 	@Override
    117 	protected Injector getInjector() {
    118 		final List<Module> modules = new ArrayList<Module>();
    119 		for (final String moduleClassName : this.moduleClassNames) {
    120 			final Module module = createModule(moduleClassName.trim());
    121 			modules.add(module);
    122 		}
    123 		return Guice.createInjector(modules);
    124 	}
    125
    126 }