| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.commons.configuration2.builder.combined; |
| |
| import java.util.Collection; |
| |
| import org.apache.commons.configuration2.builder.BuilderParameters; |
| import org.apache.commons.configuration2.builder.FileBasedBuilderParametersImpl; |
| import org.apache.commons.configuration2.ex.ConfigurationException; |
| |
| /** |
| * <p> |
| * A specialized implementation of {@link ConfigurationBuilderProvider} which |
| * determines the name of the result configuration class based on the extension |
| * of the file to load. |
| * </p> |
| * <p> |
| * This class works analogously to its base class {@link BaseConfigurationBuilderProvider}; |
| * especially, the resulting builder is created based on reflection. It extends |
| * the super class's functionality by a specific mechanism for determining the |
| * resulting configuration class: At construction time two configuration class |
| * names and a file extension are passed in. If a file name is provided in the |
| * builder's initialization parameters and this file name has the specified |
| * extension, then the first configuration class name is used; otherwise the |
| * default configuration class name is selected. |
| * </p> |
| * <p> |
| * There are some tags for {@code CombinedConfigurationProvider} which can |
| * produce different results depending on the configuration files they have to |
| * load. This class can be used to implement this feature in a generic way. |
| * </p> |
| * |
| * @since 2.0 |
| */ |
| public class FileExtensionConfigurationBuilderProvider extends |
| BaseConfigurationBuilderProvider |
| { |
| /** Constant for the file extension separator. */ |
| private static final char EXT_SEPARATOR = '.'; |
| |
| /** The matching configuration class. */ |
| private final String matchingConfigurationClass; |
| |
| /** The file extension. */ |
| private final String extension; |
| |
| /** |
| * Creates a new instance of |
| * {@code FileExtensionConfigurationBuilderProvider}. |
| * |
| * @param bldrCls the name of the builder class |
| * @param reloadBldrCls the name of a builder class to be used if reloading |
| * support is required (<b>null</b> if reloading is not supported) |
| * @param matchingConfigCls the name of the configuration class to be used |
| * if the provided file extension matches (must not be <b>null</b>) |
| * @param defConfigClass the name of the configuration class to be used if |
| * the provided file extension does not match (must not be |
| * <b>null</b>) |
| * @param ext the file extension to select the configuration class (must not |
| * be <b>null</b>) |
| * @param paramCls a collection with the names of parameters classes; an |
| * instance of a parameters object with basic properties is created |
| * automatically and does not need to be contained in this list; the |
| * collection can be <b>null</b> if no additional parameter objects |
| * are needed |
| * @throws IllegalArgumentException if a required parameter is missing |
| */ |
| public FileExtensionConfigurationBuilderProvider(final String bldrCls, |
| final String reloadBldrCls, final String matchingConfigCls, |
| final String defConfigClass, final String ext, final Collection<String> paramCls) |
| { |
| super(bldrCls, reloadBldrCls, defConfigClass, paramCls); |
| if (matchingConfigCls == null) |
| { |
| throw new IllegalArgumentException( |
| "Matching configuration class must not be null!"); |
| } |
| if (ext == null) |
| { |
| throw new IllegalArgumentException( |
| "File extension must not be null!"); |
| } |
| |
| matchingConfigurationClass = matchingConfigCls; |
| extension = ext; |
| } |
| |
| /** |
| * Returns the name of the matching configuration class. This class is used |
| * if the file extension matches the extension of this provider. |
| * |
| * @return the matching configuration class |
| */ |
| public String getMatchingConfigurationClass() |
| { |
| return matchingConfigurationClass; |
| } |
| |
| /** |
| * Returns the file extension of this provider. |
| * |
| * @return the file extension to match |
| */ |
| public String getExtension() |
| { |
| return extension; |
| } |
| |
| /** |
| * {@inheritDoc} This implementation tries to find a |
| * {@link FileBasedBuilderParametersImpl} object in the parameter objects. If |
| * one is found, the extension of the file name is obtained and compared |
| * against the stored file extension. In case of a match, the matching |
| * configuration class is selected, otherwise the default one. |
| */ |
| @Override |
| protected String determineConfigurationClass(final ConfigurationDeclaration decl, |
| final Collection<BuilderParameters> params) throws ConfigurationException |
| { |
| final String currentExt = extractExtension(fetchCurrentFileName(params)); |
| return getExtension().equalsIgnoreCase(currentExt) ? getMatchingConfigurationClass() |
| : getConfigurationClass(); |
| } |
| |
| /** |
| * Tries to obtain the current file name from the given list of parameter |
| * objects. |
| * |
| * @param params the parameter objects |
| * @return the file name or <b>null</b> if unspecified |
| */ |
| private static String fetchCurrentFileName( |
| final Collection<BuilderParameters> params) |
| { |
| for (final BuilderParameters p : params) |
| { |
| if (p instanceof FileBasedBuilderParametersImpl) |
| { |
| final FileBasedBuilderParametersImpl fp = (FileBasedBuilderParametersImpl) p; |
| return fp.getFileHandler().getFileName(); |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Extracts the extension from the given file name. The name can be |
| * <b>null</b>. |
| * |
| * @param fileName the file name |
| * @return the extension (<b>null</b> if there is none) |
| */ |
| private static String extractExtension(final String fileName) |
| { |
| if (fileName == null) |
| { |
| return null; |
| } |
| |
| final int pos = fileName.lastIndexOf(EXT_SEPARATOR); |
| return pos < 0 ? null : fileName.substring(pos + 1); |
| } |
| } |