io.confound.config.file.ConfigurationFileFormat Maven / Gradle / Ivy

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Managed configurations for file-based configurations.
There is a newer version: 0.8.0
/*
 * Copyright © 2018 GlobalMentor, Inc. 
 *
 * 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 io.confound.config.file;

import java.io.*;
import java.nio.charset.CharacterCodingException;
import java.util.Set;

import javax.annotation.*;

import io.confound.config.Configuration;

/**
 * A strategy for loading a configuration from an input stream.
 * @author Garret Wilson
 */
public interface ConfigurationFileFormat {

	/**
	 * Retrieves the extension suffixes of files supported by this file format.
	 * 
	 * An extension suffix is merely a file suffix of any type, except that it is understood that the full stop . character
	 * U+002E will be prepended to the suffix. For example, an extension suffix of foo.bar would match a file ending in
	 * .foo.bar, such as example.foo.bar.
	 * 
	 * @return The extension suffixes of filenames for file type supported by this loader.
	 */
	public Set getFilenameExtensionSuffixes();

	/**
	 * Loads a configuration from the given input stream with no parent configuration.
	 * 
	 * The given input stream is guaranteed to support {@link InputStream#mark(int)} and {@link InputStream#reset()}.
	 * 
	 * 
	 * The input stream must not be closed by this method.
	 * 
	 * 
	 * The default implementation delegates to {@link #load(InputStream, Configuration)} and shuld normally not be overridden.
	 * 
	 * @param inputStream The input stream from which the configuration will be loaded.
	 * @return A new configuration, loaded from the given input stream.
	 * @throws IOException if there is an error loading a configuration from the giving input stream.
	 * @throws CharacterCodingException if the given input stream contains an invalid byte sequence for the charset indicated by the BOM; or if no BOM was
	 *           present, an invalid byte sequence for the assumed charset, depending on the file format.
	 * @see InputStream#markSupported()
	 */
	public default @Nonnull Configuration load(@Nonnull final InputStream inputStream) throws IOException {
		return load(inputStream, null);
	}

	/**
	 * Loads a configuration from the given input stream.
	 * 
	 * The given input stream is guaranteed to support {@link InputStream#mark(int)} and {@link InputStream#reset()}.
	 * 
	 * 
	 * The input stream must not be closed by this method.
	 * 
	 * @param inputStream The input stream from which the configuration will be loaded.
	 * @param parentConfiguration The parent configuration to use for fallback lookup, or null if there is no parent configuration.
	 * @return A new configuration, loaded from the given input stream.
	 * @throws IOException if there is an error loading a configuration from the giving input stream.
	 * @throws CharacterCodingException if the given input stream contains an invalid byte sequence for the charset indicated by the BOM; or if no BOM was
	 *           present, an invalid byte sequence for the assumed charset, depending on the file format.
	 * @see InputStream#markSupported()
	 */
	public @Nonnull Configuration load(@Nonnull final InputStream inputStream, @Nullable final Configuration parentConfiguration) throws IOException;

}