/**
*
* Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
*
* 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 com.speedment.runtime.config.util;
import com.speedment.runtime.config.Project;
import com.speedment.runtime.config.exception.SpeedmentConfigException;
import com.speedment.runtime.config.internal.ProjectImpl;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.UUID;
import static java.util.Objects.requireNonNull;
/**
* Various utility methods for transcoding and decoding documents into JSON.
*
* @author Emil Forslund
* @since 2.3.0
*/
public final class DocumentTranscoder {
/**
* The element name of the root node in the JSON configuration file. Every
* setting should be located in this element.
*/
public static final String ROOT = "config";
/**
* A functional interface describing a method that encodes a map of
* key-value pairs into a JSON String.
*/
@FunctionalInterface
public interface Encoder {
/**
* Encodes the specified map into a JSON string.
*
* @param map the map to encode
* @return the resulting JSON string
*/
String encode(Map<String, Object> map);
}
/**
* A functional interface describing a method that decodes a JSON String
* into a map of key-value pairs.
*/
@FunctionalInterface
public interface Decoder {
/**
* Decodes the specified JSON string into a map.
*
* @param text the JSON string to decode
* @return the resulting java map
*/
Map<String, Object> decode(String text);
}
/**
* Returns a JSON representation of the specified project node.
*
* @param project the project
* @param encoder the encoder to use
* @return the JSON representation
*
* @throws SpeedmentConfigException if the inputed object is not valid
*/
public static String save(Project project, Encoder encoder)
throws SpeedmentConfigException {
if (project == null) {
return "null";
} else {
try {
final Map<String, Object> root = new LinkedHashMap<>();
root.put(ROOT, project.getData());
return encoder.encode(root);
} catch (final IllegalArgumentException ex) {
throw new SpeedmentConfigException(ex);
}
}
}
/**
* Saves the project in a UTF-8 encoded file.
*
* @param project to save
* @param encoder the encoder to use
* @param location for the UTF-8 encoded file
*
* @throws SpeedmentConfigException if the file could not be saved
*/
public static void save(Project project, Path location, Encoder encoder)
throws SpeedmentConfigException {
try {
Files.write(location, save(project, encoder)
.getBytes(StandardCharsets.UTF_8));
} catch (final IOException ex) {
throw new SpeedmentConfigException(
"Could not save json-file to path '" + location + "'.", ex
);
}
}
/**
* Loads a new {@link Project} from the specified JSON string.
*
* @param json the input json
* @param decoder the decoder to use
* @return the parsed project
*
* @throws SpeedmentConfigException if the file couldn't be loaded
*/
public static Project load(String json, Decoder decoder)
throws SpeedmentConfigException {
requireNonNull(json, "No json value specified.");
try {
final Map<String, Object> root = decoder.decode(json);
@SuppressWarnings("unchecked")
final Map<String, Object> data =
(Map<String, Object>) root.get(ROOT);
if (!data.containsKey(Project.APP_ID)) {
data.put(Project.APP_ID, UUID.randomUUID().toString());
}
return new ProjectImpl(data);
} catch (final Exception ex) {
throw new SpeedmentConfigException(ex);
}
}
/**
* Loads a project from a UTF-8 encoded file.
*
* @param location for the UTF-8 encoded file
* @param decoder the decoder to use
* @return that was loaded
*
* @throws SpeedmentConfigException if the file could not be loaded
*/
public static Project load(Path location, Decoder decoder)
throws SpeedmentConfigException {
try {
final byte[] content = Files.readAllBytes(location);
return load(new String(content, StandardCharsets.UTF_8), decoder);
} catch (final IOException ex) {
throw new SpeedmentConfigException(
"Could not load json-file from path '" + location + "'.", ex
);
}
}
/**
* Utility classes should never be instantiated.
*/
private DocumentTranscoder() {
throw new UnsupportedOperationException();
}
}