net.logstash.logback.composite.JsonReadingUtils Maven / Gradle / Ivy
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/*
* Copyright 2013-2022 the original author or authors.
*
* 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 net.logstash.logback.composite;
import java.io.IOException;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
/**
* Utilities for reading/parsing JSON string.
*
* Note: This class is for internal use only and subject to backward incompatible change
* at any time.
*
* @author brenuart
*/
public class JsonReadingUtils {
private JsonReadingUtils() {
// utility class - prevent instantiation
}
/**
* Fully read the supplied JSON string into the equivalent {@link JsonNode}.
*
* Throws a {@link JsonParseException} if the string is not fully read after a first valid JsonNode is found.
* This may happen for input like 10 foobar that would otherwise return a NumericNode with value
* {@code 10} leaving foobar unread.
*
* @param jsonFactory the {@link JsonFactory} from which to obtain a {@link JsonParser} to read the JSON string.
* @param json the JSON string to read
* @return the {@link JsonNode} corresponding to the input string or {@code null} if the string is null or empty.
* @throws IOException if there is either an underlying I/O problem or decoding issue
*/
public static JsonNode readFully(JsonFactory jsonFactory, String json) throws IOException {
if (json == null) {
return null;
}
final String trimmedJson = json.trim();
try (JsonParser parser = jsonFactory.createParser(trimmedJson)) {
final JsonNode tree = parser.readValueAsTree();
if (parser.getCurrentLocation().getCharOffset() < trimmedJson.length()) {
/*
* If the full trimmed string was not read, then the full trimmed string contains a json value plus other text.
* For example, trimmedValue = '10 foobar', or 'true foobar', or '{"foo","bar"} baz'.
* In these cases readTree will only read the first part, and will not read the remaining text.
*/
throw new JsonParseException(parser, "unexpected character");
}
return tree;
}
}
/**
* Fully read a JSON string into an {@link ObjectNode}, throwing a {@link JsonParseException} if the supplied string
* is not a valid JSON object representation.
*
* @param jsonFactory the {@link JsonFactory} from which to obtain a {@link JsonParser} to read the JSON string.
* @param json the JSON string to read
* @return the {@link JsonNode} corresponding to the input string or {@code null} if the string is null or empty.
* @throws IOException if there is either an underlying I/O problem or decoding issue
*
* @see JsonReadingUtils#readFully(JsonFactory, String)
*/
public static ObjectNode readFullyAsObjectNode(JsonFactory jsonFactory, String json) throws IOException {
final JsonNode node = readFully(jsonFactory, json);
if (node != null && !(node instanceof ObjectNode)) {
throw new JsonParseException(null, "expected a JSON object representation");
}
return (ObjectNode) node; }
}