BsonRegexDeserializer.java

// Copyright 2010-2016 Michel Kraemer
//
// 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 de.undercouch.bson4jackson.deserializers;

import java.io.IOException;
import java.util.regex.Pattern;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.core.TreeNode;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.node.ValueNode;

import de.undercouch.bson4jackson.BsonConstants;
import de.undercouch.bson4jackson.BsonParser;

/**
 * Deserializes BSON Regex objects (Patterns)
 * @author Michel Kraemer
 * @since 2.8.0
 */
public class BsonRegexDeserializer extends JsonDeserializer<Pattern> {
	@Override
	@SuppressWarnings("deprecation")
	public Pattern deserialize(JsonParser jp, DeserializationContext ctxt)
			throws IOException {
		if (jp instanceof BsonParser) {
			BsonParser bsonParser = (BsonParser)jp;
			if (bsonParser.getCurrentToken() != JsonToken.VALUE_EMBEDDED_OBJECT ||
					bsonParser.getCurrentBsonType() != BsonConstants.TYPE_REGEX) {
				throw ctxt.mappingException(Pattern.class);
			}
			return (Pattern)bsonParser.getEmbeddedObject();
		} else {
			TreeNode tree = jp.getCodec().readTree(jp);
			
			String pattern = null;
			TreeNode patternNode = tree.get("$pattern");
			if (patternNode instanceof ValueNode) {
				pattern = ((ValueNode)patternNode).asText();
			}
			
			int flags = 0;
			TreeNode flagsNode = tree.get("$flags");
			if (flagsNode instanceof ValueNode) {
				flags = ((ValueNode)flagsNode).asInt();
			}
			
			return Pattern.compile(pattern, flags);
		}
	}
}