/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.xcontent;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.xcontent.XContentParser.Token;
import org.elasticsearch.rest.action.search.RestSearchAction;
import java.io.IOException;
import java.util.Locale;
import java.util.function.Supplier;
/**
* A set of static methods to get {@link Token} from {@link XContentParser}
* while checking for their types and throw {@link ParsingException} if needed.
*/
public final class XContentParserUtils {
private XContentParserUtils() {
}
/**
* Makes sure that current token is of type {@link XContentParser.Token#FIELD_NAME} and the the field name is equal to the provided one
* @throws ParsingException if the token is not of type {@link XContentParser.Token#FIELD_NAME} or is not equal to the given field name
*/
public static void ensureFieldName(XContentParser parser, Token token, String fieldName) throws IOException {
ensureExpectedToken(Token.FIELD_NAME, token, parser::getTokenLocation);
String currentName = parser.currentName();
if (currentName.equals(fieldName) == false) {
String message = "Failed to parse object: expecting field with name [%s] but found [%s]";
throw new ParsingException(parser.getTokenLocation(), String.format(Locale.ROOT, message, fieldName, currentName));
}
}
/**
* @throws ParsingException with a "unknown field found" reason
*/
public static void throwUnknownField(String field, XContentLocation location) {
String message = "Failed to parse object: unknown field [%s] found";
throw new ParsingException(location, String.format(Locale.ROOT, message, field));
}
/**
* @throws ParsingException with a "unknown token found" reason
*/
public static void throwUnknownToken(XContentParser.Token token, XContentLocation location) {
String message = "Failed to parse object: unexpected token [%s] found";
throw new ParsingException(location, String.format(Locale.ROOT, message, token));
}
/**
* Makes sure that provided token is of the expected type
*
* @throws ParsingException if the token is not equal to the expected type
*/
public static void ensureExpectedToken(Token expected, Token actual, Supplier<XContentLocation> location) {
if (actual != expected) {
String message = "Failed to parse object: expecting token of type [%s] but found [%s]";
throw new ParsingException(location.get(), String.format(Locale.ROOT, message, expected, actual));
}
}
/**
* Parse the current token depending on its token type. The following token types will be
* parsed by the corresponding parser methods:
* <ul>
* <li>XContentParser.Token.VALUE_STRING: parser.text()</li>
* <li>XContentParser.Token.VALUE_NUMBER: parser.numberValue()</li>
* <li>XContentParser.Token.VALUE_BOOLEAN: parser.booleanValue()</li>
* <li>XContentParser.Token.VALUE_EMBEDDED_OBJECT: parser.binaryValue()</li>
* </ul>
*
* @throws ParsingException if the token none of the allowed values
*/
public static Object parseStoredFieldsValue(XContentParser parser) throws IOException {
XContentParser.Token token = parser.currentToken();
Object value = null;
if (token == XContentParser.Token.VALUE_STRING) {
//binary values will be parsed back and returned as base64 strings when reading from json and yaml
value = parser.text();
} else if (token == XContentParser.Token.VALUE_NUMBER) {
value = parser.numberValue();
} else if (token == XContentParser.Token.VALUE_BOOLEAN) {
value = parser.booleanValue();
} else if (token == XContentParser.Token.VALUE_EMBEDDED_OBJECT) {
//binary values will be parsed back and returned as BytesArray when reading from cbor and smile
value = new BytesArray(parser.binaryValue());
} else {
throwUnknownToken(token, parser.getTokenLocation());
}
return value;
}
/**
* This method expects that the current token is a {@code XContentParser.Token.FIELD_NAME} and
* that the current field name is the concatenation of a type, delimiter and name (ex: terms#foo
* where "terms" refers to the type of a registered {@link NamedXContentRegistry.Entry}, "#" is
* the delimiter and "foo" the name of the object to parse).
*
* The method splits the field's name to extract the type and name and then parses the object
* using the {@link XContentParser#namedObject(Class, String, Object)} method.
*
* @param parser the current {@link XContentParser}
* @param delimiter the delimiter to use to splits the field's name
* @param objectClass the object class of the object to parse
* @param <T> the type of the object to parse
* @return the parsed object
* @throws IOException if anything went wrong during parsing or if the type or name cannot be derived
* from the field's name
*/
public static <T> T parseTypedKeysObject(XContentParser parser, String delimiter, Class<T> objectClass) throws IOException {
ensureExpectedToken(XContentParser.Token.FIELD_NAME, parser.currentToken(), parser::getTokenLocation);
String currentFieldName = parser.currentName();
if (Strings.hasLength(currentFieldName)) {
int position = currentFieldName.indexOf(delimiter);
if (position > 0) {
String type = currentFieldName.substring(0, position);
String name = currentFieldName.substring(position + 1);
return parser.namedObject(objectClass, type, name);
}
}
throw new ParsingException(parser.getTokenLocation(), "Cannot parse object of class [" + objectClass.getSimpleName()
+ "] without type information. Set [" + RestSearchAction.TYPED_KEYS_PARAM + "] parameter on the request to ensure the"
+ " type information is added to the response output");
}
}