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/*
* 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.index.query.support;
import org.apache.lucene.search.Query;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.query.QueryParseContext;
import java.io.IOException;
/**
* XContentStructure is a class used to capture a subset of query, to be parsed
* at a later time when more information (in this case, types) is available.
* Note that using this class requires copying the parser's data, which will
* result in additional overhead versus parsing the inner query/filter
* immediately, however, the extra overhead means that the type not be
* extracted prior to query parsing (in the case of unordered JSON).
*/
public abstract class XContentStructure {
private final QueryParseContext parseContext;
private BytesReference innerBytes;
/**
* Create a new XContentStructure for the current parsing context.
*/
public XContentStructure(QueryParseContext queryParseContext) {
this.parseContext = queryParseContext;
}
/**
* "Freeze" the parsing content, which means copying the current parser's
* structure into an internal {@link BytesReference} to be parsed later.
* @return the original XContentStructure object
*/
public XContentStructure freeze() throws IOException {
this.bytes(XContentFactory.smileBuilder().copyCurrentStructure(parseContext.parser()).bytes());
return this;
}
/**
* Set the bytes to be used for parsing
*/
public void bytes(BytesReference innerBytes) {
this.innerBytes = innerBytes;
}
/**
* Return the bytes that are going to be used for parsing
*/
public BytesReference bytes() {
return this.innerBytes;
}
/**
* Use the captured bytes to parse the inner query using the specified
* types. The original QueryParseContext's parser is switched during this
* parsing, so this method is NOT thread-safe.
* @param types types to be used during the inner query parsing
* @return {@link Query} parsed from the bytes captured in {@code freeze()}
*/
public Query asQuery(String... types) throws IOException {
BytesReference br = this.bytes();
assert br != null : "innerBytes must be set with .bytes(bytes) or .freeze() before parsing";
XContentParser innerParser = XContentHelper.createParser(br);
String[] origTypes = QueryParseContext.setTypesWithPrevious(types);
XContentParser old = parseContext.parser();
parseContext.parser(innerParser);
try {
return parseContext.parseInnerQuery();
} finally {
parseContext.parser(old);
QueryParseContext.setTypes(origTypes);
}
}
/**
* InnerQuery is an extension of {@code XContentStructure} that eagerly
* parses the query in a streaming manner if the types are available at
* construction time.
*/
public static class InnerQuery extends XContentStructure {
private Query query = null;
private boolean queryParsed = false;
public InnerQuery(QueryParseContext parseContext1, @Nullable String... types) throws IOException {
super(parseContext1);
if (types != null) {
String[] origTypes = QueryParseContext.setTypesWithPrevious(types);
try {
query = parseContext1.parseInnerQuery();
queryParsed = true;
} finally {
QueryParseContext.setTypes(origTypes);
}
} else {
BytesReference innerBytes = XContentFactory.smileBuilder().copyCurrentStructure(parseContext1.parser()).bytes();
super.bytes(innerBytes);
}
}
/**
* Return the query represented by the XContentStructure object,
* returning the cached Query if it has already been parsed.
* @param types types to be used during the inner query parsing
*/
@Override
public Query asQuery(String... types) throws IOException {
if (!queryParsed) { // query can be null
this.query = super.asQuery(types);
}
return this.query;
}
}
}