/*
* 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;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.Objects;
/**
* Constructs a query that only match on documents that the field has a value in them.
*/
public class ExistsQueryBuilder extends AbstractQueryBuilder<ExistsQueryBuilder> {
public static final String NAME = "exists";
public static final ParseField FIELD_FIELD = new ParseField("field");
private final String fieldName;
public ExistsQueryBuilder(String fieldName) {
if (Strings.isEmpty(fieldName)) {
throw new IllegalArgumentException("field name is null or empty");
}
this.fieldName = fieldName;
}
/**
* Read from a stream.
*/
public ExistsQueryBuilder(StreamInput in) throws IOException {
super(in);
fieldName = in.readString();
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
out.writeString(fieldName);
}
/**
* @return the field name that has to exist for this query to match
*/
public String fieldName() {
return this.fieldName;
}
@Override
protected void doXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(NAME);
builder.field(FIELD_FIELD.getPreferredName(), fieldName);
printBoostAndQueryName(builder);
builder.endObject();
}
public static ExistsQueryBuilder fromXContent(QueryParseContext parseContext) throws IOException {
XContentParser parser = parseContext.parser();
String fieldPattern = null;
String queryName = null;
float boost = AbstractQueryBuilder.DEFAULT_BOOST;
XContentParser.Token token;
String currentFieldName = null;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token.isValue()) {
if (FIELD_FIELD.match(currentFieldName)) {
fieldPattern = parser.text();
} else if (AbstractQueryBuilder.NAME_FIELD.match(currentFieldName)) {
queryName = parser.text();
} else if (AbstractQueryBuilder.BOOST_FIELD.match(currentFieldName)) {
boost = parser.floatValue();
} else {
throw new ParsingException(parser.getTokenLocation(), "[" + ExistsQueryBuilder.NAME +
"] query does not support [" + currentFieldName + "]");
}
} else {
throw new ParsingException(parser.getTokenLocation(), "[" + ExistsQueryBuilder.NAME +
"] unknown token [" + token + "] after [" + currentFieldName + "]");
}
}
if (fieldPattern == null) {
throw new ParsingException(parser.getTokenLocation(), "[" + ExistsQueryBuilder.NAME + "] must be provided with a [field]");
}
ExistsQueryBuilder builder = new ExistsQueryBuilder(fieldPattern);
builder.queryName(queryName);
builder.boost(boost);
return builder;
}
@Override
protected Query doToQuery(QueryShardContext context) throws IOException {
return newFilter(context, fieldName);
}
public static Query newFilter(QueryShardContext context, String fieldPattern) {
final FieldNamesFieldMapper.FieldNamesFieldType fieldNamesFieldType =
(FieldNamesFieldMapper.FieldNamesFieldType) context.getMapperService().fullName(FieldNamesFieldMapper.NAME);
if (fieldNamesFieldType == null) {
// can only happen when no types exist, so no docs exist either
return Queries.newMatchNoDocsQuery("Missing types in \"" + NAME + "\" query.");
}
final Collection<String> fields;
if (context.getObjectMapper(fieldPattern) != null) {
// the _field_names field also indexes objects, so we don't have to
// do any more work to support exists queries on whole objects
fields = Collections.singleton(fieldPattern);
} else {
fields = context.simpleMatchToIndexNames(fieldPattern);
}
if (fields.size() == 1) {
Query filter = fieldNamesFieldType.termQuery(fields.iterator().next(), context);
return new ConstantScoreQuery(filter);
}
BooleanQuery.Builder boolFilterBuilder = new BooleanQuery.Builder();
for (String field : fields) {
Query filter = fieldNamesFieldType.termQuery(field, context);
boolFilterBuilder.add(filter, BooleanClause.Occur.SHOULD);
}
return new ConstantScoreQuery(boolFilterBuilder.build());
}
@Override
protected int doHashCode() {
return Objects.hash(fieldName);
}
@Override
protected boolean doEquals(ExistsQueryBuilder other) {
return Objects.equals(fieldName, other.fieldName);
}
@Override
public String getWriteableName() {
return NAME;
}
}