org.apache.solr.request.QueryResponseWriter Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.solr.request;
import java.io.Writer;
import java.io.IOException;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.util.plugin.NamedListInitializedPlugin;
/**
* Implementations of QueryResponseWriter are used to format responses to query requests.
*
* Different QueryResponseWriters are registered with the SolrCore.
* One way to register a QueryResponseWriter with the core is through the solrconfig.xml file.
*
* Example solrconfig.xml entry to register a QueryResponseWriter implementation to
* handle all queries with a writer type of "simple":
*
*
* <queryResponseWriter name="simple" class="foo.SimpleResponseWriter" />
*
*
* A single instance of any registered QueryResponseWriter is created
* via the default constructor and is reused for all relevant queries.
*
* @version $Id: QueryResponseWriter.java 741723 2009-02-06 21:05:20Z otis $
*/
public interface QueryResponseWriter extends NamedListInitializedPlugin {
public static String CONTENT_TYPE_XML_UTF8="text/xml; charset=UTF-8";
public static String CONTENT_TYPE_TEXT_UTF8="text/plain; charset=UTF-8";
public static String CONTENT_TYPE_TEXT_ASCII="text/plain; charset=US-ASCII";
/**
* Write a SolrQueryResponse, this method must be thread save.
*
*
* Information about the request (in particular: formating options) may be
* obtained from req but the dominant source of information
* should be rsp.
*
* There are no mandatory actions that write must perform.
* An empty write implementation would fulfill
* all interface obligations.
*
*/
public void write(Writer writer, SolrQueryRequest request, SolrQueryResponse response) throws IOException;
/**
* Return the applicable Content Type for a request, this method
* must be thread safe.
*
*
* QueryResponseWriter's must implement this method to return a valid
* HTTP Content-Type header for the request, that will logically
* correspond with the output produced by the write method.
*
* @return a Content-Type string, which may not be null.
*/
public String getContentType(SolrQueryRequest request, SolrQueryResponse response);
/** init will be called just once, immediately after creation.
* The args are user-level initialization parameters that
* may be specified when declaring a response writer in
* solrconfig.xml
*/
public void init(NamedList args);
}