org.apache.solr.response.QueryResponseWriterUtil.java Source code

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/*
 * 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.response;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.charset.StandardCharsets;

import org.apache.solr.common.util.ContentStreamBase;
import org.apache.solr.common.util.FastWriter;
import org.apache.solr.request.SolrQueryRequest;

/**
 * Static utility methods relating to {@link QueryResponseWriter}s
 */
public final class QueryResponseWriterUtil {
    private QueryResponseWriterUtil() {
        /* static helpers only */ }

    /**
     * Writes the response writer's result to the given output stream.
     * This method inspects the specified writer to determine if it is a 
     * {@link BinaryQueryResponseWriter} or not to delegate to the appropriate method.
     * @see BinaryQueryResponseWriter#write(OutputStream,SolrQueryRequest,SolrQueryResponse)
     * @see BinaryQueryResponseWriter#write(Writer,SolrQueryRequest,SolrQueryResponse)
     */
    public static void writeQueryResponse(OutputStream outputStream, QueryResponseWriter responseWriter,
            SolrQueryRequest solrRequest, SolrQueryResponse solrResponse, String contentType) throws IOException {

        if (responseWriter instanceof BinaryQueryResponseWriter) {
            BinaryQueryResponseWriter binWriter = (BinaryQueryResponseWriter) responseWriter;
            binWriter.write(outputStream, solrRequest, solrResponse);
        } else {
            OutputStream out = new OutputStream() {
                @Override
                public void write(int b) throws IOException {
                    outputStream.write(b);
                }

                @Override
                public void flush() throws IOException {
                    // We don't flush here, which allows us to flush below
                    // and only flush internal buffers, not the response.
                    // If we flush the response early, we trigger chunked encoding.
                    // See SOLR-8669.
                }
            };
            Writer writer = buildWriter(out, ContentStreamBase.getCharsetFromContentType(contentType));
            responseWriter.write(writer, solrRequest, solrResponse);
            writer.flush();
        }
    }

    private static Writer buildWriter(OutputStream outputStream, String charset)
            throws UnsupportedEncodingException {
        Writer writer = (charset == null) ? new OutputStreamWriter(outputStream, StandardCharsets.UTF_8)
                : new OutputStreamWriter(outputStream, charset);

        return new FastWriter(writer);
    }
}