/**
* 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 org.apache.solr.common.util.NamedList;
import org.apache.solr.common.SolrDocumentList;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrInputDocument;
import org.apache.solr.common.params.CommonParams;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.search.DocList;
import org.apache.solr.search.SolrIndexSearcher;
import org.apache.solr.search.DocIterator;
import org.apache.solr.schema.FieldType;
import org.apache.solr.schema.IndexSchema;
import org.apache.solr.schema.SchemaField;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Fieldable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.List;
import java.util.Set;
import java.util.ArrayList;
/**
*
*
* This class serves as a basis from which {@link QueryResponseWriter}s can be
* developed. The class provides a single method
* {@link #write(SingleResponseWriter, SolrQueryRequest, SolrQueryResponse)}
* that allows users to implement a {@link SingleResponseWriter} sub-class which
* defines how to output {@link SolrInputDocument}s or a
* {@link SolrDocumentList}.
*
* @version $Id: BaseResponseWriter.java 930161 2010-04-02 04:36:13Z rmuir $
* @since 1.5
*
*/
public abstract class BaseResponseWriter {
private static final Logger LOG = LoggerFactory
.getLogger(BaseResponseWriter.class);
private static final String SCORE_FIELD = "score";
/**
*
* The main method that allows users to write {@link SingleResponseWriter}s
* and provide them as the initial parameter <code>responseWriter</code> to
* this method which defines how output should be generated.
*
* @param responseWriter
* The user-provided {@link SingleResponseWriter} implementation.
* @param request
* The provided {@link SolrQueryRequest}.
* @param response
* The provided {@link SolrQueryResponse}.
* @throws IOException
* If any error occurs.
*/
public void write(SingleResponseWriter responseWriter,
SolrQueryRequest request, SolrQueryResponse response) throws IOException {
responseWriter.start();
NamedList nl = response.getValues();
for (int i = 0; i < nl.size(); i++) {
String name = nl.getName(i);
Object val = nl.getVal(i);
if ("responseHeader".equals(name)) {
Boolean omitHeader = request.getParams().getBool(CommonParams.OMIT_HEADER);
if (omitHeader == null || !omitHeader) responseWriter.writeResponseHeader((NamedList) val);
} else if (val instanceof SolrDocumentList) {
SolrDocumentList list = (SolrDocumentList) val;
DocListInfo info = new DocListInfo((int)list.getNumFound(), list.size(), (int)list.getStart(), list.getMaxScore());
if (responseWriter.isStreamingDocs()) {
responseWriter.startDocumentList(name,info);
for (SolrDocument solrDocument : list)
responseWriter.writeDoc(solrDocument);
responseWriter.endDocumentList();
} else {
responseWriter.writeAllDocs(info, list);
}
} else if (val instanceof DocList) {
DocList docList = (DocList) val;
int sz = docList.size();
IdxInfo idxInfo = new IdxInfo(request.getSchema(), request
.getSearcher(), response.getReturnFields());
DocListInfo info = new DocListInfo(docList.matches(), docList.size(),docList.offset(),
docList.maxScore());
DocIterator iterator = docList.iterator();
if (responseWriter.isStreamingDocs()) {
responseWriter.startDocumentList(name,info);
for (int j = 0; j < sz; j++) {
SolrDocument sdoc = getDoc(iterator.nextDoc(), idxInfo);
if (idxInfo.includeScore && docList.hasScores()) {
sdoc.addField(SCORE_FIELD, iterator.score());
}
responseWriter.writeDoc(sdoc);
}
} else {
ArrayList<SolrDocument> list = new ArrayList<SolrDocument>(docList
.size());
for (int j = 0; j < sz; j++) {
SolrDocument sdoc = getDoc(iterator.nextDoc(), idxInfo);
if (idxInfo.includeScore && docList.hasScores()) {
sdoc.addField(SCORE_FIELD, iterator.score());
}
list.add(sdoc);
}
responseWriter.writeAllDocs(info, list);
}
} else {
responseWriter.writeOther(name, val);
}
}
responseWriter.end();
}
/**No ops implementation so that the implementing classes do not have to do it
*/
public void init(NamedList args){}
private static class IdxInfo {
IndexSchema schema;
SolrIndexSearcher searcher;
Set<String> returnFields;
boolean includeScore;
private IdxInfo(IndexSchema schema, SolrIndexSearcher searcher,
Set<String> returnFields) {
this.schema = schema;
this.searcher = searcher;
this.includeScore = returnFields != null
&& returnFields.contains(SCORE_FIELD);
if (returnFields != null) {
if (returnFields.size() == 0 || (returnFields.size() == 1 && includeScore) || returnFields.contains("*")) {
returnFields = null; // null means return all stored fields
}
}
this.returnFields = returnFields;
}
}
private static SolrDocument getDoc(int id, IdxInfo info) throws IOException {
Document doc = info.searcher.doc(id);
SolrDocument solrDoc = new SolrDocument();
for (Fieldable f : (List<Fieldable>) doc.getFields()) {
String fieldName = f.name();
if (info.returnFields != null && !info.returnFields.contains(fieldName))
continue;
SchemaField sf = info.schema.getFieldOrNull(fieldName);
FieldType ft = null;
if (sf != null) ft = sf.getType();
Object val = null;
if (ft == null) { // handle fields not in the schema
if (f.isBinary())
val = f.getBinaryValue();
else
val = f.stringValue();
} else {
try {
if (BinaryResponseWriter.KNOWN_TYPES.contains(ft.getClass())) {
val = ft.toObject(f);
} else {
val = ft.toExternal(f);
}
} catch (Exception e) {
// There is a chance of the underlying field not really matching the
// actual field type . So ,it can throw exception
LOG.warn("Error reading a field from document : " + solrDoc, e);
// if it happens log it and continue
continue;
}
}
if (sf != null && sf.multiValued() && !solrDoc.containsKey(fieldName)) {
ArrayList l = new ArrayList();
l.add(val);
solrDoc.addField(fieldName, l);
} else {
solrDoc.addField(fieldName, val);
}
}
return solrDoc;
}
public static class DocListInfo {
public final int numFound;
public final int start ;
public Float maxScore = null;
public final int size;
public DocListInfo(int numFound, int sz,int start, Float maxScore) {
this.numFound = numFound;
size = sz;
this.start = start;
this.maxScore = maxScore;
}
}
/**
*
* Users wanting to define custom {@link QueryResponseWriter}s that deal with
* {@link SolrInputDocument}s and {@link SolrDocumentList} should override the
* methods for this class. All the methods are w/o body because the user is left
* to choose which all methods are required for his purpose
*/
public static abstract class SingleResponseWriter {
/**
* This method is called at the start of the {@link QueryResponseWriter}
* output. Override this method if you want to provide a header for your
* output, e.g., XML headers, etc.
*
* @throws IOException
* if any error occurs.
*/
public void start() throws IOException { }
/**
* This method is called at the start of processing a
* {@link SolrDocumentList}. Those that override this method are provided
* with {@link DocListInfo} object to use to inspect the output
* {@link SolrDocumentList}.
*
* @param info Information about the {@link SolrDocumentList} to output.
*/
public void startDocumentList(String name, DocListInfo info) throws IOException { }
/**
* This method writes out a {@link SolrDocument}, on a doc-by-doc basis.
* This method is only called when {@link #isStreamingDocs()} returns true.
*
* @param solrDocument
* The doc-by-doc {@link SolrDocument} to transform into output as
* part of this {@link QueryResponseWriter}.
*/
public void writeDoc(SolrDocument solrDocument) throws IOException { }
/**
* This method is called at the end of outputting a {@link SolrDocumentList}
* or on a doc-by-doc {@link SolrDocument} basis.
*/
public void endDocumentList() throws IOException { }
/**
* This method defines how to output the {@link SolrQueryResponse} header
* which is provided as a {@link NamedList} parameter.
*
* @param responseHeader
* The response header to output.
*/
public void writeResponseHeader(NamedList responseHeader) throws IOException { }
/**
* This method is called at the end of the {@link QueryResponseWriter}
* lifecycle. Implement this method to add a footer to your output, e.g., in
* the case of XML, the outer tag for your tag set, etc.
*
* @throws IOException
* If any error occurs.
*/
public void end() throws IOException { }
/**
* Define this method to control how output is written by this
* {@link QueryResponseWriter} if the output is not a
* {@link SolrInputDocument} or a {@link SolrDocumentList}.
*
* @param name
* The name of the object to output.
* @param other
* The object to output.
* @throws IOException
* If any error occurs.
*/
public void writeOther(String name, Object other) throws IOException { }
/**
* Overriding this method to return false forces all
* {@link SolrInputDocument}s to be spit out as a {@link SolrDocumentList}
* so they can be processed as a whole, rather than on a doc-by-doc basis.
* If set to false, this method calls
* {@link #writeAllDocs(DocListInfo, List)}, else if set to true, then this
* method forces calling {@link #writeDoc(SolrDocument)} on a doc-by-doc
* basis. one
*
* @return True to force {@link #writeDoc(SolrDocument)} to be called, False
* to force {@link #writeAllDocs(DocListInfo, List)} to be called.
*/
public boolean isStreamingDocs() { return true; }
/**
* Writes out all {@link SolrInputDocument}s . This is invoked only if
* {@link #isStreamingDocs()} returns false.
*
* @param info
* Information about the {@link List} of {@link SolrDocument}s to
* output.
* @param allDocs
* A {@link List} of {@link SolrDocument}s to output.
* @throws IOException
* If any error occurs.
*/
public void writeAllDocs(DocListInfo info, List<SolrDocument> allDocs) throws IOException { }
}
}