/*
* Copyright (c) 2010 Yahoo! Inc. All rights reserved.
*
* Licensed 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. See accompanying LICENSE file.
*/
package io.s4.message;
import io.s4.dispatcher.partitioner.CompoundKeyInfo;
import io.s4.dispatcher.partitioner.Hasher;
import io.s4.processor.PrototypeWrapper;
import io.s4.util.MethodInvoker;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
/**
* A request for a value from the prototype of PEs.
*/
public class PrototypeRequest extends Request {
private final List<String> query;
public PrototypeRequest(List<String> query, RInfo info) {
this.query = query;
this.rinfo = info;
}
public PrototypeRequest(List<String> query) {
this.query = query;
this.rinfo = null;
}
public PrototypeRequest() {
this.query = Collections.<String> emptyList();
this.rinfo = null;
}
public String toString() {
return "PROTOTYPE: query=[" + query + "] info=[" + rinfo + "]";
}
/**
* List of queries to execute.
*
* @return list of queries
*/
public List<String> getQuery() {
return query;
}
/**
* Evaluate Request on a particular PE Prototype.
*
* @param pe
* prototype
* @return Response object.
*/
public Response evaluate(PrototypeWrapper pw) {
HashMap<String, Object> results = new HashMap<String, Object>();
HashMap<String, String> exceptions = new HashMap<String, String>();
for (String q : query) {
if (q.startsWith("$")) {
// requests for getters should be of the form $fieldA.
// Responds with pe.getFieldA()
try {
Object res = MethodInvoker.invokeGetter(pw, q.substring(1));
results.put(q, res);
} catch (Exception e) {
exceptions.put(q, e.toString());
}
} else if (q.equalsIgnoreCase("count")) {
// Some aggregate operators
results.put(q, pw.getPECount());
} else {
exceptions.put(q, "Query Parse Error");
}
}
return new Response(results, exceptions, this);
}
public List<CompoundKeyInfo> partition(Hasher h, String delim, int partCount) {
// send to all partitions
List<CompoundKeyInfo> partitionInfoList = new ArrayList<CompoundKeyInfo>();
for (int i = 0; i < partCount; ++i) {
CompoundKeyInfo partitionInfo = new CompoundKeyInfo();
partitionInfo.setPartitionId(i);
partitionInfoList.add(partitionInfo);
}
return partitionInfoList;
}
}