/*
* 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.update.processor;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.response.SolrQueryResponse;
import org.apache.solr.util.plugin.PluginInfoInitialized;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.common.SolrException;
import org.apache.solr.core.PluginInfo;
import org.apache.solr.core.SolrCore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
import java.util.ArrayList;
/**
* Manages a chain of UpdateRequestProcessorFactories.
* <p>
* Chains can be configured via solrconfig.xml using the following syntax...
* </p>
* <pre class="prettyprint">
* <updateRequestProcessorChain name="key" default="true">
* <processor class="package.Class1" />
* <processor class="package.Class2" >
* <str name="someInitParam1">value</str>
* <int name="someInitParam2">42</int>
* </processor>
* <processor class="solr.LogUpdateProcessorFactory" >
* <int name="maxNumToLog">100</int>
* </processor>
* <processor class="solr.RunUpdateProcessorFactory" />
* </updateRequestProcessorChain>
* </pre>
* <p>
* Multiple Chains can be defined, each with a distinct name. The name of
* a chain used to handle an update request may be specified using the request
* param <code>update.chain</code>. If no chain is explicitly selected
* by name, then Solr will attempt to determine a default chain:
* </p>
* <ul>
* <li>A single configured chain may explicitly be declared with
* <code>default="true"</code> (see example above)</li>
* <li>If no chain is explicitly declared as the default, Solr will look for
* any chain that does not have a name, and treat it as the default</li>
* <li>As a last resort, Solr will create an implicit default chain
* consisting of:<ul>
* <li>{@link LogUpdateProcessorFactory}</li>
* <li>{@link DistributedUpdateProcessorFactory}</li>
* <li>{@link RunUpdateProcessorFactory}</li>
* </ul></li>
* </ul>
*
* <p>
* Allmost all processor chains should end with an instance of
* <code>RunUpdateProcessorFactory</code> unless the user is explicitly
* executing the update commands in an alternative custom
* <code>UpdateRequestProcessorFactory</code>. If a chain includes
* <code>RunUpdateProcessorFactory</code> but does not include a
* <code>DistributingUpdateProcessorFactory</code>, it will be added
* automatically by {@link #init init()}.
* </p>
*
* @see UpdateRequestProcessorFactory
* @see #init
* @see #createProcessor
* @since solr 1.3
*/
public final class UpdateRequestProcessorChain implements PluginInfoInitialized
{
public final static Logger log = LoggerFactory.getLogger(UpdateRequestProcessorChain.class);
private UpdateRequestProcessorFactory[] chain;
private final SolrCore solrCore;
public UpdateRequestProcessorChain(SolrCore solrCore) {
this.solrCore = solrCore;
}
/**
* Initializes the chain using the factories specified by the <code>PluginInfo</code>.
* if the chain includes the <code>RunUpdateProcessorFactory</code>, but
* does not include an implementation of the
* <code>DistributingUpdateProcessorFactory</code> interface, then an
* instance of <code>DistributedUpdateProcessorFactory</code> will be
* injected immediately prior to the <code>RunUpdateProcessorFactory</code>.
*
* @see DistributingUpdateProcessorFactory
* @see RunUpdateProcessorFactory
* @see DistributedUpdateProcessorFactory
*/
@Override
public void init(PluginInfo info) {
final String infomsg = "updateRequestProcessorChain \"" +
(null != info.name ? info.name : "") + "\"" +
(info.isDefault() ? " (default)" : "");
log.info("creating " + infomsg);
// wrap in an ArrayList so we know we know we can do fast index lookups
// and that add(int,Object) is supported
List<UpdateRequestProcessorFactory> list = new ArrayList
(solrCore.initPlugins(info.getChildren("processor"),UpdateRequestProcessorFactory.class,null));
if(list.isEmpty()){
throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
infomsg + " require at least one processor");
}
int numDistrib = 0;
int runIndex = -1;
// hi->lo incase multiple run instances, add before first one
// (no idea why someone might use multiple run instances, but just in case)
for (int i = list.size()-1; 0 <= i; i--) {
UpdateRequestProcessorFactory factory = list.get(i);
if (factory instanceof DistributingUpdateProcessorFactory) {
numDistrib++;
}
if (factory instanceof RunUpdateProcessorFactory) {
runIndex = i;
}
}
if (1 < numDistrib) {
throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
infomsg + " may not contain more then one " +
"instance of DistributingUpdateProcessorFactory");
}
if (0 <= runIndex && 0 == numDistrib) {
// by default, add distrib processor immediately before run
DistributedUpdateProcessorFactory distrib
= new DistributedUpdateProcessorFactory();
distrib.init(new NamedList());
list.add(runIndex, distrib);
log.info("inserting DistributedUpdateProcessorFactory into " + infomsg);
}
chain = list.toArray(new UpdateRequestProcessorFactory[list.size()]);
}
/**
* Creates a chain backed directly by the specified array. Modifications to
* the array will affect future calls to <code>createProcessor</code>
*/
public UpdateRequestProcessorChain( UpdateRequestProcessorFactory[] chain,
SolrCore solrCore) {
this.chain = chain;
this.solrCore = solrCore;
}
/**
* Uses the factories in this chain to creates a new
* <code>UpdateRequestProcessor</code> instance specific for this request.
* If the <code>DISTRIB_UPDATE_PARAM</code> is present in the request and is
* non-blank, then any factory in this chain prior to the instance of
* <code>{@link DistributingUpdateProcessorFactory}</code> will be skipped,
* except for the log update processor factory.
*
* @see UpdateRequestProcessorFactory#getInstance
* @see DistributingUpdateProcessorFactory#DISTRIB_UPDATE_PARAM
*/
public UpdateRequestProcessor createProcessor(SolrQueryRequest req,
SolrQueryResponse rsp)
{
UpdateRequestProcessor processor = null;
UpdateRequestProcessor last = null;
final String distribPhase = req.getParams().get(DistributingUpdateProcessorFactory.DISTRIB_UPDATE_PARAM);
final boolean skipToDistrib = distribPhase != null;
boolean afterDistrib = true; // we iterate backwards, so true to start
for (int i = chain.length-1; i>=0; i--) {
UpdateRequestProcessorFactory factory = chain[i];
if (skipToDistrib) {
if (afterDistrib) {
if (factory instanceof DistributingUpdateProcessorFactory) {
afterDistrib = false;
}
} else if (!(factory instanceof UpdateRequestProcessorFactory.RunAlways)) {
// skip anything that doesn't have the marker interface
continue;
}
}
processor = factory.getInstance(req, rsp, last);
last = processor == null ? last : processor;
}
return last;
}
/**
* Returns the underlying array of factories used in this chain.
* Modifications to the array will affect future calls to
* <code>createProcessor</code>
*/
public UpdateRequestProcessorFactory[] getFactories() {
return chain;
}
}