org.apache.solr.handler.component.SearchComponent.java Source code

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Here is the source code for org.apache.solr.handler.component.SearchComponent.java

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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.handler.component;

import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.solr.common.util.NamedList;
import org.apache.solr.core.SolrInfoBean;
import org.apache.solr.metrics.SolrMetricsContext;
import org.apache.solr.search.facet.FacetModule;
import org.apache.solr.util.plugin.NamedListInitializedPlugin;

/**
 * TODO!
 * 
 *
 * @since solr 1.3
 */
public abstract class SearchComponent implements SolrInfoBean, NamedListInitializedPlugin {
    /**
     * The name given to this component in solrconfig.xml file
     */
    private String name = this.getClass().getName();

    protected SolrMetricsContext solrMetricsContext;

    /**
     * Prepare the response.  Guaranteed to be called before any SearchComponent {@link #process(org.apache.solr.handler.component.ResponseBuilder)} method.
     * Called for every incoming request.
     *
     * The place to do initialization that is request dependent.
     * @param rb The {@link org.apache.solr.handler.component.ResponseBuilder}
     * @throws IOException If there is a low-level I/O error.
     */
    public abstract void prepare(ResponseBuilder rb) throws IOException;

    /**
     * Process the request for this component 
     * @param rb The {@link ResponseBuilder}
     * @throws IOException If there is a low-level I/O error.
     */
    public abstract void process(ResponseBuilder rb) throws IOException;

    /**
     * Process for a distributed search.
     * @return the next stage for this component
     */
    public int distributedProcess(ResponseBuilder rb) throws IOException {
        return ResponseBuilder.STAGE_DONE;
    }

    /** Called after another component adds a request */
    public void modifyRequest(ResponseBuilder rb, SearchComponent who, ShardRequest sreq) {
    }

    /** Called after all responses for a single request were received */
    public void handleResponses(ResponseBuilder rb, ShardRequest sreq) {
    }

    /** Called after all responses have been received for this stage.
     * Useful when different requests are sent to each shard.
     */
    public void finishStage(ResponseBuilder rb) {
    }

    /**
     * Sets the name of the SearchComponent. The name of the component is usually
     * the name defined for it in the configuration.
     */
    public void setName(String name) {
        this.name = name;
    }

    //////////////////////// NamedListInitializedPlugin methods //////////////////////
    @Override
    public void init(NamedList args) {
        // By default do nothing
    }

    //////////////////////// SolrInfoBean methods //////////////////////

    @Override
    public String getName() {
        return name;
    }

    @Override
    public abstract String getDescription();

    @Override
    public Category getCategory() {
        return Category.OTHER;
    }

    @Override
    public SolrMetricsContext getSolrMetricsContext() {
        return solrMetricsContext;
    }

    @Override
    public void initializeMetrics(SolrMetricsContext parentContext, String scope) {
        // By default don't register any metrics - but prepare a child context
        this.solrMetricsContext = parentContext.getChildContext(this);
    }

    public static final Map<String, Class<? extends SearchComponent>> standard_components;

    static {
        HashMap<String, Class<? extends SearchComponent>> map = new HashMap<>();
        map.put(HighlightComponent.COMPONENT_NAME, HighlightComponent.class);
        map.put(QueryComponent.COMPONENT_NAME, QueryComponent.class);
        map.put(FacetComponent.COMPONENT_NAME, FacetComponent.class);
        map.put(FacetModule.COMPONENT_NAME, FacetModule.class);
        map.put(MoreLikeThisComponent.COMPONENT_NAME, MoreLikeThisComponent.class);
        map.put(StatsComponent.COMPONENT_NAME, StatsComponent.class);
        map.put(DebugComponent.COMPONENT_NAME, DebugComponent.class);
        map.put(RealTimeGetComponent.COMPONENT_NAME, RealTimeGetComponent.class);
        map.put(ExpandComponent.COMPONENT_NAME, ExpandComponent.class);
        map.put(TermsComponent.COMPONENT_NAME, TermsComponent.class);

        standard_components = Collections.unmodifiableMap(map);
    }

}