org.apache.solr.search.SortSpec.java Source code

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Here is the source code for org.apache.solr.search.SortSpec.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.search;

import org.apache.lucene.search.Sort;
import org.apache.lucene.search.SortField;
import org.apache.solr.schema.SchemaField;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

/***
 * SortSpec encapsulates a Lucene Sort and a count of the number of documents
 * to return.
 */
public class SortSpec {
    private Sort sort;
    private List<SchemaField> fields;
    private int num = 10;
    private int offset = 0;

    public SortSpec(Sort sort, List<SchemaField> fields, int num, int offset) {
        setSortAndFields(sort, fields);
        this.num = num;
        this.offset = offset;
    }

    public SortSpec(Sort sort, List<SchemaField> fields) {
        setSortAndFields(sort, fields);
    }

    public SortSpec(Sort sort, SchemaField[] fields, int num, int offset) {
        setSortAndFields(sort, Arrays.asList(fields));
        this.num = num;
        this.offset = offset;
    }

    public SortSpec(Sort sort, SchemaField[] fields) {
        setSortAndFields(sort, Arrays.asList(fields));
    }

    /** 
     * the specified SchemaFields must correspond one to one with the Sort's SortFields, 
     * using null where appropriate.
     */
    public void setSortAndFields(Sort s, List<SchemaField> fields) {

        assert null == s
                || s.getSort().length == fields.size() : "SortFields and SchemaFields do not have equal lengths";
        this.sort = s;
        this.fields = Collections.unmodifiableList(fields);
    }

    public static boolean includesScore(Sort sort) {
        if (sort == null)
            return true;
        for (SortField sf : sort.getSort()) {
            if (sf.getType() == SortField.Type.SCORE)
                return true;
        }
        return false;
    }

    public boolean includesScore() {
        return includesScore(sort);
    }

    /**
     * Gets the Lucene Sort object, or null for the default sort
     * by score descending.
     */
    public Sort getSort() {
        return sort;
    }

    /**
     * Gets the Solr SchemaFields that correspond to each of the SortFields used
     * in this sort.  The array may contain null if a SortField doesn't correspond directly 
     * to a SchemaField (ie: score, lucene docid, custom function sorting, etc...)
     *
     * @return an immutable list, may be empty if getSort is null
     */
    public List<SchemaField> getSchemaFields() {
        return fields;
    }

    /**
     * Offset into the list of results.
     */
    public int getOffset() {
        return offset;
    }

    public void setOffset(int offset) {
        this.offset = offset;
    }

    /**
     * Gets the number of documents to return after sorting.
     *
     * @return number of docs to return, or -1 for no cut off (just sort)
     */
    public int getCount() {
        return num;
    }

    public void setCount(int count) {
        this.num = count;
    }

    @Override
    public String toString() {
        return "start=" + offset + "&rows=" + num + (sort == null ? "" : "&sort=" + sort);
    }
}