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

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Here is the source code for org.apache.solr.search.ReturnFields.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 java.util.Map;
import java.util.Set;

import org.apache.solr.response.transform.DocTransformer;

/**
 * A class representing the return fields
 *
 *
 * @since solr 4.0
 */
public abstract class ReturnFields {
    /**
     * Set of field names with their exact names from the lucene index.
     * Class such as ResponseWriters pass this to {@link SolrIndexSearcher#doc(int, Set)}.
     * <p>
     * NOTE: In some situations, this method may return <code>null</code> even if {@link #wantsAllFields()} 
     * is <code>false</code>.  For example: When glob expressions are used ({@link #hasPatternMatching}), 
     * it is safer to request all field names then to attempt to resolve the globs against all possible 
     * dynamic field names in the index.
     * </p>
     * @return Set of field names or <code>null</code> (all fields).
     */
    public abstract Set<String> getLuceneFieldNames();

    /**
     * Set of field names with their exact names from the lucene index.
     *
     * @param ignoreWantsAll If true, it returns any additional specified field names, in spite of
     *                       also wanting all fields. Example: when fl=*,field1, returns ["field1"].
     *                       If false, the method returns null when all fields are wanted. Example: when fl=*,field1, returns null.
     *                       Note that this method returns null regardless of ignoreWantsAll if all fields
     *                       are requested and no explicit field names are specified.
     */
    public abstract Set<String> getLuceneFieldNames(boolean ignoreWantsAll);

    /**
     * The requested field names (includes pseudo fields)
     * <p>
     * @return Set of field names or <code>null</code> (all fields).
     */
    public abstract Set<String> getRequestedFieldNames();

    /**
     * The explicitly requested field names (includes pseudo fields)
     * <p>
     * @return Set of explicitly requested field names or <code>null</code> (no explict)
     */
    public abstract Set<String> getExplicitlyRequestedFieldNames();

    /**
     * Get the fields which have been renamed
     * @return a mapping of renamed fields
     */
    public abstract Map<String, String> getFieldRenames();

    /** 
     * Returns <code>true</code> if the specified field should be returned <em>to the external client</em> 
     * -- either using its own name, or via an alias. 
     * This method returns <code>false</code> even if the specified name is needed as an "extra" field
     * for use by transformers.
     */
    public abstract boolean wantsField(String name);

    /** 
     * Returns <code>true</code> if all fields should be returned <em>to the external client</em>. 
     */
    public abstract boolean wantsAllFields();

    /** Returns <code>true</code> if the score should be returned. */
    public abstract boolean wantsScore();

    /** Returns <code>true</code> if the fieldnames should be picked with a pattern */
    public abstract boolean hasPatternMatching();

    /** Returns the DocTransformer used to modify documents, or <code>null</code> */
    public abstract DocTransformer getTransformer();
}