org.elasticsearch.index.fieldvisitor.CustomFieldsVisitor Maven / Gradle / Ivy

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/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.index.fieldvisitor;

import org.apache.lucene.index.FieldInfo;

import java.util.HashSet;
import java.util.Set;

/**
 * A field visitor that allows to load a selection of the stored fields by exact name or by pattern.
 * Supported pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy".
 * The Uid field is always loaded.
 * The class is optimized for source loading as it is a common use case.
 */
public class CustomFieldsVisitor extends FieldsVisitor {

    private final Set fields;

    public CustomFieldsVisitor(Set fields, boolean loadSource) {
        super(loadSource);
        this.fields = fields;
    }

    @Override
    public Set getFieldNames() {
        Set fields = new HashSet<>(super.getFieldNames());
        fields.addAll(this.fields);
        return fields;
    }

    @Override
    public Status needsField(FieldInfo fieldInfo) {
        if (super.needsField(fieldInfo) == Status.YES) {
            return Status.YES;
        }
        if (fields.contains(fieldInfo.name)) {
            return Status.YES;
        }
        return Status.NO;
    }
}