com.redhat.lightblue.query.ArrayMatchExpression.java Source code

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Here is the source code for com.redhat.lightblue.query.ArrayMatchExpression.java

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/*
 Copyright 2013 Red Hat, Inc. and/or its affiliates.
    
 This file is part of lightblue.
    
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
    
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
    
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.redhat.lightblue.query;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.redhat.lightblue.util.Error;
import com.redhat.lightblue.util.Path;

/**
 * Represents a query of the form
 * <pre>
 * array_match_expression := {array: <field>,
 *                            elemMatch: query_expression }
 * </pre>
 */
public class ArrayMatchExpression extends ArrayComparisonExpression {
    private static final long serialVersionUID = 1L;

    private final Path array;
    private final QueryExpression elemMatch;

    /**
     * Ctor with the given values
     */
    public ArrayMatchExpression(Path array, QueryExpression elemMatch) {
        this.array = array;
        this.elemMatch = elemMatch;
    }

    /**
     * The array field. If this is a nested query, relative to the context
     */
    public Path getArray() {
        return this.array;
    }

    /**
     * The nested query that will be matched against array elements
     */
    public QueryExpression getElemMatch() {
        return this.elemMatch;
    }

    /**
     * Returns JSON representation of this query
     */
    @Override
    public JsonNode toJson() {
        return getFactory().objectNode().put("array", array.toString()).set("elemMatch", elemMatch.toJson());
    }

    /**
     * Parses an array match expression from the given json object
     */
    public static ArrayMatchExpression fromJson(ObjectNode node) {
        JsonNode x = node.get("array");
        if (x != null) {
            Path field = new Path(x.asText());
            x = node.get("elemMatch");
            if (x != null) {
                return new ArrayMatchExpression(field, QueryExpression.fromJson(x));
            }
        }
        throw Error.get(QueryConstants.ERR_INVALID_ARRAY_COMPARISON_EXPRESSION, node.toString());
    }
}