/*
 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.redhat.lightblue.util.Path;

/**
 * Represents a field comparison query of the form
 * <pre>
 * field_comparison_expression := { field: <field>,
 *                                 op: binary_comparison_operator,
 *                                 rfield: <field> }
 * </pre>
 */
public class FieldComparisonExpression extends BinaryRelationalExpression {

    private static final long serialVersionUID = 1L;

    private final Path field;
    private final BinaryComparisonOperator op;
    private final Path rfield;

    /**
     * Ctor with the given values
     */
    public FieldComparisonExpression(Path field,
                                     BinaryComparisonOperator op,
                                     Path rfield) {
        this.field = field;
        this.op = op;
        this.rfield = rfield;
    }

    /**
     * The field on the left side of the operator
     */
    public Path getField() {
        return this.field;
    }

    /**
     * The comparison operator
     */
    public BinaryComparisonOperator getOp() {
        return this.op;
    }

    /**
     * The field on the right side of the operator
     */
    public Path getRfield() {
        return this.rfield;
    }

    /**
     * Returns json representation of the query
     */
    @Override
    public JsonNode toJson() {
        return getFactory().objectNode().put("field", field.toString()).
                put("op", op.toString()).
                put("rfield", rfield.toString());
    }
}