com.redhat.lightblue.query.FieldBinding Maven / Gradle / Ivy

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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 .
 */
package com.redhat.lightblue.query;

import com.redhat.lightblue.util.Path;

import java.io.Serializable;

/**
 * Base class for a bound value. The bound value cam be a primitive
 * (BoundValue) or a list (BoundValueList). When a field is bound to a
 * value, that query clause is replaced with another one containing a
 * BoundValue or BoundValueList. The FieldBinding for this instance
 * keeps the field path, the value it is bound to, the original query
 * expression (originalQuery), and the new query expression containing
 * the bound value (boundQuery). For instance, consider the following
 * expression: 
 *
 *  
 *  { "field":"field1","op":"=","rfield":"field2" }
 *  
 *
 * When field1 is bound to a value, the FieldBinding is:
 *  field: field1 originalQuery: {
 * "field":"field1","op":"=","rfield":"field2" } boundQuery:
 * {"field":"field2","op":"=","rvalue": } value:  
 */
public abstract class FieldBinding implements Serializable {
    private static final long serialVersionUID = 1L;

    private final Path field;
    private final QueryExpression originalQuery;
    private final QueryExpression boundQuery;

    public FieldBinding(Path field,
                        QueryExpression originalQ,
                        QueryExpression boundQ) {
        this.field = field;
        this.originalQuery = originalQ;
        this.boundQuery = boundQ;
    }

    /**
     * Returns the field bound to a value.
     */
    public Path getField() {
        return field;
    }

    /**
     * Returns the original query object
     */
    public QueryExpression getOriginalQuery() {
        return originalQuery;
    }

    /**
     * Returns the rewritten query object containing the bound value
     */
    public QueryExpression getBoundQuery() {
        return boundQuery;
    }
}