SingleColumnResolver.java

/*
 * Copyright 2014-2015 the original author or authors
 *
 * Licensed 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 com.wplatform.ddal.dbobject.table;

import com.wplatform.ddal.command.dml.Select;
import com.wplatform.ddal.command.expression.Expression;
import com.wplatform.ddal.command.expression.ExpressionColumn;
import com.wplatform.ddal.value.Value;

/**
 * The single column resolver is like a table with exactly one row.
 * It is used to parse a simple one-column check constraint.
 */
public class SingleColumnResolver implements ColumnResolver {

    private final Column column;
    private Value value;

    SingleColumnResolver(Column column) {
        this.column = column;
    }

    @Override
    public String getTableAlias() {
        return null;
    }

    void setValue(Value value) {
        this.value = value;
    }

    @Override
    public Value getValue(Column col) {
        return value;
    }

    @Override
    public Column[] getColumns() {
        return new Column[]{column};
    }

    @Override
    public String getSchemaName() {
        return null;
    }

    @Override
    public TableFilter getTableFilter() {
        return null;
    }

    @Override
    public Select getSelect() {
        return null;
    }

    @Override
    public Column[] getSystemColumns() {
        return null;
    }

    @Override
    public Column getRowIdColumn() {
        return null;
    }

    @Override
    public Expression optimize(ExpressionColumn expressionColumn, Column col) {
        return expressionColumn;
    }

}