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/**
 * Copyright (c) 2009-2016, Data Geekery GmbH (http://www.datageekery.com)
 * All rights reserved.
 *
 * 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.
 *
 * Other licenses:
 * -----------------------------------------------------------------------------
 * Commercial licenses for this work are available. These replace the above
 * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
 * database integrations.
 *
 * For more information, please visit: http://www.jooq.org/licenses
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package org.jooq.impl;

import static org.jooq.impl.DSL.falseCondition;
import static org.jooq.impl.DSL.name;
import static org.jooq.impl.DSL.one;
import static org.jooq.impl.DSL.using;

import org.jooq.Configuration;
import org.jooq.Context;
import org.jooq.Field;
import org.jooq.Record;
import org.jooq.Select;
import org.jooq.Table;

/**
 * Essentially, this is the same as ArrayTable, except that it simulates
 * unnested arrays using UNION ALL
 *
 * @author Lukas Eder
 */
final class ArrayTableEmulation extends AbstractTable {

    /**
     * Generated UID
     */
    private static final long       serialVersionUID = 2392515064450536343L;

    private final Object[]          array;
    private final Fields    field;
    private final String            alias;
    private final String            fieldAlias;

    private transient Table table;

    ArrayTableEmulation(Object[] array) {
        this(array, "array_table", null);
    }

    ArrayTableEmulation(Object[] array, String alias) {
        this(array, alias, null);
    }

    ArrayTableEmulation(Object[] array, String alias, String fieldAlias) {
        super(alias);

        this.array = array;
        this.alias = alias;
        this.fieldAlias = fieldAlias == null ? "COLUMN_VALUE" : fieldAlias;
        this.field = new Fields(DSL.field(name(alias, this.fieldAlias), DSL.getDataType(array.getClass().getComponentType())));
    }

    @Override
    public final Class getRecordType() {
        return RecordImpl.class;
    }

    @Override
    public final Table as(String as) {
        return new ArrayTableEmulation(array, as);
    }

    @Override
    public final Table as(String as, String... fieldAliases) {
        if (fieldAliases == null) {
            return new ArrayTableEmulation(array, as);
        }
        else if (fieldAliases.length == 1) {
            return new ArrayTableEmulation(array, as, fieldAliases[0]);
        }

        throw new IllegalArgumentException("Array table simulations can only have a single field alias");
    }

    @Override
    public final boolean declaresTables() {

        // [#1055] Always true, because unnested tables are always aliased.
        // This is particularly important for simulated unnested arrays
        return true;
    }

    @Override
    public final void accept(Context ctx) {
        ctx.visit(table(ctx.configuration()));
    }

    @Override
    final Fields fields0() {
        return field;
    }

    private final Table table(Configuration configuration) {
        if (table == null) {
            Select select = null;

            for (Object element : array) {

                // [#1081] Be sure to get the correct cast type also for null
                Field val = DSL.val(element, field.fields[0].getDataType());
                Select subselect = using(configuration).select(val.as("COLUMN_VALUE")).select();

                if (select == null) {
                    select = subselect;
                }
                else {
                    select = select.unionAll(subselect);
                }
            }

            // Empty arrays should result in empty tables
            if (select == null) {
                select = using(configuration).select(one().as("COLUMN_VALUE")).select().where(falseCondition());
            }

            table = select.asTable(alias);
        }

        return table;
    }
}