org.h2.expression.Wildcard Maven / Gradle / Ivy

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/*
 * Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (https://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.expression;

import java.util.ArrayList;
import java.util.HashMap;

import org.h2.api.ErrorCode;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.table.Column;
import org.h2.table.ColumnResolver;
import org.h2.table.TableFilter;
import org.h2.util.StringUtils;
import org.h2.value.TypeInfo;
import org.h2.value.Value;

/**
 * A wildcard expression as in SELECT * FROM TEST.
 * This object is only used temporarily during the parsing phase, and later
 * replaced by column expressions.
 */
public class Wildcard extends Expression {
    private final String schema;
    private final String table;

    private ArrayList exceptColumns;

    public Wildcard(String schema, String table) {
        this.schema = schema;
        this.table = table;
    }

    public ArrayList getExceptColumns() {
        return exceptColumns;
    }

    public void setExceptColumns(ArrayList exceptColumns) {
        this.exceptColumns = exceptColumns;
    }

    /**
     * Returns map of excluded table columns to expression columns and validates
     * that all columns are resolved and not duplicated.
     *
     * @return map of excluded table columns to expression columns
     */
    public HashMap mapExceptColumns() {
        HashMap exceptTableColumns = new HashMap<>();
        for (ExpressionColumn ec : exceptColumns) {
            Column column = ec.getColumn();
            if (column == null) {
                throw ec.getColumnException(ErrorCode.COLUMN_NOT_FOUND_1);
            }
            if (exceptTableColumns.put(column, ec) != null) {
                throw ec.getColumnException(ErrorCode.DUPLICATE_COLUMN_NAME_1);
            }
        }
        return exceptTableColumns;
    }

    @Override
    public Value getValue(Session session) {
        throw DbException.throwInternalError(toString());
    }

    @Override
    public TypeInfo getType() {
        throw DbException.throwInternalError(toString());
    }

    @Override
    public void mapColumns(ColumnResolver resolver, int level, int state) {
        if (exceptColumns != null) {
            for (ExpressionColumn column : exceptColumns) {
                column.mapColumns(resolver, level, state);
            }
        }
    }

    @Override
    public Expression optimize(Session session) {
        throw DbException.get(ErrorCode.SYNTAX_ERROR_1, table);
    }

    @Override
    public void setEvaluatable(TableFilter tableFilter, boolean b) {
        DbException.throwInternalError(toString());
    }

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

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

    @Override
    public StringBuilder getSQL(StringBuilder builder, boolean alwaysQuote) {
        if (table != null) {
            StringUtils.quoteIdentifier(builder, table).append('.');
        }
        builder.append('*');
        if (exceptColumns != null) {
            builder.append(" EXCEPT (");
            writeExpressions(builder, exceptColumns, alwaysQuote);
            builder.append(')');
        }
        return builder;
    }

    @Override
    public void updateAggregate(Session session, int stage) {
        DbException.throwInternalError(toString());
    }

    @Override
    public boolean isEverything(ExpressionVisitor visitor) {
        if (visitor.getType() == ExpressionVisitor.QUERY_COMPARABLE) {
            return true;
        }
        throw DbException.throwInternalError(Integer.toString(visitor.getType()));
    }

    @Override
    public int getCost() {
        throw DbException.throwInternalError(toString());
    }

}