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 *
 * Redistributions of source code must retain the above copyright notice, this
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 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
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 *
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 * contributors may be used to endorse or promote products derived from this
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package org.hsqldb;

import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.OrderedHashSet;
import org.hsqldb.result.Result;

/**
 * Implementation of Statement for simple PSM signal statements.
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.3
 * @since 1.9.0
 */
public class StatementSignal extends Statement {

    String     sqlState;
    Expression messageExpression;

    StatementSignal(int type, String sqlState, Expression message) {

        super(type, StatementTypes.X_SQL_CONTROL);

        references             = new OrderedHashSet();
        isTransactionStatement = false;
        this.sqlState          = sqlState;
        this.messageExpression = message;
    }

    public String getSQL() {

        StringBuilder sb = new StringBuilder();

        switch (type) {

            case StatementTypes.SIGNAL :
                sb.append(Tokens.T_SIGNAL).append(' ');
                sb.append(Tokens.T_SQLSTATE);
                sb.append(' ').append('\'').append(sqlState).append('\'');
                break;

            case StatementTypes.RESIGNAL :
                sb.append(Tokens.T_RESIGNAL).append(' ');
                sb.append(Tokens.T_SQLSTATE);
                sb.append(' ').append('\'').append(sqlState).append('\'');
                break;
        }

        return sb.toString();
    }

    protected String describe(Session session, int blanks) {

        StringBuilder sb = new StringBuilder();

        sb.append('\n');

        for (int i = 0; i < blanks; i++) {
            sb.append(' ');
        }

        sb.append(Tokens.T_STATEMENT);

        return sb.toString();
    }

    public Result execute(Session session) {

        Result result;

        try {
            result = getResult(session);
        } catch (Throwable t) {
            result = Result.newErrorResult(t);
        }

        if (result.isError()) {
            result.getException().setStatementType(group, type);
        }

        return result;
    }

    Result getResult(Session session) {

        switch (type) {

            /** @todo - check sqlState against allowed values */
            case StatementTypes.SIGNAL :
            case StatementTypes.RESIGNAL :
                HsqlException ex = Error.error(getMessage(session), sqlState);

                return Result.newErrorResult(ex);

            default :
                throw Error.runtimeError(ErrorCode.U_S0500, "StatementSignal");
        }
    }

    void setMessage(Expression message) {
        messageExpression = message;
    }

    String getMessage(Session session) {

        if (messageExpression == null) {
            return null;
        }

        return (String) messageExpression.getValue(session);
    }

    public void resolve(Session session) {

        boolean resolved = false;

        switch (type) {

            case StatementTypes.SIGNAL :
            case StatementTypes.RESIGNAL :
                resolved = true;
                break;

            default :
                throw Error.runtimeError(ErrorCode.U_S0500, "StatementSignal");
        }

        if (!resolved) {
            throw Error.error(ErrorCode.X_42602);
        }
    }

    public String describe(Session session) {
        return "";
    }

    public boolean isCatalogLock(int model) {
        return false;
    }

    public boolean isCatalogChange() {
        return false;
    }
}
