ColumnSchema.java
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package org.hsqldb;
import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.RangeGroup.RangeGroupSimple;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.Iterator;
import org.hsqldb.lib.OrderedHashSet;
import org.hsqldb.rights.Grantee;
import org.hsqldb.types.Type;
import org.hsqldb.types.Types;
/**
 * Implementation of SQL table column metadata.<p>
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.7.3
 * @since 1.9.0
 */
public class ColumnSchema extends ColumnBase implements SchemaObject {
    public static final ColumnSchema[] emptyArray = new ColumnSchema[]{};
    //
    private HsqlName                 columnName;
    private boolean                  isPrimaryKey;
    private Expression               defaultExpression;
    private Expression               generatingExpression;
    private Expression               updateExpression;
    private NumberSequence           sequence;
    private OrderedHashSet<HsqlName> references;
    private OrderedHashSet<HsqlName> generatedColumnReferences;
    private Expression               accessor;
    private int                      systemPeriodType;
    ColumnSchema(HsqlName name, Type type) {
        this.columnName = name;
        this.dataType   = type;
    }
    /**
     * Creates a column defined in DDL statement.
     */
    public ColumnSchema(
            HsqlName name,
            Type type,
            boolean isNullable,
            boolean isPrimaryKey,
            Expression defaultExpression) {
        columnName             = name;
        nullability            = isNullable
                                 ? SchemaObject.Nullability.NULLABLE
                                 : SchemaObject.Nullability.NO_NULLS;
        this.dataType          = type;
        this.isPrimaryKey      = isPrimaryKey;
        this.defaultExpression = defaultExpression;
        setReferences();
    }
    public int getType() {
        return columnName.type;
    }
    public HsqlName getName() {
        return columnName;
    }
    public String getNameString() {
        return columnName.name;
    }
    public String getTableNameString() {
        return columnName.parent == null
               ? null
               : columnName.parent.name;
    }
    public HsqlName getSchemaName() {
        return columnName.schema;
    }
    public String getSchemaNameString() {
        return columnName.schema == null
               ? null
               : columnName.schema.name;
    }
    public HsqlName getCatalogName() {
        return columnName.schema == null
               ? null
               : columnName.schema.schema;
    }
    public String getCatalogNameString() {
        return columnName.schema == null
               ? null
               : columnName.schema.schema == null
                 ? null
                 : columnName.schema.schema.name;
    }
    public Grantee getOwner() {
        return columnName.schema == null
               ? null
               : columnName.schema.owner;
    }
    public OrderedHashSet<HsqlName> getReferences() {
        return references;
    }
    public void compile(Session session, SchemaObject table) {
        if (generatingExpression == null) {
            return;
        }
        generatingExpression.resetColumnReferences();
        generatingExpression.resolveCheckOrGenExpression(
            session,
            new RangeGroupSimple(((Table) table).getDefaultRanges(), false),
            false);
        if (!dataType.canBeAssignedFrom(generatingExpression.getDataType())) {
            throw Error.error(ErrorCode.X_42561);
        }
        setReferences();
    }
    public String getSQL() {
        StringBuilder sb = new StringBuilder();
        switch (parameterMode) {
            case SchemaObject.ParameterModes.PARAM_IN :
                sb.append(Tokens.T_IN).append(' ');
                break;
            case SchemaObject.ParameterModes.PARAM_OUT :
                sb.append(Tokens.T_OUT).append(' ');
                break;
            case SchemaObject.ParameterModes.PARAM_INOUT :
                sb.append(Tokens.T_INOUT).append(' ');
                break;
            default :
        }
        if (columnName != null) {
            sb.append(columnName.statementName).append(' ');
        }
        sb.append(dataType.getTypeDefinition());
        return sb.toString();
    }
    public long getChangeTimestamp() {
        return 0;
    }
    public void setType(Type type) {
        this.dataType = type;
        setReferences();
    }
    public void setName(HsqlName name) {
        this.columnName = name;
    }
    void setIdentity(NumberSequence sequence) {
        this.sequence = sequence;
        isIdentity    = sequence != null;
    }
    void setType(ColumnSchema other) {
        nullability = other.nullability;
        dataType    = other.dataType;
    }
    public NumberSequence getIdentitySequence() {
        return sequence;
    }
    /**
     *  Is column nullable.
     *
     * @return boolean
     */
    public boolean isNullable() {
        boolean isNullable = super.isNullable();
        if (isNullable) {
            if (dataType.isDomainType()) {
                return dataType.userTypeModifier.isNullable();
            }
        }
        return isNullable;
    }
    public byte getNullability() {
        return isPrimaryKey
               ? SchemaObject.Nullability.NO_NULLS
               : super.getNullability();
    }
    public boolean isGenerated() {
        return generatingExpression != null;
    }
    public boolean isAutoUpdate() {
        return updateExpression != null;
    }
    public boolean hasDefault() {
        return getDefaultExpression() != null;
    }
    public void setUpdateExpression(Expression updateExpression) {
        this.updateExpression = updateExpression;
    }
    public Expression getUpdateExpression() {
        return updateExpression;
    }
    /**
     * Is column writeable or always generated
     *
     * @return boolean
     */
    public boolean isWriteable() {
        return isWriteable;
    }
    public void setWriteable(boolean value) {
        isWriteable = value;
    }
    public boolean isSearchable() {
        return Types.isSearchable(dataType.typeCode);
    }
    /**
     *  Is this single column primary key of the table.
     *
     * @return boolean
     */
    public boolean isPrimaryKey() {
        return isPrimaryKey;
    }
    /**
     *  Set primary key.
     *
     */
    void setPrimaryKey(boolean value) {
        isPrimaryKey = value;
    }
    /**
     *  Returns default value in the session context.
     */
    public Object getDefaultValue(Session session) {
        return defaultExpression == null
               ? null
               : defaultExpression.getValue(session, dataType);
    }
    /**
     *  Returns generated value in the session context.
     */
    public Object getGeneratedValue(Session session) {
        return generatingExpression == null
               ? null
               : generatingExpression.getValue(session, dataType);
    }
    /**
     *  Returns SQL for default value.
     */
    public String getDefaultSQL() {
        String ddl = defaultExpression == null
                     ? null
                     : defaultExpression.getSQL();
        return ddl;
    }
    /**
     *  Returns default expression for the column.
     */
    Expression getDefaultExpression() {
        if (defaultExpression == null) {
            if (dataType.isDomainType()) {
                return dataType.userTypeModifier.getDefaultClause();
            }
            return null;
        } else {
            return defaultExpression;
        }
    }
    void setDefaultExpression(Expression expr) {
        defaultExpression = expr;
    }
    /**
     *  Returns generated expression for the column.
     */
    public Expression getGeneratingExpression() {
        return generatingExpression;
    }
    void setGeneratingExpression(Expression expr) {
        generatingExpression = expr;
        setWriteable(generatingExpression == null);
    }
    public boolean isSystemPeriod() {
        return systemPeriodType
               != SchemaObject.PeriodSystemColumnType.PERIOD_ROW_NONE;
    }
    /**
     *  Returns system period type of the column.
     */
    public int getSystemPeriodType() {
        return systemPeriodType;
    }
    void setSystemPeriodType(int type) {
        systemPeriodType = type;
        boolean writable =
            type == SchemaObject.PeriodSystemColumnType.PERIOD_ROW_NONE;
        setWriteable(writable);
    }
    public ColumnSchema duplicate() {
        ColumnSchema copy = new ColumnSchema(
            columnName,
            dataType,
            true,
            isPrimaryKey,
            defaultExpression);
        copy.setNullability(this.nullability);
        copy.setGeneratingExpression(generatingExpression);
        copy.setIdentity(sequence);
        copy.setUpdateExpression(updateExpression);
        copy.setSystemPeriodType(systemPeriodType);
        return copy;
    }
    public Expression getAccessor() {
        if (accessor == null) {
            accessor = new ExpressionColumnAccessor(this);
        }
        return accessor;
    }
    public OrderedHashSet<HsqlName> getGeneratedColumnReferences() {
        return generatedColumnReferences;
    }
    private void setReferences() {
        if (references != null) {
            references.clear();
        }
        if (generatedColumnReferences != null) {
            generatedColumnReferences.clear();
        }
        if (dataType.isDomainType() || dataType.isDistinctType()) {
            HsqlName name = dataType.getName();
            if (references == null) {
                references = new OrderedHashSet<>();
            }
            references.add(name);
        }
        if (generatingExpression != null) {
            OrderedHashSet<HsqlName> set = new OrderedHashSet<>();
            generatingExpression.collectObjectNames(set);
            Iterator<HsqlName> it = set.iterator();
            while (it.hasNext()) {
                HsqlName name = it.next();
                if (name.type == SchemaObject.COLUMN
                        || name.type == SchemaObject.TABLE) {
                    if (name.type == SchemaObject.COLUMN) {
                        if (generatedColumnReferences == null) {
                            generatedColumnReferences = new OrderedHashSet<>();
                        }
                        generatedColumnReferences.add(name);
                    }
                } else {
                    if (references == null) {
                        references = new OrderedHashSet<>();
                    }
                    references.add(name);
                }
            }
        }
    }
}