ExpressionColumnAccessor.java

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package org.hsqldb;

import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.lib.List;
import org.hsqldb.lib.OrderedHashSet;
import org.hsqldb.lib.Set;
import org.hsqldb.types.Type;

/**
 * Implementation of column used as assignment target.
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.7.3
 * @since 2.0.0
 */
public class ExpressionColumnAccessor extends Expression {

    ColumnSchema column;

    ExpressionColumnAccessor(ColumnSchema column) {

        super(OpTypes.COLUMN);

        this.column   = column;
        this.dataType = column.getDataType();
    }

    String getAlias() {
        return column.getNameString();
    }

    void collectObjectNames(Set<HsqlName> set) {

        set.add(column.getName());

        if (column.getName().parent != null) {
            set.add(column.getName().parent);
        }
    }

    String getColumnName() {
        return column.getNameString();
    }

    public ColumnSchema getColumn() {
        return column;
    }

    RangeVariable getRangeVariable() {
        return null;
    }

    public List<Expression> resolveColumnReferences(
            Session session,
            RangeGroup rangeGroup,
            int rangeCount,
            RangeGroup[] rangeGroups,
            List<Expression> unresolvedSet,
            boolean acceptsSequences) {
        return unresolvedSet;
    }

    public void resolveTypes(Session session, Expression parent) {}

    public Object getValue(Session session) {
        return null;
    }

    public String getSQL() {
        return column.getName().statementName;
    }

    protected String describe(Session session, int blanks) {
        return column.getName().name;
    }

    public OrderedHashSet<Expression> getUnkeyedColumns(
            OrderedHashSet<Expression> unresolvedSet) {
        return unresolvedSet;
    }

    /**
     * collects all range variables in expression tree
     */
    OrderedHashSet<RangeVariable> collectRangeVariables(
            RangeVariable[] rangeVariables,
            OrderedHashSet<RangeVariable> set) {
        return set;
    }

    Expression replaceAliasInOrderBy(
            Session session,
            List<Expression> columns,
            int length) {
        return this;
    }

    Expression replaceColumnReferences(
            Session session,
            RangeVariable range,
            Expression[] list) {
        return this;
    }

    /**
     * return true if given RangeVariable is used in expression tree
     */
    boolean hasReference(RangeVariable range) {
        return false;
    }

    /**
     * SIMPLE_COLUMN expressions can be of different Expression subclass types
     */
    boolean equals(Expression other) {

        if (other == this) {
            return true;
        }

        if (other == null) {
            return false;
        }

        if (opType != other.opType) {
            return false;
        }

        return column == other.getColumn();
    }

    void replaceRangeVariables(
            RangeVariable[] ranges,
            RangeVariable[] newRanges) {}

    void resetColumnReferences() {}

    public boolean isIndexable(RangeVariable range) {
        return false;
    }

    public boolean isUnresolvedParam() {
        return false;
    }

    boolean isDynamicParam() {
        return false;
    }

    public Type getDataType() {
        return column.getDataType();
    }
}