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package oracle.toplink.essentials.internal.expressions;

import java.io.*;
import java.util.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.expressions.*;

public class TableExpression extends DataExpression {
    protected DatabaseTable table;

    /**
     * TableExpression constructor comment.
     */
    public TableExpression() {
        super();
    }

    /**
     * TableExpression constructor comment.
     */
    public TableExpression(DatabaseTable aTable) {
        super();
        table = aTable;
    }

    /**
     * INTERNAL:
     * Used for debug printing.
     */
    public String descriptionOfNodeType() {
        return "Table";
    }

    /**
     * INTERNAL:
     * Fully-qualify the databaseField if the table is known.
     * CR 3791
     */
    public Expression getField(String fieldName) {
        // we need to check for full table qualification
        DatabaseField field = new DatabaseField(fieldName);
        if (!field.hasTableName()) {
            field.setTable(getTable());
        }
        return getField(field);
    }

    /**
     * INTERNAL:
     */
    public Vector getOwnedTables() {
        Vector result = new Vector(1);
        result.addElement(getTable());
        return result;
    }

    public DatabaseTable getTable() {
        return table;
    }

    public boolean isTableExpression() {
        return true;
    }

    /**
     * INTERNAL:
     * Normalize the expression into a printable structure.
     * Any joins must be added to form a new root.
     */
    public Expression normalize(ExpressionNormalizer normalizer) {
		//Bug4736461  Only setTableQualifier if getDatasourceLogin().getTableQualifier() is an empty string to make the window much smaller when
		//DatabaseTable.qualifiedName is reset
        if (getTable().getTableQualifier().length() == 0 && (normalizer.getSession().getDatasourceLogin().getTableQualifier().length() != 0)) {
            getTable().setTableQualifier(normalizer.getSession().getDatasourceLogin().getTableQualifier());
        }
        return super.normalize(normalizer);
    }

    /**
     * INTERNAL:
     * This expression is built on a different base than the one we want. Rebuild it and
     * return the root of the new tree
     */
    public Expression rebuildOn(Expression newBase) {
        Expression newLocalBase = getBaseExpression().rebuildOn(newBase);
        return newLocalBase.getTable(getTable());

    }

    /**
     * INTERNAL:
     * Added for temporal querying.
     */
    public void setTable(DatabaseTable table) {
        this.table = table;
    }

    /**
     * INTERNAL:
     * Rebuild myself against the base, with the values of parameters supplied by the context
     * expression. This is used for transforming a standalone expression (e.g. the join criteria of a mapping)
     * into part of some larger expression. You normally would not call this directly, instead calling twist
     * See the comment there for more details"
     */
    public Expression twistedForBaseAndContext(Expression newBase, Expression context) {
        Expression twistedBase = getBaseExpression().twistedForBaseAndContext(newBase, context);
        return twistedBase.getTable(getTable());

    }

    /**
     * INTERNAL:
     * Used to print a debug form of the expression tree.
     */
    public void writeDescriptionOn(BufferedWriter writer) throws IOException {
        writer.write(getTable().toString());
        writer.write(tableAliasesDescription());
    }
}