Quadcap Embeddable Database

com/quadcap/sql/Table.java

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package com.quadcap.sql;

/* Copyright 1999 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.ByteArrayOutputStream;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.Externalizable;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.OutputStream;

import java.util.BitSet;
import java.util.Hashtable;
import java.util.Vector;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import com.quadcap.sql.io.ObjectInputStream;
import com.quadcap.sql.io.ObjectOutputStream;

import com.quadcap.sql.index.Btree;

import com.quadcap.sql.file.BlockFile;
import com.quadcap.sql.file.ByteUtil;
import com.quadcap.sql.file.Datafile;
import com.quadcap.sql.file.Page;
import com.quadcap.sql.file.PageManager;
import com.quadcap.sql.file.RandomAccess;
import com.quadcap.sql.file.RandomAccessOutputStream;
import com.quadcap.sql.file.SubPageManager;

import com.quadcap.sql.types.Type;
import com.quadcap.sql.types.TypeBlob;
import com.quadcap.sql.types.TypeClob;
import com.quadcap.sql.types.Value;

import com.quadcap.util.ConfigNumber;
import com.quadcap.util.Debug;
import com.quadcap.util.Util;


/**
 * A single SQL base table.
 *
 * @author Stan Bailes
 */
public class Table extends TupleImpl implements Relation, Externalizable {
    // bit 0: table insert

    int                         modifiers       = 0;    
    Constraint[]                constraints     = new Constraint[0];
    transient boolean           underConstruction = false;

    // init: 0, if blobs: 1, else 2;
    transient int               hasBlobs        = 0;

    /**
     * Table modifiers, bit fields.  If temporary, either global or local
     * must be specified.
     */
    public static final int     TEMPORARY       = 1;
    public static final int     LOCAL           = 2;
    public static final int     GLOBAL          = 4;
    public static final int     STATEMENT_TEMP  = 8;

    /**
     * For in-memory mode, the table identity
     */
    long tableIdentity = 1;

    /**
     * Default constructor (required for deserialization)
     */
    public Table() {}
    
    /**
     * Explicit constructor
     */
    public Table(String tableName, int modifiers) {
        super(tableName);
        this.modifiers = modifiers;
    }

    /**
     * Get/Set the value of the 'is under construction' flag.  This is used to
     * determine when ADD CONSTRAINT really has work to do ;-)
     */
    public boolean isUnderConstruction() { return underConstruction; }

    /**
     * Set the value of the 'is under construction' flag.
     */
    public void setUnderConstruction(boolean v) { underConstruction = v; }

    /**
     * Return the modifier bits for this table
     */
    public int getModifiers() { return modifiers; }

    /**
     * Are any of this table's columns BLOB (or CLOB) types?
     */
    public boolean hasBlobs() throws SQLException {
        if (hasBlobs == 0) {
            hasBlobs = 2;
            for (int i = 1; hasBlobs == 2 && i <= getColumnCount(); i++) {
                Column c = getColumn(i);
                Type t = c.getType();
                if (t instanceof TypeBlob || t instanceof TypeClob) {
                    hasBlobs = 1;
                }
            }
        }
        return hasBlobs == 1;
    }

    /**
     * Read me from a stream
     */
    public void readExternal(ObjectInput in)
        throws IOException, ClassNotFoundException
    {
        super.readExternal(in);
        constraints = new Constraint[in.readInt()];
        for (int i = 0; i < constraints.length; i++) {
            constraints[i] = (Constraint)in.readObject();
            try {
                constraints[i].setTable(this);
            } catch (SQLException ex) {
                Debug.print(ex);
            }
        }
    }

    /**
     * Write me to a stream
     */
    public void writeExternal(ObjectOutput out) throws IOException {
        super.writeExternal(out);
        out.writeInt(constraints.length);
        for (int i = 0; i < constraints.length; i++) {
            out.writeObject(constraints[i]);
        }
    }

    /**
     * Add a column to the table;  called during initial table construction
     * only.
     */
    public void addColumn(Column col) throws SQLException {
        super.addColumn(col);
        Vector v = col.getConstraints();
        if (v != null) {
            for (int i = 0; i < v.size(); i++) {
                Constraint c = (Constraint)v.elementAt(i);
                c.setColumn(col);
            }
        }
    }

    /**
     * Return the specified table constraint (zero-based)
     */
    final public Constraint getConstraint(int num) {
        return constraints[num];
    }

    /**
     * Return the number of table constraints
     */
    final public int getNumConstraints() {
        return constraints.length;
    }

    /**
     * Get the constraint with the specified name
     *
     * XXX Maybe we should profile this sucker.  A hashtable?
     */
    public Constraint getConstraint(String name) {
        for (int i = 0; i < constraints.length; i++) {
            Constraint c = constraints[i];
            if (c.getName().equals(name)) {
                return c;
            }
        }
        return null;
    }

    /**
     * Return the table's primary key constraint, if it is defined,
     * otherwise return null.
     */
    public UniqueConstraint getPrimaryKey() {
        UniqueConstraint uc = null;
        for (int i = 0; i < constraints.length; i++) {
            Constraint c = constraints[i];
            if (c instanceof PrimaryKeyConstraint) {
                return (PrimaryKeyConstraint)c;
            } else if (uc == null && c instanceof UniqueConstraint) {
                uc = (UniqueConstraint)c;
            }
        }
        return uc;
    }

    /**
     * Generate a unique, semi-meaningful, name for this constratint,
     * in case the user didn't specify one.
     */
    public void nameConstraint(Constraint c) {
        String name = c.getName();
        if (name == null) {
            name = c.getClass().getName();
            int idx = name.lastIndexOf('.');
            if (idx > 0) name = name.substring(idx+1);
            name += "_";
            name += Integer.toString(constraints.length);
            c.setName(name);
        }
    }

    /**
     * Add a table constraint
     */
    public void addConstraint(Constraint c) throws SQLException {
        Constraint[] nc = new Constraint[constraints.length + 1];
        boolean added = false;
        for (int i = 0; i < constraints.length; i++) {
            Constraint ci = constraints[i];
            if (added) {
                nc[i+1] = ci;
            } else {
                if (c.getPriority() >= ci.getPriority()) {
                    nc[i] = ci;
                } else {
                    nc[i] = c;
                    nc[i+1] = ci;
                    added = true;
                }
            }
        }
        if (!added) nc[constraints.length] = c;
        nameConstraint(c);
        constraints = nc;
        c.setTable(this);
        final int notnull = ResultSetMetaData.columnNoNulls;
        if (c instanceof NotNullConstraint ||
            c instanceof PrimaryKeyConstraint) {
            int[] cols = c.getColumns();
            for (int i = 0; i < cols.length; i++) {
                getColumn(cols[i]).setNullable(notnull);
            }
        }
    }

    /**
     * Delete the specified table constraint.
     */
    public void deleteConstraint(String name)
        throws SQLException, IOException
    {
        int off = 0;
        for (int i = 0; i < constraints.length; i++) {
            if (constraints[i].getName().equals(name)) {
                off++;
            } else if (off > 0) {
                constraints[i-off] = constraints[i];
            }
        }
        if (off > 0) {
            Constraint[] nc = new Constraint[constraints.length - off];
            System.arraycopy(constraints, 0, nc, 0, nc.length);
            constraints = nc;
        } else {
            throw new SQLException("No constraint: " + name + " for table " +
                                   getName(), "42000");
        }
    }

    /**
     * Delete a column from this table, and reset any column-constraint
     * mappings
     */
    public void deleteColumn(int c) throws SQLException, IOException {
        super.deleteColumn(c);
        resetColumnConstraints();
    }

    /**
     * Reset any constraint-column mapping (typically after a column
     * has been added or dropped)
     */
    public void resetColumnConstraints() throws SQLException {
        final int num = getNumConstraints();
        for (int i = 0; i < num; i++) {
            Constraint con = getConstraint(i);
            con.resetColumns();
        }
    }
 
    /**
      * Convenience method to write a new row to the database
      */
    public static final long putRow(Session session, Tuple t, Row row)
        throws SQLException, IOException
    {
        return session.getDatabase().putRow(session, session.getFile(), t, row);
    }
    
//     /**
//       * Update the specified row
//       */
//      public final void writeRow(Session session, long rowId, Row row)
//      throws SQLException, IOException
//      {
//          //#ifdef TRACE
//          if (Trace.bit(11)) {
//              Debug.println("Table[" + getName() + "].putRow(" + row + ")");
//          }
//          //#endif
//      byte[] buf = LazyRow.writeRow(session, this, row);
//      session.getFile().updateBytes(rowId, buf);
//      }

//      /**
//       * Write (an already serialized) row to the database
//       */
//      public final static void writeRow(BlockFile file, long rowId, byte[] buf)
//      throws SQLException, IOException
//      {
//          final RandomAccess ra = file.getStream(rowId);
//          ra.resize(buf.length);
//          ra.write(0, buf, 0, buf.length);
//      }

    static final String strip(String s) {
        int idx = s.lastIndexOf(".");
        if (idx >= 0) s = s.substring(idx+1);
        return s;
    }

    Row getRow(Database db, long rowId) throws IOException, SQLException {
        LazyRow row = new LazyRow(getColumnCount());
        db.getRow(rowId, row, false);
        return row;
    }

    /**
     * Return a cursor on this table
     */
    public Cursor getCursor(Session session, Expression where,
                            String asName, Cursor outer)
        throws SQLException
    {
        try {
            session.getTableReadLock(getName());
            Hashtable t = getNames(where);
            IndexConstraint con = getIndexForNames(session, t);
            String qualName = asName;
            if (qualName == null) qualName = getName();
            Cursor c = new IndexCursor(this, session, con, where,
                                       qualName, outer);
            return c;
        } catch (IOException e) {
            throw DbException.wrapThrowable(e);
        }
    }

    public Cursor getCursor(Session session, Expression where,
                            String asName)
        throws SQLException
    {
        return getCursor(session, where, asName, null);
    }

    public IndexCursor getCursor(Session session, IndexConstraint notMe)
        throws SQLException
    {
        try {
            session.getTableReadLock(getName());
            IndexConstraint con = getAnyIndexBut(session, notMe);
            if (con == null) return null;
            return new IndexCursor(this, session, con, null, getName(), null);
        } catch (IOException e) {
            throw DbException.wrapThrowable(e);
        }
    }

    class GetNames implements ExpressionVisitor {
        Hashtable                       t = new Hashtable();
        public void visit(Expression ex) {
            String name = ex.getName();
            if (name != null) {
                t.put(name, name);
            } else {
                ex.visitSubExpressions(this);
            }
        }
    }

    Hashtable getNames(Expression ex) {
        GetNames get = new GetNames();
        if (ex != null) get.visit(ex);
        return get.t;
    }

    final IndexConstraint getAnyIndex(Session session)
        throws IOException, SQLException
    {
        return getIndexConstraint(session, null, null);
    }

    final IndexConstraint getIndexForNames(Session session, Hashtable names)
        throws IOException, SQLException
    {
        return getIndexConstraint(session, names, null);
    }

    final IndexConstraint getAnyIndexBut(Session session, IndexConstraint notMe)
        throws IOException, SQLException
    {
        return getIndexConstraint(session, null, notMe);
    }

    IndexConstraint getIndexConstraint(Session session, Hashtable names,
                                       IndexConstraint notMe)
        throws IOException, SQLException
    {
        // try to find, in this order:
        // a unique constraint matching an item in the where clause
        UniqueConstraint wcon = null;    
        // any index constraint matching an item in the where clause
        IndexConstraint icon = null;
        // any unique constraint
        UniqueConstraint ucon = null;
        // any index
        IndexConstraint acon = null;

        String sc = "";
        String nm = getName();
        int idx = nextUnquotedPeriod(nm);
        if (idx >= 0) {
            sc = nm.substring(0, idx);
            nm = nm.substring(idx+1);
        }

        for (int ci = 0; ci < constraints.length; ci++) {
            Constraint con = constraints[ci];
            if (con == notMe) continue;
            if (con instanceof IndexConstraint) {
                acon = (IndexConstraint)con;
                Vector cnames = con.getColumnNames();
                if (cnames == null) {
                    // bad news, skip out the back
                    //#ifdef DEBUG
                    throw new SQLException("Index constraint has no columns: "+
                                           con);
                    //#else
//-                    continue;
                    //#endif
                }
                boolean matched = false;
                if (names != null) {
                    matched = true;
                    for (int i = 0; matched && i < cnames.size(); i++) {
                        String cnam = cnames.get(i).toString();
                        if (names.get(cnam) == null &&
                            names.get(nm + "." + cnam) == null &&
                            names.get(sc + "." + nm + "." + cnam) == null) {
                            matched = false;
                        }
                    }
                }
                if (matched) {
                    if (acon instanceof UniqueConstraint) {
                        wcon = (UniqueConstraint)acon;
                    } else {
                        icon = acon;
                    }
                } else {
                    if (acon instanceof UniqueConstraint) {
                        ucon = (UniqueConstraint)acon;
                    }
                }
            }
        }
        
        if (wcon != null) return wcon;
        if (icon != null) return icon;
        if (ucon != null) return ucon;
        if (acon != null) return acon;

        // Don't throw an exception when trying to create first index.
        if (notMe == null) {
            throw new SQLException("No index", "42000");
        } else {
            return null;
        }
    }

    UniqueConstraint getIndexForColumns(int[] cols) throws SQLException {
        BitSet match = new BitSet();
        for (int i = 0; i < cols.length; i++) {
            match.set(cols[i]);
        }
        for (int i = 0; i < constraints.length; i++) {
            Constraint con = constraints[i];
            if (con instanceof UniqueConstraint) {
                int[] tcols = con.getColumns();
                BitSet tmatch = new BitSet();
                for (int j = 0; j < tcols.length; j++) {
                    tmatch.set(tcols[j]);
                }
                if (match.equals(tmatch)) return (UniqueConstraint)con;
            }
        }
        return null;
    }

    /**
     * My SQL type
     */
    public String getType() {
        if ((modifiers & TEMPORARY) != 0) {
            if ((modifiers & GLOBAL) != 0) {
                return "GLOBAL TEMPORARY";
            }
            if ((modifiers & LOCAL) != 0) {
                return "LOCAL TEMPORARY";
            }
        }
        return "TABLE"; 
    }

    /** (haiku-comment)
     * I am a table
     * and therefore updateable
     * @return true not false
     */
    public boolean isUpdatable() { return true; }

    //#ifdef DEBUG
    /**
     * String representation for debugging
     */
    public String toString() {
        StringBuffer sb = new StringBuffer(super.toString());
        sb.append("Constraints:\n");
        for (int i = 0; i < constraints.length; i++) {
            Constraint c = constraints[i];
            sb.append("   ");
            sb.append(String.valueOf(c));
            sb.append("\n");
        }
        return sb.toString();
    }
    //#endif

    public void insertRow(Session session, Row row)
        throws SQLException, IOException
    {
        TableOps.insertRow(session, this, row);
    }
    
}