sqlsmallint.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.iapi.types.SQLSmallint

   Copyright 1999, 2004 The Apache Software Foundation or its licensors, as applicable.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */

package org.apache.derby.iapi.types;

import org.apache.derby.iapi.reference.SQLState;

import org.apache.derby.iapi.services.io.ArrayInputStream;

import org.apache.derby.iapi.types.DataValueDescriptor;
import org.apache.derby.iapi.types.TypeId;
import org.apache.derby.iapi.types.NumberDataValue;
import org.apache.derby.iapi.types.BooleanDataValue;

import org.apache.derby.iapi.services.io.StoredFormatIds;
import org.apache.derby.iapi.services.io.Storable;

import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.services.sanity.SanityManager;

import org.apache.derby.iapi.services.cache.ClassSize;

import org.apache.derby.iapi.types.NumberDataType;
import org.apache.derby.iapi.types.SQLBoolean;

import java.io.ObjectOutput;
import java.io.ObjectInput;
import java.io.IOException;

import java.sql.ResultSet;
import java.sql.PreparedStatement;
import java.sql.SQLException;

/**
 * SQLSmallint satisfies the DataValueDescriptor
 * interfaces (i.e., OrderableDataType). It implements a smallint column, 
 * e.g. for storing a column value; it can be specified
 * when constructed to not allow nulls. Nullability cannot be changed
 * after construction, as it affects the storage size and mechanism.
 * <p>
 * Because OrderableDataType is a subtype of ValueColumn,
 * SQLSmallint can play a role in either a ValueColumn/Row
 * or a OrderableDataType/Row, interchangeably.
 * <p>
 * We assume the store has a flag for nullness of the value,
 * and simply return a 0-length array for the stored form
 * when the value is null.
 * <p>
 * PERFORMANCE: There are likely alot of performance improvements
 * possible for this implementation -- it new's Short
 * more than it probably wants to.
 */
public final class SQLSmallint
	extends NumberDataType
{
	/*
	 * DataValueDescriptor interface
	 * (mostly implemented in DataType)
	 */


        // JDBC is lax in what it permits and what it
	// returns, so we are similarly lax

	/** 
	 * @see DataValueDescriptor#getInt 
	 */
	public int	getInt()
	{
		return (int) value;
	}

	/** 
	 * @exception StandardException thrown on failure to convert
	 * @see DataValueDescriptor#getByte 
	 */
	public byte	getByte() throws StandardException
	{
		if (value > Byte.MAX_VALUE || value < Byte.MIN_VALUE)
			throw StandardException.newException(SQLState.LANG_OUTSIDE_RANGE_FOR_DATATYPE, "TINYINT");
		return (byte) value;
	}

	/** 
	 * @see DataValueDescriptor#getShort 
	 */
	public short	getShort()
	{
		return value;
	}

	/** 
	 * @see DataValueDescriptor#getLong 
	 */
	public long	getLong()
	{
		return (long) value;
	}

	/** 
	 * @see DataValueDescriptor#getFloat 
	 */
	public float	getFloat()
	{
		return (float) value;
	}

	/** 
	 * @see DataValueDescriptor#getDouble 
	 */
	public double	getDouble()
	{
		return (double) value;
	}

    // for lack of a specification: 0 or null is false,
    // all else is true
	/** 
	 * @see DataValueDescriptor#getBoolean 
	 */
	public boolean	getBoolean()
	{
		return (value != 0);
	}

	/** 
	 * @see DataValueDescriptor#getString 
	 */
	public String	getString()
	{
		if (isNull())
			return null;
		else
			return Short.toString(value);
	}

	/** 
	 * @see DataValueDescriptor#getLength 
	 */
	public int	getLength()
	{
		return SMALLINT_LENGTH;
	}

	/** 
	 * @see DataValueDescriptor#getObject 
	 */
	public Object	getObject() 
	{
		if (isNull())
			return null;
		else
			return new Integer(value);
	}

	// this is for DataType's error generator
	public String getTypeName()
	{
		return TypeId.SMALLINT_NAME;
	}

	/*
	 * Storable interface, implies Externalizable, TypedFormat
	 */


	/**
		Return my format identifier.

		@see org.apache.derby.iapi.services.io.TypedFormat#getTypeFormatId
	*/
	public int getTypeFormatId() {
		return StoredFormatIds.SQL_SMALLINT_ID;
	}

	/**
	 * always false for non-nullable columns
	 @see Storable#isNull
	*/
	public boolean isNull()
	{
		return isnull;
	}

	public void writeExternal(ObjectOutput out) throws IOException {

		// never called when value is null
		if (SanityManager.DEBUG)
			SanityManager.ASSERT(! isNull());

		out.writeShort(value);
	}

	/** @see java.io.Externalizable#readExternal */
	public void readExternalFromArray(ArrayInputStream in) throws IOException {

		value = in.readShort();
		isnull = false;
	}
	public void readExternal(ObjectInput in) throws IOException {

		value = in.readShort();
		isnull = false;
	}

	/**
	 * @see Storable#restoreToNull
	 *
	 */
	public void restoreToNull()
	{
		value = 0;
		isnull = true;
	}


	/** @exception StandardException		Thrown on error */
	protected int typeCompare(DataValueDescriptor arg) throws StandardException
	{
		/* neither are null, get the value */

		/* Do comparisons with ints to avoid overflow problems */
		int thisValue = this.getInt();
		int otherValue = arg.getInt();
		if (thisValue == otherValue)
			return 0;
		else if (thisValue > otherValue)
			return 1;
		else
			return -1;
	}

	/*
	 * DataValueDescriptor interface
	 */

	/** @see DataValueDescriptor#getClone */
	public DataValueDescriptor getClone()
	{
		return new SQLSmallint(value, isnull);
	}

	/**
	 * @see DataValueDescriptor#getNewNull
	 */
	public DataValueDescriptor getNewNull()
	{
		return new SQLSmallint();
	}

	/** 
	 * @see DataValueDescriptor#setValueFromResultSet 
	 *
	 * @exception SQLException		Thrown on error
	 */
	public void setValueFromResultSet(ResultSet resultSet, int colNumber,
									  boolean isNullable)
		throws SQLException
	{
		try {
			value = resultSet.getShort(colNumber);
			isnull = (isNullable && resultSet.wasNull());
		} catch (SQLException selq) {
			int i = resultSet.getInt(colNumber);
			value = (short) i;
			isnull = false;

		}
	}
	/**
		Set the value into a PreparedStatement.

		@exception SQLException Error setting value in PreparedStatement
	*/
	public final void setInto(PreparedStatement ps, int position) throws SQLException {

		if (isNull()) {
			ps.setNull(position, java.sql.Types.SMALLINT);
			return;
		}

		ps.setShort(position, value);
	}
	/**
		Set this value into a ResultSet for a subsequent ResultSet.insertRow
		or ResultSet.updateRow. This method will only be called for non-null values.

		@exception SQLException thrown by the ResultSet object
		@exception StandardException thrown by me accessing my value.
	*/
	public final void setInto(ResultSet rs, int position) throws SQLException, StandardException {
		rs.updateShort(position, value);
	}


	/*
	 * class interface
	 */

	/*
	 * constructors
	 */

	/**
		No-arg constructor, required by Formattable.
    // This constructor also gets used when we are
    // allocating space for a short.
	*/
	public SQLSmallint() 
	{
		isnull = true;
	}

	public SQLSmallint(short val)
	{
		value = val;
	}

	/* This constructor gets used for the getClone() method */
	public SQLSmallint(short val, boolean isnull)
	{
		value = val;
		this.isnull = isnull;
	}

	/**
		@exception StandardException thrown if string not accepted
	 */
	public void setValue(String theValue)
		throws StandardException
	{
		if (theValue == null)
		{
			value = 0;
			isnull = true;
		}
		else
		{
		    try {
		        value = Short.valueOf(theValue.trim()).shortValue();
			} catch (NumberFormatException nfe) {
			    throw invalidFormat();
			}
			isnull = false;
		}

	}

	public void setValue(short theValue)
	{
		value = theValue;
		isnull = false;
	}

	public void setValue(byte theValue)
	{
		value = theValue;
		isnull = false;
	}

	/**
		@exception StandardException if outsideRangeForSmallint
	 */
	public void setValue(int theValue) throws StandardException
	{
		if (theValue > Short.MAX_VALUE || theValue < Short.MIN_VALUE)
			throw StandardException.newException(SQLState.LANG_OUTSIDE_RANGE_FOR_DATATYPE, "SMALLINT");
		value = (short)theValue;
		isnull = false;
	}