expressionvalue.java

java 数据库 功能强大 效率高 SmallSQL Database is a free DBMS library for the Java(tm) platform. It runs on

/* =============================================================
 * SmallSQL : a free Java DBMS library for the Java(tm) platform
 * =============================================================
 *
 * (C) Copyright 2004-2006, by Volker Berlin.
 *
 * Project Info:  http://www.smallsql.de/
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------------
 * ExpressionValue.java
 * ---------------
 * Author: Volker Berlin
 * 
 */
package smallsql.database;

import java.math.BigDecimal;
import java.sql.*;


public class ExpressionValue extends Expression {

    private Object value;
    private int dataType;
	private int length;

    /**
     * Constructor is used from PreparedStatement parameters ( '?' in sql expression )
     */
    ExpressionValue(){
		super(VALUE);
        clear();
    }

	/**
	 * Constructor is used from Constructor GroupResult
	 */
	ExpressionValue(int type){
		super(type);
		switch(type){
			case GROUP_BY:
			case SUM:
			case FIRST:
			case LAST:
				clear();
				break;
			case MIN:
			case MAX:
				// set value to null
				break;
			case COUNT:
				value = new MutableInteger(0);
				dataType = SQLTokenizer.INT;
				break;
			default: throw new Error();
		}
	}
	

    /**
     * Constructor for static Expression i.e. 0x23, 67, 23.8, 'qwert'
     */
    ExpressionValue(Object value, int dataType ){
		super(VALUE);
        this.value      = value;
        this.dataType   = dataType;
    }
    

	/**
	 * Is used in GroupResult.
	 */
	public boolean equals(Object expr){
		if(!super.equals(expr)) return false;
		if(!(expr instanceof ExpressionValue)) return false;
		Object v = ((ExpressionValue)expr).value;
		if(v == value) return true;
		if(value == null) return false;
		return value.equals(v);
	}

	
/*==============================================================================
methods for Grouping
==============================================================================*/
	/**
	 * Accumulate the value of the expression to this aggregate function value. 
	 */
    void accumulate(Expression expr) throws Exception{
		int type = getType();
		if(type != GROUP_BY) expr = expr.getParams()[0];
		switch(type){
			case GROUP_BY:
			case FIRST:
				if(isEmpty()) set( expr.getObject(), expr.getDataType() );
				break;
			case LAST:
				set( expr.getObject(), expr.getDataType() );
				break;
			case COUNT:
				if(!expr.isNull()) ((MutableInteger)value).value++;
				break;
			case SUM:
				if(isEmpty()){
					initValue( expr );
				}else
				switch(dataType){
					case SQLTokenizer.TINYINT:
					case SQLTokenizer.SMALLINT:
					case SQLTokenizer.INT:
						((MutableInteger)value).value += expr.getInt();
						break;
					case SQLTokenizer.BIGINT:
						((MutableLong)value).value += expr.getLong();
						break;
					case SQLTokenizer.REAL:
						((MutableFloat)value).value += expr.getFloat();
						break;
					case SQLTokenizer.FLOAT:
					case SQLTokenizer.DOUBLE:
						((MutableDouble)value).value += expr.getDouble();
						break;
					case SQLTokenizer.NUMERIC:
					case SQLTokenizer.DECIMAL:
						MutableNumeric newValue = expr.getNumeric();
						if(newValue != null)
							((MutableNumeric)value).add( newValue );
						break;
					case SQLTokenizer.MONEY:
						((Money)value).value += expr.getMoney();
						break;						
					default: throw Utils.createSQLException("Unsupported data type "+SQLTokenizer.getKeyWord(dataType) +" for SUM function.");
				}
				break;
			case MAX:
				if(value == null){
					if(expr.isNull())
						dataType = expr.getDataType();
					else
						initValue( expr );
				}else if(!expr.isNull()){
					switch(dataType){
						case SQLTokenizer.TINYINT:
						case SQLTokenizer.SMALLINT:
						case SQLTokenizer.INT:
							((MutableInteger)value).value = Math.max( ((MutableInteger)value).value, expr.getInt());
							break;
						case SQLTokenizer.BIGINT:
							((MutableLong)value).value = Math.max( ((MutableLong)value).value, expr.getLong());
							break;
						case SQLTokenizer.REAL:
							((MutableFloat)value).value = Math.max( ((MutableFloat)value).value, expr.getFloat());
							break;
						case SQLTokenizer.FLOAT:
						case SQLTokenizer.DOUBLE:
							((MutableDouble)value).value = Math.max( ((MutableDouble)value).value, expr.getDouble());
							break;
						case SQLTokenizer.CHAR:
						case SQLTokenizer.VARCHAR:
						case SQLTokenizer.LONGVARCHAR:
							String str = expr.getString();
							if(String.CASE_INSENSITIVE_ORDER.compare( (String)value, str ) < 0) //cast needed for Compiler 1.5
								value = str;
							break;
						case SQLTokenizer.NUMERIC:
						case SQLTokenizer.DECIMAL:
							MutableNumeric newValue = expr.getNumeric();
							if(((MutableNumeric)value).compareTo( newValue ) < 0)
								value = newValue;
							break;
						case SQLTokenizer.MONEY:
							((Money)value).value = Math.max( ((Money)value).value, expr.getMoney());
							break;
						case SQLTokenizer.TIMESTAMP:
						case SQLTokenizer.SMALLDATETIME:
						case SQLTokenizer.DATE:
						case SQLTokenizer.TIME:
							((DateTime)value).time = Math.max( ((DateTime)value).time, expr.getLong());
							break;
						default: throw new Error(""+dataType);
					}
				}
				break;
			case MIN:
				if(value == null){
					if(expr.isNull())
						dataType = expr.getDataType();
					else
						initValue( expr );
				}else if(!expr.isNull()){
					switch(dataType){
						case SQLTokenizer.TINYINT:
						case SQLTokenizer.SMALLINT:
						case SQLTokenizer.INT:
							((MutableInteger)value).value = Math.min( ((MutableInteger)value).value, expr.getInt());
							break;
						case SQLTokenizer.BIGINT:
							((MutableLong)value).value = Math.min( ((MutableLong)value).value, expr.getLong());
							break;
						case SQLTokenizer.REAL:
							((MutableFloat)value).value = Math.min( ((MutableFloat)value).value, expr.getFloat());
							break;
						case SQLTokenizer.FLOAT:
						case SQLTokenizer.DOUBLE:
							((MutableDouble)value).value = Math.min( ((MutableDouble)value).value, expr.getDouble());
							break;
						case SQLTokenizer.CHAR:
						case SQLTokenizer.VARCHAR:
						case SQLTokenizer.LONGVARCHAR:
							String str = expr.getString();
							if(String.CASE_INSENSITIVE_ORDER.compare( (String)value, str ) > 0) //cast needed for Compiler 1.5
								value = str;
							break;
						case SQLTokenizer.NUMERIC:
						case SQLTokenizer.DECIMAL:
							MutableNumeric newValue = expr.getNumeric();
							if(((MutableNumeric)value).compareTo( newValue ) > 0)
								value = newValue;
							break;
						case SQLTokenizer.MONEY:
							((Money)value).value = Math.min( ((Money)value).value, expr.getMoney());
							break;
						case SQLTokenizer.TIMESTAMP:
						case SQLTokenizer.SMALLDATETIME:
						case SQLTokenizer.DATE:
						case SQLTokenizer.TIME:
							((DateTime)value).time = Math.min( ((DateTime)value).time, expr.getLong());
							break;
						default: throw new Error(""+dataType);
					}
				}
				break;
			default: throw new Error();
		}
	}

    
    /**
     * Init a summary field with a Mutable 
     * @param expr the expression that produce the values which should be summary
     * @throws Exception
     */
	private void initValue(Expression expr) throws Exception{
		dataType = expr.getDataType();
		switch(dataType){
			case SQLTokenizer.TINYINT:
			case SQLTokenizer.SMALLINT:
			case SQLTokenizer.INT:
				value = new MutableInteger(expr.getInt());
				break;
			case SQLTokenizer.BIGINT:
				value = new MutableLong(expr.getLong());
				break;
			case SQLTokenizer.REAL:
				value = new MutableFloat(expr.getFloat());
				break;
			case SQLTokenizer.FLOAT:
			case SQLTokenizer.DOUBLE:
				value = new MutableDouble(expr.getDouble());
				break;
			case SQLTokenizer.SMALLMONEY:
			case SQLTokenizer.MONEY:
				value = Money.createFromUnscaledValue(expr.getMoney());
				break;
			case SQLTokenizer.NUMERIC:
			case SQLTokenizer.DECIMAL:
				value = new MutableNumeric(expr.getNumeric());
				break;
			case SQLTokenizer.TIMESTAMP:
			case SQLTokenizer.SMALLDATETIME:
			case SQLTokenizer.DATE:
			case SQLTokenizer.TIME:
				value = new DateTime(expr.getLong(), dataType);
				break;
			default: 
				// is used for MAX and MIN
				value = expr.getObject();
		}
	}
/*==============================================================================
methods for PreparedStatement parameters
==============================================================================*/
    private static final Object EMPTY = new Object();
    final boolean isEmpty(){
        return value == EMPTY;
    }

    final void clear(){
        value = EMPTY;
    }
    

	final void set( Object value, int _dataType, int length ) throws SQLException{
		set( value, _dataType );
		this.length = length;
	}
	
	
    /**
     * 
     * @param newValue The new Value.
     * @param newDataType The data type of the new Value (One of the SQLTokenizer const). 
     * If the type is -1 then the data type is verify with many instanceof expressions.
     * @throws SQLException If the newValue is not a instance of a know class. 
     */
    final void set( Object newValue, int newDataType ) throws SQLException{
        this.value      = newValue;
        this.dataType   = newDataType;
        if(dataType < 0){
            if(newValue == null)
                this.dataType = SQLTokenizer.NULL;
            else
            if(newValue instanceof String)
                this.dataType = SQLTokenizer.VARCHAR;
            else
            if(newValue instanceof Byte)
                this.dataType = SQLTokenizer.TINYINT;
            else
            if(newValue instanceof Short)
                this.dataType = SQLTokenizer.SMALLINT;
            else
            if(newValue instanceof Integer)
                this.dataType = SQLTokenizer.INT;
            else