/*
 * JBoss, Home of Professional Open Source.
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 * 
 * 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.
 */

/*
 */
package org.teiid.translator.jdbc.sybase;

import java.sql.Connection;
import java.sql.Date;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.teiid.core.types.BinaryType;
import org.teiid.core.util.StringUtil;
import org.teiid.language.Command;
import org.teiid.language.DerivedColumn;
import org.teiid.language.Expression;
import org.teiid.language.Function;
import org.teiid.language.Literal;
import org.teiid.language.SQLConstants;
import org.teiid.language.Select;
import org.teiid.logging.LogConstants;
import org.teiid.logging.LogManager;
import org.teiid.translator.ExecutionContext;
import org.teiid.translator.SourceSystemFunctions;
import org.teiid.translator.Translator;
import org.teiid.translator.TranslatorException;
import org.teiid.translator.TranslatorProperty;
import org.teiid.translator.TypeFacility;
import org.teiid.translator.jdbc.AliasModifier;
import org.teiid.translator.jdbc.ConvertModifier;
import org.teiid.translator.jdbc.EscapeSyntaxModifier;
import org.teiid.translator.jdbc.FunctionModifier;
import org.teiid.translator.jdbc.ModFunctionModifier;
import org.teiid.translator.jdbc.ParseFormatFunctionModifier;
import org.teiid.translator.jdbc.oracle.ConcatFunctionModifier;
import org.teiid.util.Version;


@Translator(name="sybase", description="A translator for Sybase Database")
public class SybaseExecutionFactory extends BaseSybaseExecutionFactory {

	public static final class SybaseFormatFunctionModifier extends
			ParseFormatFunctionModifier {
	    private Map<String, Object> formatMap;
	    
	    public SybaseFormatFunctionModifier(String prefix, Map<String, Object> formatMap) {
			super(prefix);
			this.formatMap = formatMap;
		}

		@Override
		protected void translateFormat(List<Object> result,
				Expression expression, String value) {
			Object format = translateFormat(value);
			if (format instanceof String) {
				result.add("convert("); //$NON-NLS-1$
				result.add(format);
				result.add(", "); //$NON-NLS-1$
				result.add(expression);
				result.add(")"); //$NON-NLS-1$
			} else {
				super.translateFormat(result, expression, value);
			}
		}

		@Override
		protected Object translateFormat(String format) {
			return formatMap.get(format);
		}
	}

	public static final Version TWELVE_5_3 = Version.getVersion("12.5.3"); //$NON-NLS-1$
	public static final Version TWELVE_5 = Version.getVersion("12.5"); //$NON-NLS-1$
	public static final Version FIFTEEN_0_2 = Version.getVersion("15.0.2"); //$NON-NLS-1$
	public static final Version FIFTEEN_5 = Version.getVersion("15.5"); //$NON-NLS-1$
	
	protected Map<String, Object> formatMap = new HashMap<String, Object>();
	protected boolean jtdsDriver;
	protected ConvertModifier convertModifier = new ConvertModifier();
	
	public SybaseExecutionFactory() {
		setSupportsFullOuterJoins(false);
		setMaxInCriteriaSize(250);
		setMaxDependentInPredicates(7);
		populateDateFormats();
	}
	
	protected void populateDateFormats() {
		formatMap.put("MM/dd/yy", 1); //$NON-NLS-1$
		formatMap.put("yy.MM.dd", 2); //$NON-NLS-1$
		formatMap.put("dd/MM/yy", 3); //$NON-NLS-1$
		formatMap.put("dd.MM.yy", 4); //$NON-NLS-1$
		formatMap.put("dd-MM-yy", 5); //$NON-NLS-1$
		formatMap.put("dd MMM yy", 6); //$NON-NLS-1$
		formatMap.put("MMM dd, yy", 7); //$NON-NLS-1$
		formatMap.put("MM-dd-yy", 10); //$NON-NLS-1$
		formatMap.put("yy/MM/dd", 11); //$NON-NLS-1$
		formatMap.put("yyMMdd", 12); //$NON-NLS-1$
		formatMap.put("yyddMM", 13); //$NON-NLS-1$
		formatMap.put("MM/yy/dd", 14); //$NON-NLS-1$
		formatMap.put("dd/yy/MM", 15); //$NON-NLS-1$
		formatMap.put("MMM dd yy HH:mm:ss", 16); //$NON-NLS-1$
		for (Map.Entry<String, Object> entry : new HashSet<Map.Entry<String, Object>>(formatMap.entrySet())) {
			formatMap.put(entry.getKey().replace("yy", "yyyy"), (Integer)entry.getValue() + 100); //$NON-NLS-1$ //$NON-NLS-2$
		}

		formatMap.put("MMM d yyyy hh:mma", 100); //$NON-NLS-1$
		formatMap.put("HH:mm:ss", 8); //$NON-NLS-1$
		formatMap.put("MMM d yyyy hh:mm:ss:SSSa", 109); //$NON-NLS-1$
		formatMap.put("hh:mma", 17); //$NON-NLS-1$
		formatMap.put("HH:mm", 18); //$NON-NLS-1$
		formatMap.put("hh:mm:ss:SSSa", 19); //$NON-NLS-1$
		formatMap.put("HH:mm:ss:SSS", 20); //$NON-NLS-1$
		formatMap.put("yy/MM/dd HH:mm:ss", 21); //$NON-NLS-1$
		formatMap.put("yy/MM/dd hh:mm:ssa", 22); //$NON-NLS-1$
		formatMap.put("yyyy-MM-dd'T'HH:mm:ss", 23); //$NON-NLS-1$
	}
    
    public void start() throws TranslatorException {
        super.start();
        
        registerFunctionModifier(SourceSystemFunctions.MOD, new ModFunctionModifier("%", getLanguageFactory())); //$NON-NLS-1$
        if (nullPlusNonNullIsNull()) {
        	registerFunctionModifier(SourceSystemFunctions.CONCAT, new AliasModifier("+")); //$NON-NLS-1$
        } else {
        	registerFunctionModifier(SourceSystemFunctions.CONCAT, new ConcatFunctionModifier(getLanguageFactory()) {
        		@Override
        		public List<?> translate(Function function) {
        			function.setName("+"); //$NON-NLS-1$
        			return super.translate(function);
        		}
        	});
        }
        registerFunctionModifier(SourceSystemFunctions.LPAD, new FunctionModifier() {
            @Override
            public List<?> translate(Function function) {
                List<Expression> params = function.getParameters();
                return Arrays.asList("RIGHT(REPLICATE(", //$NON-NLS-1$
                        params.size()>2?params.get(2):new Literal(" ", TypeFacility.RUNTIME_TYPES.STRING), ", ", //$NON-NLS-1$ //$NON-NLS-2$
                                params.get(1), ") + ", params.get(0), ", ", params.get(1), ")"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
            }
        }); 
        registerFunctionModifier(SourceSystemFunctions.RPAD, new FunctionModifier() {
            @Override
            public List<?> translate(Function function) {
                List<Expression> params = function.getParameters();
                return Arrays.asList("LEFT(", params.get(0), " + REPLICATE(", //$NON-NLS-1$ //$NON-NLS-2$ 
                        params.size()>2?params.get(2):new Literal(" ", TypeFacility.RUNTIME_TYPES.STRING), ", ", //$NON-NLS-1$ //$NON-NLS-2$ 
                                params.get(1), "), ", params.get(1), ")"); //$NON-NLS-1$ //$NON-NLS-2$
            }
        });
        registerFunctionModifier(SourceSystemFunctions.LCASE, new AliasModifier("lower")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.IFNULL, new AliasModifier("isnull")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.UCASE, new AliasModifier("upper")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.REPEAT, new AliasModifier("replicate")); //$NON-NLS-1$
        registerFunctionModifier(SourceSystemFunctions.SUBSTRING, new SubstringFunctionModifier(getLanguageFactory()));
        registerFunctionModifier(SourceSystemFunctions.DAYNAME, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.MONTHNAME, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.DAYOFWEEK, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.DAYOFYEAR, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.DAYOFMONTH, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.HOUR, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.MINUTE, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.QUARTER, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.SECOND, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.WEEK, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.LENGTH, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.ATAN2, new EscapeSyntaxModifier());
        registerFunctionModifier(SourceSystemFunctions.TIMESTAMPADD, new EscapeSyntaxModifier() {
			
			@Override
			public List<?> translate(Function function) {
				if (!isFracSeconds(function)) {
					return super.translate(function);
				}
				//convert from billionths to thousandths
				return Arrays.asList("dateadd(millisecond, ", function.getParameters().get(1), "/1000000, ", function.getParameters().get(2), ")"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			}
		});
        registerFunctionModifier(SourceSystemFunctions.TIMESTAMPDIFF, new EscapeSyntaxModifier() {
			
			@Override
			public List<?> translate(Function function) {
				if (!isFracSeconds(function)) {
					return super.translate(function);
				}
				//convert from billionths to thousandths
				return Arrays.asList("datediff(millisecond, ", function.getParameters().get(1), ",", function.getParameters().get(2), ")*1000000"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			}
		});
        
        //add in type conversion
        convertModifier.setBooleanNullable(booleanNullable());
        //boolean isn't treated as bit, since it doesn't support null
        //byte is treated as smallint, since tinyint is unsigned
    	convertModifier.addTypeMapping("smallint", FunctionModifier.BYTE, FunctionModifier.SHORT); //$NON-NLS-1$
    	convertModifier.addTypeMapping("int", FunctionModifier.INTEGER); //$NON-NLS-1$
    	convertModifier.addTypeMapping("numeric(19,0)", FunctionModifier.LONG); //$NON-NLS-1$
    	convertModifier.addTypeMapping("real", FunctionModifier.FLOAT); //$NON-NLS-1$
    	convertModifier.addTypeMapping("double precision", FunctionModifier.DOUBLE); //$NON-NLS-1$
    	convertModifier.addTypeMapping("numeric(38, 0)", FunctionModifier.BIGINTEGER); //$NON-NLS-1$
    	convertModifier.addTypeMapping("numeric(38, 19)", FunctionModifier.BIGDECIMAL); //$NON-NLS-1$
    	convertModifier.addTypeMapping("char(1)", FunctionModifier.CHAR); //$NON-NLS-1$
    	convertModifier.addTypeMapping("varchar(4000)", FunctionModifier.STRING); //$NON-NLS-1$
    	convertModifier.addConvert(FunctionModifier.TIMESTAMP, FunctionModifier.DATE, new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				List<Object> result = new ArrayList<Object>();
				result.add("cast("); //$NON-NLS-1$
				result.addAll(convertDateToString(function));
				result.add(" AS datetime)"); //$NON-NLS-1$
				return result;
			}
		});
    	convertModifier.addConvert(FunctionModifier.TIME, FunctionModifier.STRING, new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				return convertTimeToString(function);
			}
		}); 
    	convertModifier.addConvert(FunctionModifier.DATE, FunctionModifier.STRING, new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				return convertDateToString(function);
			}
		});
    	convertModifier.addConvert(FunctionModifier.TIMESTAMP, FunctionModifier.STRING, new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				return convertTimestampToString(function);
			}
		});
    	convertModifier.addNumericBooleanConversions();
    	registerFunctionModifier(SourceSystemFunctions.CONVERT, convertModifier);
		registerFunctionModifier(SourceSystemFunctions.PARSETIMESTAMP, new SybaseFormatFunctionModifier("CONVERT(DATETIME, ", formatMap)); //$NON-NLS-1$
		registerFunctionModifier(SourceSystemFunctions.FORMATTIMESTAMP, new SybaseFormatFunctionModifier("CONVERT(VARCHAR, ", formatMap)); //$NON-NLS-1$
    }

	private void handleTimeConversions() {
		if (!hasTimeType()) {
    		convertModifier.addTypeMapping("datetime", FunctionModifier.DATE, FunctionModifier.TIME, FunctionModifier.TIMESTAMP); //$NON-NLS-1$
        	convertModifier.addConvert(FunctionModifier.TIMESTAMP, FunctionModifier.TIME, new FunctionModifier() {
    			@Override
    			public List<?> translate(Function function) {
    				List<Object> result = new ArrayList<Object>();
    				result.add("cast("); //$NON-NLS-1$
    				boolean needsEnd = false;
    				if (!nullPlusNonNullIsNull() && !ConcatFunctionModifier.isNotNull(function.getParameters().get(0))) {
    					result.add("CASE WHEN "); //$NON-NLS-1$
    					result.add(function.getParameters().get(0));
    					result.add(" IS NOT NULL THEN "); //$NON-NLS-1$
    					needsEnd = true;
    				} 
    				result.add("'1970-01-01 ' + "); //$NON-NLS-1$
    				result.addAll(convertTimeToString(function));
    				if (needsEnd) {
    					result.add(" END"); //$NON-NLS-1$
    				}
    				result.add(" AS datetime)"); //$NON-NLS-1$
    				return result;
    			}
    		});
    	} else {
    		convertModifier.addTypeMapping("datetime", FunctionModifier.DATE, FunctionModifier.TIMESTAMP); //$NON-NLS-1$
    		convertModifier.addTypeMapping("time", FunctionModifier.TIME); //$NON-NLS-1$
    	}
	}
    
	private List<Object> convertTimeToString(Function function) {
		return Arrays.asList("convert(varchar, ", function.getParameters().get(0), ", 8)"); //$NON-NLS-1$ //$NON-NLS-2$
	}
    
    protected List<Object> convertDateToString(Function function) {
		return Arrays.asList("stuff(stuff(convert(varchar, ", function.getParameters().get(0), ", 102), 5, 1, '-'), 8, 1, '-')"); //$NON-NLS-1$ //$NON-NLS-2$
	}
    
    //TODO: this looses the milliseconds
	protected List<?> convertTimestampToString(Function function) {
		LinkedList<Object> result = new LinkedList<Object>();
		result.addAll(convertDateToString(function));
		result.add('+');
		result.addAll(convertTimeToString(function));
		return result;
	}
    
    @Override
    public List<String> getSupportedFunctions() {
        List<String> supportedFunctions = new ArrayList<String>();
        supportedFunctions.addAll(super.getSupportedFunctions());
        supportedFunctions.add("ABS"); //$NON-NLS-1$
        supportedFunctions.add("ACOS"); //$NON-NLS-1$
        supportedFunctions.add("ASIN"); //$NON-NLS-1$
        supportedFunctions.add("ATAN"); //$NON-NLS-1$
        supportedFunctions.add("ATAN2"); //$NON-NLS-1$
        supportedFunctions.add("COS"); //$NON-NLS-1$
        supportedFunctions.add("COT"); //$NON-NLS-1$
        supportedFunctions.add("DEGREES"); //$NON-NLS-1$
        supportedFunctions.add("EXP"); //$NON-NLS-1$
        supportedFunctions.add("FLOOR"); //$NON-NLS-1$
        supportedFunctions.add("LOG"); //$NON-NLS-1$
        supportedFunctions.add("LOG10"); //$NON-NLS-1$
        supportedFunctions.add("MOD"); //$NON-NLS-1$
        supportedFunctions.add("PI"); //$NON-NLS-1$
        supportedFunctions.add("POWER"); //$NON-NLS-1$
        supportedFunctions.add("RADIANS"); //$NON-NLS-1$
        supportedFunctions.add("SIGN"); //$NON-NLS-1$
        supportedFunctions.add("SIN"); //$NON-NLS-1$
        supportedFunctions.add("SQRT"); //$NON-NLS-1$
        supportedFunctions.add("TAN"); //$NON-NLS-1$
        supportedFunctions.add("ASCII"); //$NON-NLS-1$
        supportedFunctions.add("CHAR"); //$NON-NLS-1$
        supportedFunctions.add("CHR"); //$NON-NLS-1$
        supportedFunctions.add("CONCAT"); //$NON-NLS-1$
        supportedFunctions.add("||"); //$NON-NLS-1$
        supportedFunctions.add("LCASE"); //$NON-NLS-1$
        supportedFunctions.add("LEFT"); //$NON-NLS-1$
        supportedFunctions.add("LENGTH"); //$NON-NLS-1$
        supportedFunctions.add("LOWER"); //$NON-NLS-1$
        supportedFunctions.add("LPAD"); //$NON-NLS-1$
        supportedFunctions.add("LTRIM"); //$NON-NLS-1$
        supportedFunctions.add("REPEAT"); //$NON-NLS-1$
        //supportedFunctions.add("RAND"); //$NON-NLS-1$
        supportedFunctions.add("RIGHT"); //$NON-NLS-1$
        supportedFunctions.add("RTRIM"); //$NON-NLS-1$
        supportedFunctions.add("SPACE"); //$NON-NLS-1$
        supportedFunctions.add("SUBSTRING"); //$NON-NLS-1$
        supportedFunctions.add("UCASE"); //$NON-NLS-1$
        supportedFunctions.add("UPPER"); //$NON-NLS-1$
        //supportedFunctons.add("CURDATE"); //$NON-NLS-1$
        //supportedFunctons.add("CURTIME"); //$NON-NLS-1$
        supportedFunctions.add("DAYNAME"); //$NON-NLS-1$
        supportedFunctions.add("DAYOFMONTH"); //$NON-NLS-1$
        supportedFunctions.add("DAYOFWEEK"); //$NON-NLS-1$
        supportedFunctions.add("DAYOFYEAR"); //$NON-NLS-1$
        supportedFunctions.add("HOUR"); //$NON-NLS-1$
        supportedFunctions.add("MINUTE"); //$NON-NLS-1$
        supportedFunctions.add("MONTH"); //$NON-NLS-1$
        supportedFunctions.add("MONTHNAME"); //$NON-NLS-1$
        //supportedFunctions.add("NOW"); //$NON-NLS-1$
        supportedFunctions.add("QUARTER"); //$NON-NLS-1$
        supportedFunctions.add("RPAD"); //$NON-NLS-1$
        supportedFunctions.add("SECOND"); //$NON-NLS-1$
        supportedFunctions.add("TIMESTAMPADD"); //$NON-NLS-1$
        supportedFunctions.add("TIMESTAMPDIFF"); //$NON-NLS-1$
        //not an iso calculation
        //supportedFunctions.add("WEEK"); //$NON-NLS-1$
        supportedFunctions.add("YEAR"); //$NON-NLS-1$
        supportedFunctions.add("CAST"); //$NON-NLS-1$
        supportedFunctions.add("CONVERT"); //$NON-NLS-1$
        supportedFunctions.add("IFNULL"); //$NON-NLS-1$
        supportedFunctions.add("NVL");      //$NON-NLS-1$ 
        supportedFunctions.add(SourceSystemFunctions.PARSETIMESTAMP);
        supportedFunctions.add(SourceSystemFunctions.FORMATTIMESTAMP);
        return supportedFunctions;
    }
    
    @Override
    public boolean supportsInlineViews() {
        return true;
    }

    @Override
    public boolean supportsFunctionsInGroupBy() {
        return true;
    }
    
    @Override
    public int getMaxFromGroups() {
        return 50;
    } 
    
    @Override
    public boolean supportsAggregatesEnhancedNumeric() {
    	return getVersion().compareTo(FIFTEEN_0_2) >= 0;
    }
    
    public boolean nullPlusNonNullIsNull() {
    	return false;
    }
    
    public boolean booleanNullable() {
    	return false;
    }
    
    @Override
    public String translateLiteralTimestamp(Timestamp timestampValue) {
    	return "CAST('" + formatDateValue(timestampValue) +"' AS DATETIME)"; //$NON-NLS-1$ //$NON-NLS-2$
    }
    
    @Override
    public String translateLiteralDate(Date dateValue) {
    	return "CAST('" + formatDateValue(dateValue) +"' AS DATE)"; //$NON-NLS-1$ //$NON-NLS-2$
    }
    
	private boolean isFracSeconds(Function function) {
		Expression e = function.getParameters().get(0);
		return (e instanceof Literal && SQLConstants.NonReserved.SQL_TSI_FRAC_SECOND.equalsIgnoreCase((String)((Literal)e).getValue()));
	}
	
	@Override
	public boolean supportsRowLimit() {
		return (getVersion().getMajorVersion() == 12 && getVersion().compareTo(TWELVE_5_3) >= 0) || getVersion().compareTo(FIFTEEN_0_2) >=0; //$NON-NLS-1$
	}

	@TranslatorProperty(display="JTDS Driver", description="True if the driver is the JTDS driver",advanced=true)
	public boolean isJtdsDriver() {
		return jtdsDriver;
	}
	
	public void setJtdsDriver(boolean jtdsDriver) {
		this.jtdsDriver = jtdsDriver;
	}
	
	protected boolean setFetchSize() {
		return isJtdsDriver();
	}
	
	@Override
	public void setFetchSize(Command command, ExecutionContext context,
			Statement statement, int fetchSize) throws SQLException {
		if (!setFetchSize()) {
			return;
		}
		super.setFetchSize(command, context, statement, fetchSize);
	}
	
	@Override
	public void initCapabilities(Connection connection)
			throws TranslatorException {
		super.initCapabilities(connection);
		if (!jtdsDriver && connection != null) {
			try {
				jtdsDriver = StringUtil.indexOfIgnoreCase(connection.getMetaData().getDriverName(), "jtds") != -1; //$NON-NLS-1$
			} catch (SQLException e) {
				LogManager.logDetail(LogConstants.CTX_CONNECTOR, e, "Could not automatically determine if the jtds driver is in use"); //$NON-NLS-1$
			}
		}
		handleTimeConversions();
	}
	
	@Override
	protected boolean usesDatabaseVersion() {
		return true;
	}
	
    @Override
    public boolean supportsSelectWithoutFrom() {
    	return true;
    }
    
    @Override
    public String getHibernateDialectClassName() {
    	if (getVersion().compareTo(FIFTEEN_0_2) >= 0) {
    		return "org.hibernate.dialect.SybaseASE15Dialect"; //$NON-NLS-1$
    	}
    	return "org.hibernate.dialect.Sybase11Dialect"; //$NON-NLS-1$
    }
    
    @Override
    public boolean supportsGroupByRollup() {
    	//TODO: there is support in SQL Anywhere/IQ, but not ASE
    	return false;
    }
    
    @Override
    public boolean useUnicodePrefix() {
    	return true;
    }
    
    @Override
    public boolean supportsOnlyFormatLiterals() {
        return true;
    }
    
    @Override
    public boolean supportsFormatLiteral(String literal,
    		org.teiid.translator.ExecutionFactory.Format format) {
    	if (format == Format.NUMBER) {
    		return false; //TODO: add support
    	}
    	return formatMap.containsKey(literal);
    }
    
    @Override
    public List<?> translateCommand(Command command, ExecutionContext context) {
    	if (!supportsLiteralOnlyWithGrouping() && (command instanceof Select)) {
	    	Select select = (Select)command;
	    	if (select.getGroupBy() != null && select.getDerivedColumns().size() == 1) {
	    		DerivedColumn dc = select.getDerivedColumns().get(0);
	    		if (dc.getExpression() instanceof Literal) {
	    			dc.setExpression(select.getGroupBy().getElements().get(0));
	    		}
	    	}
    	}
    	return super.translateCommand(command, context);
    }
    
    public boolean supportsLiteralOnlyWithGrouping() {
    	return false;
    }
    
    @Override
    public String translateLiteralBinaryType(BinaryType obj) {
    	return "0x" + obj; //$NON-NLS-1$
    }
    
}
