Created instance class for configuration preventing static Tomcat test case failures

h2/src/docsrc/help/help.csv

@@ -1181,7 +1181,7 @@ Emulation settings can be appended to the database URL:
 
 It is not recommended to use overly restrictive settings as system 
 columns can accidentally get their identifiers truncated leading to 
-undefined behavior.
+undefined behavior. A minimum value of 30 is enforced.
 ","
 -- Emulate popular database settings
 SET COLUMN_NAME_RULES=EMULATE=ORACLE128 -- Emulate Oracle 128 character column identifiers
@@ -1189,10 +1189,11 @@ SET COLUMN_NAME_RULES=EMULATE=ORACLE30; -- Emulate Oracle 30 character column id
 SET COLUMN_NAME_RULES=EMULATE=POSTGRES; -- Emulate Postgres
 SET COLUMN_NAME_RULES=DEFAULT; -- Reset back to default H2 allow-anything rules
 -- Custom settings
-SET COLUMN_NAME_RULES=MAX_IDENTIFIER_LENGTH = 10; -- Custom configure max identifier length
+SET COLUMN_NAME_RULES=MAX_IDENTIFIER_LENGTH = 30; -- Custom configure max identifier length (minimum value is 30)
 SET COLUMN_NAME_RULES=REGULAR_EXPRESSION_MATCH_ALLOWED = '[A-Za-z0-9_]+';  -- Custom configure Java RegEx for allowed characters
 SET COLUMN_NAME_RULES=REGULAR_EXPRESSION_MATCH_DISALLOWED = '[^A-Za-z0-9_]+'; -- Custom configure Java RegEx for disallowed characters
 SET COLUMN_NAME_RULES=DEFAULT_COLUMN_NAME_PATTERN = '_unnamed$$'; -- Custom configure default column name, $$ is replaced by column Nth ordinal
+SET COLUMN_NAME_RULES=GENERATE_UNIQUE_COLUMN_NAMES = 1; -- Generate unique column names (default is 0, meaning false)
 "
 
 "Commands (Other)","SET CLUSTER","

h2/src/main/org/h2/command/Parser.java

@@ -5269,12 +5269,13 @@ public class Parser {
         // array of length 1 to receive extra 'output' field in addition to
         // return value
         querySQLOutput[0] = StringUtils.cache(theQuery.getPlanSQL());
+        ColumnNamer columnNamer = new ColumnNamer(theQuery.getSession());
         ArrayList<Expression> withExpressions = theQuery.getExpressions();
         for (int i = 0; i < withExpressions.size(); ++i) {
             Expression columnExp = withExpressions.get(i);
             // use the passed in column name if supplied, otherwise use alias (if found) otherwise use column name
             // derived from column expression
-            String columnName = ColumnNamer.getColumnName(columnExp,i,cols).replace("\n", " ").replace("\r", " ");
+            String columnName = columnNamer.getColumnName(columnExp,i,cols);
             columnTemplateList.add(new Column(columnName,
                     columnExp.getType()));
 

h2/src/main/org/h2/command/ddl/CreateTable.java

@@ -231,10 +231,11 @@ public class CreateTable extends SchemaCommand {
     private void generateColumnsFromQuery() {
         int columnCount = asQuery.getColumnCount();
         ArrayList<Expression> expressions = asQuery.getExpressions();
+        ColumnNamer columnNamer= new ColumnNamer(session);
         for (int i = 0; i < columnCount; i++) {
             Expression expr = expressions.get(i);
             int type = expr.getType();
-            String name = ColumnNamer.getColumnName(expr,i,expr.getAlias());
+            String name = columnNamer.getColumnName(expr,i,expr.getAlias());
             long precision = expr.getPrecision();
             int displaySize = expr.getDisplaySize();
             DataType dt = DataType.getDataType(type);

h2/src/main/org/h2/command/dml/Select.java

@@ -840,10 +840,13 @@ public class Select extends Query {
             sort = prepareOrder(orderList, expressions.size());
             orderList = null;
         }
+        ColumnNamer columnNamer= new ColumnNamer(session);        
         for (int i = 0; i < expressions.size(); i++) {
             Expression e = expressions.get(i);
-            if(!ColumnNamer.isAllowableColumnName(e.getAlias())){
-                String columnName = ColumnNamer.getColumnName(e,i,e.getAlias());
+            String proposedColumnName = e.getAlias();
+            String columnName = columnNamer.getColumnName(e,i,proposedColumnName);
+            // if the name changed, create an alias
+            if(!columnName.equals(proposedColumnName)){
                 e = new Alias(e,columnName,true);
             }
             expressions.set(i, e.optimize(session));

h2/src/main/org/h2/command/dml/SelectListColumnResolver.java

@@ -36,9 +36,10 @@ public class SelectListColumnResolver implements ColumnResolver {
         columns = new Column[columnCount];
         expressions = new Expression[columnCount];
         ArrayList<Expression> columnList = select.getExpressions();
+        ColumnNamer columnNamer= new ColumnNamer(select.getSession());                
         for (int i = 0; i < columnCount; i++) {
             Expression expr = columnList.get(i);
-            String columnName = ColumnNamer.getColumnName(expr, i, expr.getAlias());
+            String columnName = columnNamer.getColumnName(expr, i, expr.getAlias());
             Column column = new Column(columnName, Value.NULL);
             column.setTable(null, i);
             columns[i] = column;

h2/src/main/org/h2/command/dml/SelectUnion.java

@@ -330,6 +330,7 @@ public class SelectUnion extends Query {
         expressions = New.arrayList();
         ArrayList<Expression> le = left.getExpressions();
         ArrayList<Expression> re = right.getExpressions();
+        ColumnNamer columnNamer= new ColumnNamer(session);                        
         for (int i = 0; i < len; i++) {
             Expression l = le.get(i);
             Expression r = re.get(i);
@@ -337,7 +338,7 @@ public class SelectUnion extends Query {
             long prec = Math.max(l.getPrecision(), r.getPrecision());
             int scale = Math.max(l.getScale(), r.getScale());
             int displaySize = Math.max(l.getDisplaySize(), r.getDisplaySize());
-            String columnName = ColumnNamer.getColumnName(l,i,l.getAlias());
+            String columnName = columnNamer.getColumnName(l,i,l.getAlias());
             Column col = new Column(columnName, type, prec, scale, displaySize);
             Expression e = new ExpressionColumn(session.getDatabase(), col);
             expressions.add(e);

h2/src/main/org/h2/command/dml/Set.java

@@ -23,7 +23,7 @@ import org.h2.result.RowFactory;
 import org.h2.schema.Schema;
 import org.h2.table.Table;
 import org.h2.tools.CompressTool;
-import org.h2.util.ColumnNamer;
+import org.h2.util.ColumnNamerConfiguration;
 import org.h2.util.JdbcUtils;
 import org.h2.util.StringUtils;
 import org.h2.value.CompareMode;
@@ -538,7 +538,10 @@ public class Set extends Prepared {
             
         case SetTypes.COLUMN_NAME_RULES: {
             session.getUser().checkAdmin();
-            ColumnNamer.configure(expression.getColumnName());
+            if(session.getColumnNamerConfiguration()==null){
+                session.setColumnNamerConfiguration(ColumnNamerConfiguration.getDefault());
+            }
+            session.getColumnNamerConfiguration().configure(expression.getColumnName());
            break;
         }
                         

h2/src/main/org/h2/engine/Session.java

@@ -42,6 +42,7 @@ import org.h2.table.SubQueryInfo;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
 import org.h2.table.TableType;
+import org.h2.util.ColumnNamerConfiguration;
 import org.h2.util.New;
 import org.h2.util.SmallLRUCache;
 import org.h2.value.Value;
@@ -126,6 +127,7 @@ public class Session extends SessionWithState {
     private boolean joinBatchEnabled;
     private boolean forceJoinOrder;
     private boolean lazyQueryExecution;
+    private ColumnNamerConfiguration columnNamerConfiguration;
     /**
      * Tables marked for ANALYZE after the current transaction is committed.
      * Prevents us calling ANALYZE repeatedly in large transactions.
@@ -162,6 +164,7 @@ public class Session extends SessionWithState {
         this.lockTimeout = setting == null ?
                 Constants.INITIAL_LOCK_TIMEOUT : setting.getIntValue();
         this.currentSchemaName = Constants.SCHEMA_MAIN;
+        this.columnNamerConfiguration = ColumnNamerConfiguration.getDefault();
     }
 
     public void setLazyQueryExecution(boolean lazyQueryExecution) {
@@ -1751,4 +1754,12 @@ public class Session extends SessionWithState {
         }
 
     }
+
+    public ColumnNamerConfiguration getColumnNamerConfiguration() {
+        return columnNamerConfiguration;
+    }
+
+    public void setColumnNamerConfiguration(ColumnNamerConfiguration columnNamerConfiguration) {
+        this.columnNamerConfiguration = columnNamerConfiguration;
+    }
 }

h2/src/main/org/h2/table/TableView.java

@@ -163,6 +163,7 @@ public class TableView extends Table {
             tables = New.arrayList(query.getTables());
             ArrayList<Expression> expressions = query.getExpressions();
             ArrayList<Column> list = New.arrayList();
+            ColumnNamer columnNamer= new ColumnNamer(session);                        
             for (int i = 0, count = query.getColumnCount(); i < count; i++) {
                 Expression expr = expressions.get(i);
                 String name = null;
@@ -174,7 +175,7 @@ public class TableView extends Table {
                 if (name == null) {
                     name = expr.getAlias();
                 }
-                name = ColumnNamer.getColumnName(expr,i,name);
+                name = columnNamer.getColumnName(expr,i,name);
                 if (type == Value.UNKNOWN) {
                     type = expr.getType();
                 }

h2/src/main/org/h2/util/ColumnNamer.java

 package org.h2.util;
 
+import java.util.HashSet;
+import java.util.Set;
 import java.util.regex.Matcher;
-import java.util.regex.Pattern;
+import org.h2.engine.Session;
 import org.h2.expression.Expression;
-import org.h2.message.DbException;
+
 
 public class ColumnNamer {
  
     private static final String DEFAULT_COLUMN_NAME = "DEFAULT";
-    private static final String DEFAULT_COMMAND = "DEFAULT";
-    private static final String REGULAR_EXPRESSION_MATCH_DISALLOWED = "REGULAR_EXPRESSION_MATCH_DISALLOWED = ";
-    private static final String REGULAR_EXPRESSION_MATCH_ALLOWED = "REGULAR_EXPRESSION_MATCH_ALLOWED = ";
-    private static final String DEFAULT_COLUMN_NAME_PATTERN = "DEFAULT_COLUMN_NAME_PATTERN = ";
-    private static final String MAX_IDENTIFIER_LENGTH = "MAX_IDENTIFIER_LENGTH = ";
-    private static final String EMULATE_COMMAND = "EMULATE = ";
 
+    private ColumnNamerConfiguration configuration;
+    private Session session;
+    private Set<String> existingColumnNames = new HashSet<String>();
+
+    public ColumnNamer(Session session) {
+        this.session = session;
+        if(this.session!=null && this.session.getColumnNamerConfiguration()!=null){
+            // use original from session
+            this.configuration = this.session.getColumnNamerConfiguration();
+        }
+        else{
+            // detached namer, create new
+            this.configuration = ColumnNamerConfiguration.getDefault();
+            if(session!=null){
+                session.setColumnNamerConfiguration(this.configuration);
+            }
+        }
+    }
     /**
      * Create a standardized column name that isn't null and doesn't have a CR/LF in it.
      * @param columnExp the column expression
      * @param indexOfColumn index of column in below array
      * @return
      */
-    public static String getColumnName(Expression expr, int indexOfColumn) {
+    public String getColumnName(Expression expr, int indexOfColumn) {
         return getColumnName(expr,indexOfColumn,(String) null);
     }
     /**
@@ -31,7 +45,7 @@ public class ColumnNamer {
      * @param columnNameOverides array of overriding column names
      * @return the new column name
      */
-    public static String getColumnName(Expression columnExp, int indexOfColumn, String[] columnNameOverides){
+    public String getColumnName(Expression columnExp, int indexOfColumn, String[] columnNameOverides){
         String columnNameOverride = null;
         if (columnNameOverides != null && columnNameOverides.length > indexOfColumn){
             columnNameOverride = columnNameOverides[indexOfColumn];
@@ -46,7 +60,7 @@ public class ColumnNamer {
      * @param columnNameOverride single overriding column name
      * @return the new column name
      */
-    public static String getColumnName(Expression columnExp, int indexOfColumn, String columnNameOverride) {
+    public String getColumnName(Expression columnExp, int indexOfColumn, String columnNameOverride) {
         // try a name from the column name override
         String columnName = null;
         if (columnNameOverride != null){
@@ -90,106 +104,59 @@ public class ColumnNamer {
         }
         // go with a innocuous default name pattern
         if (columnName==null){
-            columnName =  defaultColumnNamePattern.replace("$$", ""+(indexOfColumn+1));
-       }
+            columnName =  configuration.getDefaultColumnNamePattern().replace("$$", ""+(indexOfColumn+1));
+        }
+        if(existingColumnNames.contains(columnName) && configuration.isGenerateUniqueColumnNames()){
+            columnName = generateUniqueName(columnName);
+        }
+        existingColumnNames.add(columnName);
         return columnName;
     }
         
-    public static boolean isAllowableColumnName(String proposedName){
+    private String generateUniqueName(String columnName) {
+        String newColumnName = columnName;
+        int loopCount = 2;
+        while(existingColumnNames.contains(newColumnName)){
+            
+            String loopCountString = "_"+loopCount;
+            newColumnName = columnName.substring(0,Math.min(columnName.length(), configuration.getMaxIdentiferLength()-loopCountString.length()))+loopCountString;
+            
+            loopCount++;
+        }
+        return newColumnName;
+    }
+    
+    public boolean isAllowableColumnName(String proposedName){
         
         // check null
         if (proposedName == null){
             return false;
         }
         // check size limits
-        if (proposedName.length() > maxIdentiferLength || proposedName.length()==0){
+        if (proposedName.length() > configuration.getMaxIdentiferLength() || proposedName.length()==0){
             return false;
         }
-        Matcher match = compiledRegularExpressionMatchAllowed.matcher(proposedName);
+        Matcher match = configuration.getCompiledRegularExpressionMatchAllowed().matcher(proposedName);
         if(!match.matches()){
             return false;
         }
         return true;
     }
  
-    private static String fixColumnName(String proposedName) {
-        Matcher match = compiledRegularExpressionMatchDisallowed.matcher(proposedName);
+    private String fixColumnName(String proposedName) {
+        Matcher match = configuration.getCompiledRegularExpressionMatchDisallowed().matcher(proposedName);
         proposedName = match.replaceAll("");
         
         // check size limits - then truncate
-        if (proposedName.length() > maxIdentiferLength){
-            proposedName=proposedName.substring(0, maxIdentiferLength);
+        if (proposedName.length() > configuration.getMaxIdentiferLength()){
+            proposedName=proposedName.substring(0, configuration.getMaxIdentiferLength());
         }
         
         return proposedName;
     }
     
-    private static String unquoteString(String s){
-        if(s.startsWith("'") && s.endsWith("'")){
-            s = s.substring(1, s.length()-1);
-            return s;
-        }
-        return s;
+    public ColumnNamerConfiguration getConfiguration() {
+        return configuration;
     }
     
-    
-    static int maxIdentiferLength = Integer.MAX_VALUE;
-    static String regularExpressionMatchAllowed =    "(?m)(?s).+";
-    static String regularExpressionMatchDisallowed = "(?m)(?s)[\\x00]";
-    static String defaultColumnNamePattern = "_unnamed_column_$$_";
-    
-    static Pattern compiledRegularExpressionMatchAllowed = Pattern.compile(regularExpressionMatchAllowed);
-    static Pattern compiledRegularExpressionMatchDisallowed = Pattern.compile(regularExpressionMatchDisallowed);
-    
-    public static void configure(String stringValue) {
-        try{
-            if(stringValue.equalsIgnoreCase(DEFAULT_COMMAND)){
-                maxIdentiferLength = Integer.MAX_VALUE;
-                regularExpressionMatchAllowed = "(?m)(?s).+";
-                regularExpressionMatchDisallowed = "(?m)(?s)[\\x00]";
-                defaultColumnNamePattern = "_UNNAMED_$$";
-            } else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"ORACLE128")){
-                maxIdentiferLength = 128;
-                regularExpressionMatchAllowed = "(?m)(?s)\"?[A-Za-z0-9_]+\"?";
-                regularExpressionMatchDisallowed = "(?m)(?s)[^A-Za-z0-9_\"]";
-                defaultColumnNamePattern = "_UNNAMED_$$";
-            } else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"ORACLE30")){
-                    maxIdentiferLength = 30;
-                    regularExpressionMatchAllowed = "(?m)(?s)\"?[A-Za-z0-9_]+\"?";
-                    regularExpressionMatchDisallowed = "(?m)(?s)[^A-Za-z0-9_\"]";
-                    defaultColumnNamePattern = "_UNNAMED_$$";
-            }else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"POSTGRES")){
-                maxIdentiferLength = 31;
-                regularExpressionMatchAllowed = "(?m)(?s)\"?[A-Za-z0-9_\"]+\"?";
-                regularExpressionMatchDisallowed = "(?m)(?s)[^A-Za-z0-9_\"]";
-                defaultColumnNamePattern = "_UNNAMED_$$";
-            } else if(stringValue.startsWith(MAX_IDENTIFIER_LENGTH)){
-                maxIdentiferLength = Math.max(0,Integer.parseInt(stringValue.substring(MAX_IDENTIFIER_LENGTH.length())));            
-            } else if(stringValue.startsWith(DEFAULT_COLUMN_NAME_PATTERN)){
-                defaultColumnNamePattern =unquoteString(stringValue.substring(DEFAULT_COLUMN_NAME_PATTERN.length()));            
-            } else if(stringValue.startsWith(REGULAR_EXPRESSION_MATCH_ALLOWED)){
-                regularExpressionMatchAllowed=unquoteString(stringValue.substring(REGULAR_EXPRESSION_MATCH_ALLOWED.length()));            
-            } else if(stringValue.startsWith(REGULAR_EXPRESSION_MATCH_DISALLOWED)){
-                regularExpressionMatchDisallowed =unquoteString(stringValue.substring(REGULAR_EXPRESSION_MATCH_DISALLOWED.length()));            
-            }
-            else
-            {
-                throw DbException.getInvalidValueException("SET COLUMN_NAME_RULES: unknown id:"+stringValue,
-                        stringValue);
-    
-            }
-           
-            // recompile RE patterns
-            compiledRegularExpressionMatchAllowed = Pattern.compile(regularExpressionMatchAllowed);
-            compiledRegularExpressionMatchDisallowed = Pattern.compile(regularExpressionMatchDisallowed);
-        }
-        //Including NumberFormatException|PatternSyntaxException
-        catch(RuntimeException e){
-            throw DbException.getInvalidValueException("SET COLUMN_NAME_RULES:"+e.getMessage(),
-                    stringValue);
-
-        }
-        
-    }
-
 }

h2/src/main/org/h2/util/ColumnNamerConfiguration.java

+package org.h2.util;
+
+import java.util.regex.Pattern;
+import org.h2.message.DbException;
+
+public class ColumnNamerConfiguration {
+    private static final String DEFAULT_COMMAND = "DEFAULT";
+    private static final String REGULAR_EXPRESSION_MATCH_DISALLOWED = "REGULAR_EXPRESSION_MATCH_DISALLOWED = ";
+    private static final String REGULAR_EXPRESSION_MATCH_ALLOWED = "REGULAR_EXPRESSION_MATCH_ALLOWED = ";
+    private static final String DEFAULT_COLUMN_NAME_PATTERN = "DEFAULT_COLUMN_NAME_PATTERN = ";
+    private static final String MAX_IDENTIFIER_LENGTH = "MAX_IDENTIFIER_LENGTH = ";
+    private static final String EMULATE_COMMAND = "EMULATE = ";
+    private static final String GENERATE_UNIQUE_COLUMN_NAMES = "GENERATE_UNIQUE_COLUMN_NAMES = ";
+    
+    private int maxIdentiferLength;
+    private String regularExpressionMatchAllowed;
+    private String regularExpressionMatchDisallowed;
+    private String defaultColumnNamePattern;
+    private boolean generateUniqueColumnNames;
+    private Pattern compiledRegularExpressionMatchAllowed;
+    private Pattern compiledRegularExpressionMatchDisallowed;
+
+    public ColumnNamerConfiguration(int maxIdentiferLength, String regularExpressionMatchAllowed,
+            String regularExpressionMatchDisallowed, String defaultColumnNamePattern, boolean generateUniqueColumnNames) {
+        
+        this.maxIdentiferLength = maxIdentiferLength;
+        this.regularExpressionMatchAllowed = regularExpressionMatchAllowed;
+        this.regularExpressionMatchDisallowed = regularExpressionMatchDisallowed;
+        this.defaultColumnNamePattern = defaultColumnNamePattern;
+        this.generateUniqueColumnNames = generateUniqueColumnNames;
+        
+        compiledRegularExpressionMatchAllowed = Pattern.compile(regularExpressionMatchAllowed);
+        compiledRegularExpressionMatchDisallowed = Pattern.compile(regularExpressionMatchDisallowed);
+    }
+
+    public int getMaxIdentiferLength() {
+        return maxIdentiferLength;
+    }
+
+    public void setMaxIdentiferLength(int maxIdentiferLength) {
+        this.maxIdentiferLength = maxIdentiferLength;
+    }
+
+    public String getRegularExpressionMatchAllowed() {
+        return regularExpressionMatchAllowed;
+    }
+
+    public void setRegularExpressionMatchAllowed(String regularExpressionMatchAllowed) {
+        this.regularExpressionMatchAllowed = regularExpressionMatchAllowed;
+    }
+
+    public String getRegularExpressionMatchDisallowed() {
+        return regularExpressionMatchDisallowed;
+    }
+
+    public void setRegularExpressionMatchDisallowed(String regularExpressionMatchDisallowed) {
+        this.regularExpressionMatchDisallowed = regularExpressionMatchDisallowed;
+    }
+
+    public String getDefaultColumnNamePattern() {
+        return defaultColumnNamePattern;
+    }
+
+    public void setDefaultColumnNamePattern(String defaultColumnNamePattern) {
+        this.defaultColumnNamePattern = defaultColumnNamePattern;
+    }
+
+    public Pattern getCompiledRegularExpressionMatchAllowed() {
+        return compiledRegularExpressionMatchAllowed;
+    }
+
+    public void setCompiledRegularExpressionMatchAllowed(Pattern compiledRegularExpressionMatchAllowed) {
+        this.compiledRegularExpressionMatchAllowed = compiledRegularExpressionMatchAllowed;
+    }
+
+    public Pattern getCompiledRegularExpressionMatchDisallowed() {
+        return compiledRegularExpressionMatchDisallowed;
+    }
+
+    public void setCompiledRegularExpressionMatchDisallowed(Pattern compiledRegularExpressionMatchDisallowed) {
+        this.compiledRegularExpressionMatchDisallowed = compiledRegularExpressionMatchDisallowed;
+    }
+    
+    public void configure(String stringValue) {
+        try{
+            if(stringValue.equalsIgnoreCase(DEFAULT_COMMAND)){
+                setMaxIdentiferLength(Integer.MAX_VALUE);
+                setRegularExpressionMatchAllowed("(?m)(?s).+");
+                setRegularExpressionMatchDisallowed("(?m)(?s)[\\x00]");
+                setDefaultColumnNamePattern("_UNNAMED_$$");
+            } else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"ORACLE128")){
+                setMaxIdentiferLength(128);
+                setRegularExpressionMatchAllowed("(?m)(?s)\"?[A-Za-z0-9_]+\"?");
+                setRegularExpressionMatchDisallowed("(?m)(?s)[^A-Za-z0-9_\"]");
+                setDefaultColumnNamePattern("_UNNAMED_$$");
+            } else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"ORACLE30")){
+                    setMaxIdentiferLength(30);
+                    setRegularExpressionMatchAllowed("(?m)(?s)\"?[A-Za-z0-9_]+\"?");
+                    setRegularExpressionMatchDisallowed("(?m)(?s)[^A-Za-z0-9_\"]");
+                    setDefaultColumnNamePattern("_UNNAMED_$$");
+            }else if(stringValue.equalsIgnoreCase(EMULATE_COMMAND+"POSTGRES")){
+                setMaxIdentiferLength(31);
+                setRegularExpressionMatchAllowed("(?m)(?s)\"?[A-Za-z0-9_\"]+\"?");
+                setRegularExpressionMatchDisallowed("(?m)(?s)[^A-Za-z0-9_\"]");
+                setDefaultColumnNamePattern("_UNNAMED_$$");
+            } else if(stringValue.startsWith(MAX_IDENTIFIER_LENGTH)){
+                int maxLength = Integer.parseInt(stringValue.substring(MAX_IDENTIFIER_LENGTH.length()));
+                setMaxIdentiferLength(Math.max(30,maxLength));
+                if(maxLength!=getMaxIdentiferLength()){
+                    throw DbException.getInvalidValueException("Illegal value (<30) in SET COLUMN_NAME_RULES="+stringValue,stringValue);
+                }
+            } else if(stringValue.startsWith(GENERATE_UNIQUE_COLUMN_NAMES)){
+                setGenerateUniqueColumnNames(Integer.parseInt(stringValue.substring(GENERATE_UNIQUE_COLUMN_NAMES.length()))==1);            
+            } else if(stringValue.startsWith(DEFAULT_COLUMN_NAME_PATTERN)){
+                setDefaultColumnNamePattern(unquoteString(stringValue.substring(DEFAULT_COLUMN_NAME_PATTERN.length())));            
+            } else if(stringValue.startsWith(REGULAR_EXPRESSION_MATCH_ALLOWED)){
+                setRegularExpressionMatchAllowed(unquoteString(stringValue.substring(REGULAR_EXPRESSION_MATCH_ALLOWED.length())));            
+            } else if(stringValue.startsWith(REGULAR_EXPRESSION_MATCH_DISALLOWED)){
+                setRegularExpressionMatchDisallowed(unquoteString(stringValue.substring(REGULAR_EXPRESSION_MATCH_DISALLOWED.length())));            
+            }
+            else
+            {
+                throw DbException.getInvalidValueException("SET COLUMN_NAME_RULES: unknown id:"+stringValue,
+                        stringValue);
+    
+            }
+           
+            // recompile RE patterns
+            setCompiledRegularExpressionMatchAllowed(Pattern.compile(getRegularExpressionMatchAllowed()));
+            setCompiledRegularExpressionMatchDisallowed(Pattern.compile(getRegularExpressionMatchDisallowed()));
+        }
+        //Including NumberFormatException|PatternSyntaxException
+        catch(RuntimeException e){
+            throw DbException.getInvalidValueException("SET COLUMN_NAME_RULES:"+e.getMessage(),
+                    stringValue);
+
+        }        
+    }    
+    
+    public static ColumnNamerConfiguration getDefault(){
+        return new ColumnNamerConfiguration(Integer.MAX_VALUE, "(?m)(?s).+", "(?m)(?s)[\\x00]", "_unnamed_column_$$_",false);
+    }
+    
+    private static String unquoteString(String s){
+        if(s.startsWith("'") && s.endsWith("'")){
+            s = s.substring(1, s.length()-1);
+            return s;
+        }
+        return s;
+    }
+
+    public boolean isGenerateUniqueColumnNames() {
+        return generateUniqueColumnNames;
+    }
+
+    public void setGenerateUniqueColumnNames(boolean generateUniqueColumnNames) {
+        this.generateUniqueColumnNames = generateUniqueColumnNames;
+    }
+        
+}
\ No newline at end of file

h2/src/test/org/h2/test/TestAll.java

@@ -230,6 +230,7 @@ import org.h2.test.utils.SelfDestructor;
 import org.h2.tools.DeleteDbFiles;
 import org.h2.tools.Server;
 import org.h2.util.AbbaLockingDetector;
+import org.h2.util.TestColumnNamer;
 import org.h2.util.New;
 import org.h2.util.Profiler;
 import org.h2.util.StringUtils;
@@ -782,6 +783,8 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
         addTest(new TestViewDropView());
         addTest(new TestReplace());
         addTest(new TestSynonymForTable());
+        addTest(new TestColumnNamer());
+        
 
         // jaqu
         addTest(new AliasMapTest());

h2/src/test/org/h2/test/scripts/functions/system/set.sql

@@ -4,7 +4,7 @@
 --
 -- Try a custom column naming rules setup
 
-SET COLUMN_NAME_RULES=MAX_IDENTIFIER_LENGTH = 10;
+SET COLUMN_NAME_RULES=MAX_IDENTIFIER_LENGTH = 30;
 > ok
 
 SET COLUMN_NAME_RULES=REGULAR_EXPRESSION_MATCH_ALLOWED = '[A-Za-z0-9_]+';
@@ -16,11 +16,14 @@ SET COLUMN_NAME_RULES=REGULAR_EXPRESSION_MATCH_DISALLOWED = '[^A-Za-z0-9_]+';
 SET COLUMN_NAME_RULES=DEFAULT_COLUMN_NAME_PATTERN = 'noName$$';
 > ok
 
-SELECT 1 AS VERY_VERY_VERY_LONG_ID, SUM(X)+1 AS _123456789012345, SUM(X)+1 , SUM(X)+1 
+SET COLUMN_NAME_RULES=GENERATE_UNIQUE_COLUMN_NAMES = 1;
+> ok
+
+SELECT 1 AS VERY_VERY_VERY_LONG_ID_VERY_VERY_VERY_LONG_ID, SUM(X)+1 AS _123456789012345, SUM(X)+1 , SUM(X)+1 
 +47, 'x' , '!!!' , '!!!!' FROM SYSTEM_RANGE(1,2);
-> VERY_VERY_ _123456789 SUMX1 SUMX147 x noName6 noName7
-> ---------- ---------- ----- ------- - ------- -------
-> 1          4          4     51      x !!!     !!!!
+> VERY_VERY_VERY_LONG_ID_VERY_VE _123456789012345 SUMX1 SUMX147 x noName6 noName7
+> ------------------------------ ---------------- ----- ------- - ------- -------
+> 1                              4                4     51      x !!!     !!!!
 
 SET COLUMN_NAME_RULES=EMULATE=ORACLE128;
 > ok

h2/src/test/org/h2/util/TestColumnNamer.java

+package org.h2.util;
+
+
+import org.h2.expression.Expression;
+import org.h2.expression.ValueExpression;
+import org.h2.test.TestBase;
+
+public class TestColumnNamer extends TestBase {
+        
+    private String[] ids = new String[]{
+      "ABC"
+      ,"123"
+      ,"a\n2"
+      ,"a$c%d#e@f!."
+      ,null
+      ,"VERYVERYVERYVERYVERYVERYLONGVERYVERYVERYVERYVERYVERYLONGVERYVERYVERYVERYVERYVERYLONG"
+      ,"'!!!'"
+      ,"'!!!!'"
+      ,"3.1415"
+      ,"\r"
+      ,"col1"
+      ,"col1"
+      ,"col1"
+      ,"col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2"
+      ,"col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2col2"
+    };
+    
+    private String[] expectedColumnName= {"ABC"
+            ,"123"
+            ,"a2"
+            ,"acdef"
+            ,"colName6"
+            ,"VERYVERYVERYVERYVERYVERYLONGVE"
+            ,"colName8"
+            ,"colName9"
+            ,"31415"
+            ,"colName11"
+            ,"col1"
+            ,"col1_2"
+            ,"col1_3"
+            ,"col2col2col2col2col2col2col2co"
+            ,"col2col2col2col2col2col2col2_2"};    
+    public static void main(String[] args){
+        
+        new TestColumnNamer().test();
+    }
+
+    public void test() {
+        ColumnNamer columnNamer = new ColumnNamer(null);
+        columnNamer.getConfiguration().configure("MAX_IDENTIFIER_LENGTH = 30");
+        columnNamer.getConfiguration().configure("REGULAR_EXPRESSION_MATCH_ALLOWED = '[A-Za-z0-9_]+'");
+        columnNamer.getConfiguration().configure("REGULAR_EXPRESSION_MATCH_DISALLOWED = '[^A-Za-z0-9_]+'");
+        columnNamer.getConfiguration().configure("DEFAULT_COLUMN_NAME_PATTERN = 'colName$$'");
+        columnNamer.getConfiguration().configure("GENERATE_UNIQUE_COLUMN_NAMES = 1");
+        
+        int index =0;
+        for(String id : ids){
+            Expression columnExp = ValueExpression.getDefault();
+            String newColumnName = columnNamer.getColumnName(columnExp , index+1, id);
+            assertTrue(newColumnName!=null);
+            assertTrue(newColumnName.length()<=30);
+            assertTrue(newColumnName.length()>=1);
+            assertEquals(newColumnName,expectedColumnName[index]);
+            index++;
+        }
+    }
+}