Add ColumnFormatter utility which can apply Column Format property for display of column values

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@1291 f203690c-595d-4dc9-a70b-905162fa7fd2

3 files changed, 91 insertions, 40 deletions

diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/expr/DefaultFunctions.java b/src/main/java/com/healthmarketscience/jackcess/impl/expr/DefaultFunctions.java
index 5a871e4..6182dd4 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/expr/DefaultFunctions.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/expr/DefaultFunctions.java
@@ -29,6 +29,7 @@ import com.healthmarketscience.jackcess.expr.EvalContext;
 import com.healthmarketscience.jackcess.expr.EvalException;
 import com.healthmarketscience.jackcess.expr.Function;
 import com.healthmarketscience.jackcess.expr.FunctionLookup;
+import com.healthmarketscience.jackcess.expr.LocaleContext;
 import com.healthmarketscience.jackcess.expr.NumericConfig;
 import com.healthmarketscience.jackcess.expr.TemporalConfig;
 import com.healthmarketscience.jackcess.expr.Value;
@@ -473,11 +474,11 @@ public class DefaultFunctions
     }
   });
 
-  private static boolean stringIsNumeric(EvalContext ctx, Value param) {
+  private static boolean stringIsNumeric(LocaleContext ctx, Value param) {
     return (maybeGetAsBigDecimal(ctx, param) != null);
   }
 
-  static BigDecimal maybeGetAsBigDecimal(EvalContext ctx, Value param) {
+  static BigDecimal maybeGetAsBigDecimal(LocaleContext ctx, Value param) {
     try {
       return param.getAsBigDecimal(ctx);
     } catch(EvalException ignored) {
@@ -490,7 +491,7 @@ public class DefaultFunctions
     return (maybeGetAsDateTimeValue(ctx, param) != null);
   }
 
-  static Value maybeGetAsDateTimeValue(EvalContext ctx, Value param) {
+  static Value maybeGetAsDateTimeValue(LocaleContext ctx, Value param) {
     try {
       // see if we can coerce to date/time
       return param.getAsDateTimeValue(ctx);
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/expr/ExpressionTokenizer.java b/src/main/java/com/healthmarketscience/jackcess/impl/expr/ExpressionTokenizer.java
index 39f7050..544c08b 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/expr/ExpressionTokenizer.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/expr/ExpressionTokenizer.java
@@ -38,6 +38,7 @@ import com.healthmarketscience.jackcess.expr.ParseException;
 import com.healthmarketscience.jackcess.expr.TemporalConfig;
 import com.healthmarketscience.jackcess.expr.Value;
 import com.healthmarketscience.jackcess.impl.ColumnImpl;
+import org.apache.commons.lang3.StringUtils;
 
 
 /**
@@ -89,7 +90,7 @@ class ExpressionTokenizer
       exprStr = exprStr.trim();
     }
 
-    if((exprStr == null) || (exprStr.length() == 0)) {
+    if(StringUtils.isEmpty(exprStr)) {
       return null;
     }
 
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/expr/FormatUtil.java b/src/main/java/com/healthmarketscience/jackcess/impl/expr/FormatUtil.java
index 14ad3fa..68fce3c 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/expr/FormatUtil.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/expr/FormatUtil.java
@@ -41,6 +41,7 @@ import com.healthmarketscience.jackcess.expr.EvalException;
 import com.healthmarketscience.jackcess.expr.NumericConfig;
 import com.healthmarketscience.jackcess.expr.TemporalConfig;
 import com.healthmarketscience.jackcess.expr.Value;
+import org.apache.commons.lang3.StringUtils;
 import static com.healthmarketscience.jackcess.impl.expr.ExpressionTokenizer.ExprBuf;
 
 /**
@@ -114,40 +115,41 @@ public class FormatUtil
   private static final Map<String,Fmt> PREDEF_FMTS = new HashMap<String,Fmt>();
 
   static {
-    PREDEF_FMTS.put("General Date", args -> ValueSupport.toValue(
+    putPredefFormat("General Date", args -> ValueSupport.toValue(
                         args.coerceToDateTimeValue().getAsString()));
-    PREDEF_FMTS.put("Long Date",
+    putPredefFormat("Long Date",
                     new PredefDateFmt(TemporalConfig.Type.LONG_DATE));
-    PREDEF_FMTS.put("Medium Date",
+    putPredefFormat("Medium Date",
                     new PredefDateFmt(TemporalConfig.Type.MEDIUM_DATE));
-    PREDEF_FMTS.put("Short Date",
+    putPredefFormat("Short Date",
                     new PredefDateFmt(TemporalConfig.Type.SHORT_DATE));
-    PREDEF_FMTS.put("Long Time",
+    putPredefFormat("Long Time",
                     new PredefDateFmt(TemporalConfig.Type.LONG_TIME));
-    PREDEF_FMTS.put("Medium Time",
+    putPredefFormat("Medium Time",
                     new PredefDateFmt(TemporalConfig.Type.MEDIUM_TIME));
-    PREDEF_FMTS.put("Short Time",
+    putPredefFormat("Short Time",
                     new PredefDateFmt(TemporalConfig.Type.SHORT_TIME));
 
-    PREDEF_FMTS.put("General Number", args -> ValueSupport.toValue(
+    putPredefFormat("General Number", args -> ValueSupport.toValue(
                         args.coerceToNumberValue().getAsString()));
-    PREDEF_FMTS.put("Currency",
+    putPredefFormat("Currency",
                     new PredefNumberFmt(NumericConfig.Type.CURRENCY));
-    PREDEF_FMTS.put("Euro", new PredefNumberFmt(NumericConfig.Type.EURO));
-    PREDEF_FMTS.put("Fixed",
+    putPredefFormat("Euro", new PredefNumberFmt(NumericConfig.Type.EURO));
+    putPredefFormat("Fixed",
                     new PredefNumberFmt(NumericConfig.Type.FIXED));
-    PREDEF_FMTS.put("Standard",
+    putPredefFormat("Standard",
                     new PredefNumberFmt(NumericConfig.Type.STANDARD));
-    PREDEF_FMTS.put("Percent",
+    putPredefFormat("Percent",
                     new PredefNumberFmt(NumericConfig.Type.PERCENT));
-    PREDEF_FMTS.put("Scientific", new ScientificPredefNumberFmt());
+    putPredefFormat("Scientific", new ScientificPredefNumberFmt());
 
-    PREDEF_FMTS.put("True/False", new PredefBoolFmt("True", "False"));
-    PREDEF_FMTS.put("Yes/No", new PredefBoolFmt("Yes", "No"));
-    PREDEF_FMTS.put("On/Off", new PredefBoolFmt("On", "Off"));
+    putPredefFormat("True/False", new PredefBoolFmt("True", "False"));
+    putPredefFormat("Yes/No", new PredefBoolFmt("Yes", "No"));
+    putPredefFormat("On/Off", new PredefBoolFmt("On", "Off"));
   }
 
   private static final Fmt NULL_FMT = args -> ValueSupport.EMPTY_STR_VAL;
+  private static final Fmt DUMMY_FMT = args -> args.getNonNullExpr();
 
   private static final char QUOTE_CHAR = '"';
   private static final char ESCAPE_CHAR = '\\';
@@ -282,6 +284,15 @@ public class FormatUtil
       _firstWeekType = firstWeekType;
     }
 
+    public Args setExpr(Value expr) {
+      _expr = expr;
+      return this;
+    }
+
+    public Value getNonNullExpr() {
+      return (_expr.isNull() ? ValueSupport.EMPTY_STR_VAL : _expr);
+    }
+
     public boolean isNullOrEmptyString() {
       return(_expr.isNull() ||
              // only a string value could ever be an empty string
@@ -385,37 +396,67 @@ public class FormatUtil
     public String getAsString() {
       return _expr.getAsString(_ctx);
     }
+
+    public Value format(Fmt fmt) {
+      Value origExpr = _expr;
+      try {
+        return fmt.format(this);
+      } catch(EvalException ee) {
+        // values which cannot be formatted as the target type are just
+        // returned "as is"
+        return origExpr;
+      }
+    }
   }
 
   private FormatUtil() {}
 
+  /**
+   * Utility for leveraging format support outside of expression evaluation.
+   */
+  public static class StandaloneFormatter
+  {
+    private final Fmt _fmt;
+    private final Args _args;
+
+    private StandaloneFormatter(Fmt fmt, Args args) {
+      _fmt = fmt;
+      _args = args;
+    }
+
+    public Value format(Value expr) {
+      return _args.setExpr(expr).format(_fmt);
+    }
+  }
 
   public static Value format(EvalContext ctx, Value expr, String fmtStr,
                              int firstDay, int firstWeekType) {
+    Args args = new Args(ctx, expr, firstDay, firstWeekType);
+    return args.format(createFormat(args, fmtStr));
+  }
 
-    try {
-      Args args = new Args(ctx, expr, firstDay, firstWeekType);
+  public static StandaloneFormatter createStandaloneFormatter(
+      EvalContext ctx, String fmtStr, int firstDay, int firstWeekType) {
+    Args args = new Args(ctx, null, firstDay, firstWeekType);
+    Fmt fmt = createFormat(args, fmtStr);
+    return new StandaloneFormatter(fmt, args);
+  }
 
-      Fmt predefFmt = PREDEF_FMTS.get(fmtStr);
-      if(predefFmt != null) {
-        if(args.isNullOrEmptyString()) {
-          // predefined formats return empty string for null
-          return ValueSupport.EMPTY_STR_VAL;
-        }
-        return predefFmt.format(args);
-      }
+  private static Fmt createFormat(Args args, String fmtStr) {
+    Fmt predefFmt = PREDEF_FMTS.get(fmtStr);
+    if(predefFmt != null) {
+      return predefFmt;
+    }
 
-      // TODO implement caching for custom formats?  put into Bindings.  use
-      // special "cache" prefix to know which caches to clear when evalconfig
-      // is altered (could also cache other Format* functions)
+    if(StringUtils.isEmpty(fmtStr)) {
+      return DUMMY_FMT;
+    }
 
-      return parseCustomFormat(fmtStr, args).format(args);
+    // TODO implement caching for custom formats?  put into Bindings.  use
+    // special "cache" prefix to know which caches to clear when evalconfig
+    // is altered (could also cache other Format* functions)
 
-    } catch(EvalException ee) {
-      // values which cannot be formatted as the target type are just
-      // returned "as is"
-      return expr;
-    }
+    return parseCustomFormat(fmtStr, args);
   }
 
   private static Fmt parseCustomFormat(String fmtStr, Args args) {
@@ -1178,6 +1219,14 @@ public class FormatUtil
     }
   }
 
+  private static void putPredefFormat(String key, Fmt fmt) {
+    // predefined formats return empty string for null
+    Fmt wrapFmt = args -> (args.isNullOrEmptyString() ?
+                           ValueSupport.EMPTY_STR_VAL :
+                           fmt.format(args));
+    PREDEF_FMTS.put(key, wrapFmt);
+  }
+
   private static final class PredefDateFmt implements Fmt
   {
     private final TemporalConfig.Type _type;