[github-339] Add extra methods to StringUtil and refactor some code to use them. Thanks to XenoAmess. This closes #339

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1902789 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 87 insertions, 12 deletions

diff --git a/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java b/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
index 23b2936af3..9dec8e6ca6 100644
--- a/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
+++ b/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
@@ -658,7 +658,7 @@ public class VBAMacroReader implements Closeable {
             } catch (EOFException e) {
                 return;
             }
-            if (mbcs.trim().length() > 0 && unicode.trim().length() > 0) {
+            if (StringUtil.isNotBlank(mbcs) && StringUtil.isNotBlank(unicode)) {
                 moduleNames.put(mbcs, unicode);
             }
 
diff --git a/poi/src/main/java/org/apache/poi/sl/draw/DrawTextParagraph.java b/poi/src/main/java/org/apache/poi/sl/draw/DrawTextParagraph.java
index 4671ce34ba..ac29af9e4e 100644
--- a/poi/src/main/java/org/apache/poi/sl/draw/DrawTextParagraph.java
+++ b/poi/src/main/java/org/apache/poi/sl/draw/DrawTextParagraph.java
@@ -63,6 +63,7 @@ import org.apache.poi.sl.usermodel.TextShape;
 import org.apache.poi.sl.usermodel.TextShape.TextDirection;
 import org.apache.poi.util.Internal;
 import org.apache.poi.util.LocaleUtil;
+import org.apache.poi.util.StringUtil;
 import org.apache.poi.util.Units;
 
 public class DrawTextParagraph implements Drawable {
@@ -242,7 +243,7 @@ public class DrawTextParagraph implements Drawable {
     }
 
     public boolean isEmptyParagraph() {
-        return (lines.isEmpty() || rawText.trim().isEmpty());
+        return (lines.isEmpty() || StringUtil.isBlank(rawText));
     }
 
     @Override
diff --git a/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java b/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
index c49d5f0e3c..dcd98bb1dc 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
@@ -42,6 +42,7 @@ import org.apache.poi.ss.util.CellRangeAddressBase;
 import org.apache.poi.ss.util.CellRangeAddressList;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.ss.util.SheetUtil;
+import org.apache.poi.util.StringUtil;
 
 /**
  * Evaluates Data Validation constraints.<p>
@@ -418,7 +419,7 @@ public class DataValidationEvaluator {
          * @throws NumberFormatException if the formula is non-numeric when it should be
          */
         private Double evalOrConstant(String formula, DataValidationContext context) throws NumberFormatException {
-            if (formula == null || formula.trim().isEmpty()) return null; // shouldn't happen, but just in case
+            if (StringUtil.isBlank(formula)) return null; // shouldn't happen, but just in case
             try {
                 return Double.valueOf(formula);
             } catch (NumberFormatException e) {
@@ -433,7 +434,7 @@ public class DataValidationEvaluator {
             if (eval instanceof NumberEval) return Double.valueOf(((NumberEval) eval).getNumberValue());
             if (eval instanceof StringEval) {
                 final String value = ((StringEval) eval).getStringValue();
-                if (value == null || value.trim().isEmpty()) return null; 
+                if (StringUtil.isBlank(value)) return null;
                 // try to parse the cell value as a double and return it 
                 return Double.valueOf(value);
             }
diff --git a/poi/src/main/java/org/apache/poi/ss/formula/EvaluationConditionalFormatRule.java b/poi/src/main/java/org/apache/poi/ss/formula/EvaluationConditionalFormatRule.java
index b3fb95f593..54199cbfca 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/EvaluationConditionalFormatRule.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/EvaluationConditionalFormatRule.java
@@ -52,6 +52,7 @@ import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.util.LocaleUtil;
+import org.apache.poi.util.StringUtil;
 
 /**
  * Abstracted and cached version of a Conditional Format rule for use with a
@@ -506,7 +507,7 @@ public class EvaluationConditionalFormatRule implements Comparable<EvaluationCon
             try {
                 String v = cv.getString();
                 // see TextFunction.TRIM for implementation
-                return v == null || v.trim().length() == 0;
+                return StringUtil.isBlank(v);
             } catch (Exception e) {
                 // not a valid string value, and not a blank cell (that's checked earlier)
                 return false;
@@ -515,7 +516,7 @@ public class EvaluationConditionalFormatRule implements Comparable<EvaluationCon
             try {
                 String v = cv.getString();
                 // see TextFunction.TRIM for implementation
-                return v != null && v.trim().length() > 0;
+                return StringUtil.isNotBlank(v);
             } catch (Exception e) {
                 // not a valid string value, but not blank
                 return true;
diff --git a/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java b/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
index f362828819..61993d676b 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
@@ -80,6 +80,7 @@ import org.apache.poi.ss.util.AreaReference;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.ss.util.CellReference.NameType;
 import org.apache.poi.util.Internal;
+import org.apache.poi.util.StringUtil;
 
 /**
  * This class parses a formula string into a List of tokens in RPN order.
@@ -255,7 +256,7 @@ public final class FormulaParser {
     private RuntimeException expected(String s) {
         String msg;
 
-        if (look == '=' && _formulaString.substring(0, _pointer-1).trim().length() < 1) {
+        if (look == '=' && StringUtil.isBlank(_formulaString.substring(0, _pointer-1))) {
             msg = "The specified formula '" + _formulaString
                 + "' starts with an equals sign which is not allowed.";
         } else {
diff --git a/poi/src/main/java/org/apache/poi/ss/formula/atp/TextJoinFunction.java b/poi/src/main/java/org/apache/poi/ss/formula/atp/TextJoinFunction.java
index 52fcb05cc0..5e7ffe8b87 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/atp/TextJoinFunction.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/atp/TextJoinFunction.java
@@ -29,7 +29,7 @@ import java.util.List;
  * Implementation of Excel function TEXTJOIN()
  *
  * <b>Syntax</b><br>
- * <b>TEXTJOIN</b>(<b>delimiter</b>, <b>ignore_empty</b>, <b>text1</b>, <b>[text2]<b>, …)<p>
+ * <b>TEXTJOIN</b>(<b>delimiter</b>, <b>ignore_empty</b>, <b>text1</b>, <b>[text2]<b>, ...)<p>
  *
  * <b>delimiter</b> A text string, either empty, or one or more characters enclosed by double quotes, or a reference to a valid text string.
  * If a number is supplied, it will be treated as text.<br>
diff --git a/poi/src/main/java/org/apache/poi/ss/usermodel/DataFormatter.java b/poi/src/main/java/org/apache/poi/ss/usermodel/DataFormatter.java
index 89c55ad4f7..6b16d7e79b 100644
--- a/poi/src/main/java/org/apache/poi/ss/usermodel/DataFormatter.java
+++ b/poi/src/main/java/org/apache/poi/ss/usermodel/DataFormatter.java
@@ -48,6 +48,7 @@ import org.apache.poi.ss.formula.ConditionalFormattingEvaluator;
 import org.apache.poi.ss.util.DateFormatConverter;
 import org.apache.poi.ss.util.NumberToTextConverter;
 import org.apache.poi.util.LocaleUtil;
+import org.apache.poi.util.StringUtil;
 
 
 /**
@@ -355,7 +356,7 @@ public class DataFormatter {
 
         int formatIndex = numFmt.getIdx();
         String formatStr = numFmt.getFormat();
-        if(formatStr == null || formatStr.trim().length() == 0) {
+        if(StringUtil.isBlank(formatStr)) {
             return null;
         }
         return getFormat(cell.getNumericCellValue(), formatIndex, formatStr, isDate1904(cell));
@@ -483,7 +484,7 @@ public class DataFormatter {
         }
 
         // Check for special cases
-        if(formatStr == null || formatStr.trim().isEmpty()) {
+        if(StringUtil.isBlank(formatStr)) {
             return getDefaultFormat(cellValue);
         }
 
@@ -1361,10 +1362,10 @@ public class DataFormatter {
             seg2 = result.substring(Math.max(0, len - 7), len - 4);
             seg1 = result.substring(Math.max(0, len - 10), Math.max(0, len - 7));
 
-            if(seg1.trim().length() > 0) {
+            if(StringUtil.isNotBlank(seg1)) {
                 sb.append('(').append(seg1).append(") ");
             }
-            if(seg2.trim().length() > 0) {
+            if(StringUtil.isNotBlank(seg2)) {
                 sb.append(seg2).append('-');
             }
             sb.append(seg3);
diff --git a/poi/src/main/java/org/apache/poi/util/StringUtil.java b/poi/src/main/java/org/apache/poi/util/StringUtil.java
index fb9d61b43d..e0ac29b4cd 100644
--- a/poi/src/main/java/org/apache/poi/util/StringUtil.java
+++ b/poi/src/main/java/org/apache/poi/util/StringUtil.java
@@ -689,4 +689,74 @@ public final class StringUtil {
         return prefix + ((newLen == 0) ? "" : new String(string, newOffset, newLen * 2, UTF16LE));
     }
 
+
+    /**
+     * Gets a CharSequence length or {@code 0} if the CharSequence is
+     * {@code null}.
+     *
+     * copied from commons-lang3
+     *
+     * @param cs
+     *            a CharSequence or {@code null}
+     * @return CharSequence length or {@code 0} if the CharSequence is
+     *         {@code null}.
+     */
+    public static int length(final CharSequence cs) {
+        return cs == null ? 0 : cs.length();
+    }
+
+    /**
+     * <p>Checks if a CharSequence is empty (""), null or whitespace only.</p>
+     *
+     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
+     *
+     * <pre>
+     * StringUtil.isBlank(null)      = true
+     * StringUtil.isBlank("")        = true
+     * StringUtil.isBlank(" ")       = true
+     * StringUtil.isBlank("bob")     = false
+     * StringUtil.isBlank("  bob  ") = false
+     * </pre>
+     *
+     * copied from commons-lang3
+     *
+     * @param cs  the CharSequence to check, may be null
+     * @return {@code true} if the CharSequence is null, empty or whitespace only
+     */
+    public static boolean isBlank(final CharSequence cs) {
+        final int strLen = length(cs);
+        if (strLen == 0) {
+            return true;
+        }
+        for (int i = 0; i < strLen; i++) {
+            if (!Character.isWhitespace(cs.charAt(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * <p>Checks if a CharSequence is not empty (""), not null and not whitespace only.</p>
+     *
+     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
+     *
+     * <pre>
+     * StringUtil.isNotBlank(null)      = false
+     * StringUtil.isNotBlank("")        = false
+     * StringUtil.isNotBlank(" ")       = false
+     * StringUtil.isNotBlank("bob")     = true
+     * StringUtil.isNotBlank("  bob  ") = true
+     * </pre>
+     *
+     * copied from commons-lang3
+     *
+     * @param cs  the CharSequence to check, may be null
+     * @return {@code true} if the CharSequence is
+     *  not empty and not null and not whitespace only
+     */
+    public static boolean isNotBlank(final CharSequence cs) {
+        return !isBlank(cs);
+    }
+
 }