replace "".equals(string) with string.isEmpty() to avoid null strings silently evaluating to false; most code should probably check string for null if it is not already

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1812476 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/hpsf/Variant.java

@@ -420,7 +420,7 @@ public class Variant
         }
         
         name += numberToName.get(vt);
-        return !"".equals(name) ? name : "unknown variant type";
+        return !name.isEmpty() ? name : "unknown variant type";
     }
 
     /**

src/java/org/apache/poi/poifs/crypt/CryptoFunctions.java

@@ -379,7 +379,7 @@ public class CryptoFunctions {
         // SET Verifier TO 0x0000
         short verifier = 0;
 
-        if (!"".equals(password)) {
+        if (!password.isEmpty()) {
             // FOR EACH PasswordByte IN PasswordArray IN REVERSE ORDER
             for (int i = arrByteChars.length-1; i >= 0; i--) {
                 // SET Verifier TO Intermediate3 BITWISE XOR PasswordByte
@@ -418,7 +418,7 @@ public class CryptoFunctions {
         //Maximum length of the password is 15 chars.
         final int maxPasswordLength = 15; 
         
-        if (!"".equals(password)) {
+        if (!password.isEmpty()) {
             // Truncate the password to 15 characters
             password = password.substring(0, Math.min(password.length(), maxPasswordLength));
 

src/java/org/apache/poi/poifs/crypt/DataSpaceMapUtils.java

@@ -356,7 +356,7 @@ public class DataSpaceMapUtils {
     }
     
     public static void writeUtf8LPP4(LittleEndianOutput os, String str) {
-        if (str == null || "".equals(str)) {
+        if (str == null || str.isEmpty()) {
             os.writeInt(str == null ? 0 : 4);
             os.writeInt(0);
         } else {

src/java/org/apache/poi/sl/draw/DrawTextParagraph.java

@@ -257,7 +257,7 @@ public class DrawTextParagraph implements Drawable {
         fact.fixFonts(graphics);
         StringBuilder text = new StringBuilder();
         AttributedString at = getAttributedString(graphics, text);
-        boolean emptyParagraph = ("".equals(text.toString().trim()));
+        boolean emptyParagraph = text.toString().trim().isEmpty();
 
         AttributedCharacterIterator it = at.getIterator();
         LineBreakMeasurer measurer = new LineBreakMeasurer(it, graphics.getFontRenderContext());

src/java/org/apache/poi/ss/formula/functions/Countblank.java

@@ -54,7 +54,7 @@ public final class Countblank extends Fixed1ArgFunction {
 			return valueEval == BlankEval.instance ||
 					// see https://support.office.com/en-us/article/COUNTBLANK-function-6a92d772-675c-4bee-b346-24af6bd3ac22
 					// "Cells with formulas that return "" (empty text) are also counted."
-					(valueEval instanceof StringEval && "".equals(((StringEval)valueEval).getStringValue()));
+					(valueEval instanceof StringEval && ((StringEval)valueEval).getStringValue().isEmpty());
 		}
 	};
 }

src/java/org/apache/poi/ss/usermodel/FractionFormat.java

@@ -150,7 +150,7 @@ public class FractionFormat extends Format {
         }
         
         //if whole part has to go into the numerator
-        if ("".equals(wholePartFormatString)){
+        if (wholePartFormatString.isEmpty()){
             int trueNum = (fract.getDenominator()*(int)wholePart)+fract.getNumerator();
             sb.append(trueNum).append("/").append(fract.getDenominator());
             return sb.toString();

src/java/org/apache/poi/util/StringUtil.java

@@ -348,7 +348,7 @@ public class StringUtil {
     * @see <a href="http://www.alanwood.net/demos/symbol.html">Symbol font - Unicode alternatives for Greek and special characters in HTML</a>
     */
    public static String mapMsCodepointString(String string) {
-       if (string == null || "".equals(string)) return string;
+       if (string == null || string.isEmpty()) return string;
        initMsCodepointMap();
        
        StringBuilder sb = new StringBuilder();

src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java

@@ -242,7 +242,7 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 	 */
 	public static OPCPackage open(String path, PackageAccess access)
 			throws InvalidFormatException, InvalidOperationException {
-		if (path == null || "".equals(path.trim())) {
+		if (path == null || path.trim().isEmpty()) {
 			throw new IllegalArgumentException("'path' must be given");
 		}
 		
@@ -459,7 +459,7 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 		try {
 			l.writeLock().lock();
 			if (this.originalPackagePath != null
-					&& !"".equals(this.originalPackagePath.trim())) {
+					&& !this.originalPackagePath.trim().isEmpty()) {
 				File targetFile = new File(this.originalPackagePath);
 				if (!targetFile.exists()
 						|| !(this.originalPackagePath

src/ooxml/java/org/apache/poi/openxml4j/opc/PackagePartName.java

@@ -260,7 +260,7 @@ public final class PackagePartName implements Comparable<PackagePartName> {
 								+ partUri.getPath());
 			}
 
-			if ("".equals(seg.replaceAll("\\\\.", ""))) {
+			if (seg.replaceAll("\\\\.", "").isEmpty()) {
 				// Normally will never been invoked with the previous
 				// implementation rule [M1.9]
 				throw new InvalidFormatException(

src/ooxml/java/org/apache/poi/openxml4j/opc/ZipPackage.java

@@ -430,7 +430,7 @@ public final class ZipPackage extends OPCPackage {
         // Flush the package
         flush();
 
-		if (this.originalPackagePath == null || "".equals(this.originalPackagePath)) {
+		if (this.originalPackagePath == null || this.originalPackagePath.isEmpty()) {
 		    return;
 		}
 

src/ooxml/java/org/apache/poi/poifs/crypt/dsig/OOXMLURIDereferencer.java

@@ -112,7 +112,7 @@ public class OOXMLURIDereferencer implements URIDereferencer, SignatureConfigura
         LOG.log(POILogger.DEBUG, "dereference", uri);
 
         String path = uri.getPath();
-        if (path == null || "".equals(path)) {
+        if (path == null || path.isEmpty()) {
             LOG.log(POILogger.DEBUG, "illegal part name (expected)", uri);
             return null;
         }

src/ooxml/java/org/apache/poi/poifs/crypt/dsig/services/RelationshipTransformService.java

@@ -205,7 +205,7 @@ public class RelationshipTransformService extends TransformService {
                 String id = el.getAttribute("Id");
                 if (sourceIds.contains(id)) {
                     String targetMode = el.getAttribute("TargetMode");
-                    if ("".equals(targetMode)) {
+                    if (targetMode.isEmpty()) {
                         el.setAttribute("TargetMode", "Internal");
                     }
                     rsList.put(id, el);

src/ooxml/java/org/apache/poi/ss/extractor/EmbeddedExtractor.java

@@ -138,14 +138,14 @@ public class EmbeddedExtractor implements Iterable<EmbeddedExtractor> {
             String extension = (filename == null || filename.lastIndexOf('.') == -1) ? ".bin" : filename.substring(filename.lastIndexOf('.'));
             
             // try to find an alternative name
-            if (filename == null || "".equals(filename) || filename.startsWith("MBD") || filename.startsWith("Root Entry")) {
+            if (filename == null || filename.isEmpty() || filename.startsWith("MBD") || filename.startsWith("Root Entry")) {
                 filename = shape.getShapeName();
                 if (filename != null) {
                     filename += extension;
                 }
             }
             // default to dummy name
-            if (filename == null || "".equals(filename)) {
+            if (filename == null || filename.isEmpty()) {
                 filename = "picture_" + embeddings.size() + extension;
             }
             filename = filename.trim();

src/ooxml/java/org/apache/poi/xslf/usermodel/XSLFHyperlink.java

@@ -51,7 +51,7 @@ public class XSLFHyperlink implements Hyperlink<XSLFShape,XSLFTextParagraph> {
     @Override
     public String getAddress() {
         String id = _link.getId();
-        if (id == null || "".equals(id)) {
+        if (id == null || id.isEmpty()) {
             return _link.getAction();
         }
 
@@ -163,4 +163,4 @@ public class XSLFHyperlink implements Hyperlink<XSLFShape,XSLFTextParagraph> {
         _link.setId("");
         _link.setAction("ppaction://hlinkshowjump?jump="+jump);
     }
-}
+}

src/ooxml/java/org/apache/poi/xslf/usermodel/XSLFTextRun.java

@@ -845,7 +845,7 @@ public class XSLFTextRun implements TextRun {
                 }
                 // SYMBOL is missing
                 
-                if (font == null || !font.isSetTypeface() || "".equals(font.getTypeface())) {
+                if (font == null || !font.isSetTypeface() || font.getTypeface().isEmpty()) {
                     font = coll.getLatin();
                 }
             }

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFPivotTable.java

@@ -312,7 +312,7 @@ public class XSSFPivotTable extends POIXMLDocumentPart {
 
         pivotField.setAxis(STAxis.AXIS_COL);
         pivotField.setShowAll(false);
-        if (valueFormat != null && !"".equals(valueFormat.trim())) {
+        if (valueFormat != null && !valueFormat.trim().isEmpty()) {
             DataFormat df = parentSheet.getWorkbook().createDataFormat();
             pivotField.setNumFmtId(df.getFormat(valueFormat));
         }
@@ -440,7 +440,7 @@ public class XSSFPivotTable extends POIXMLDocumentPart {
         cell.setCellType(CellType.STRING);
         dataField.setName(valueFieldName);
         dataField.setFld(columnIndex);
-        if (valueFormat != null && !"".equals(valueFormat.trim())) {
+        if (valueFormat != null && !valueFormat.trim().isEmpty()) {
             DataFormat df = parentSheet.getWorkbook().createDataFormat();
             dataField.setNumFmtId(df.getFormat(valueFormat));
         }

src/ooxml/java/org/apache/poi/xssf/usermodel/helpers/XSSFPasswordHelper.java

@@ -127,7 +127,7 @@ public final class XSSFPasswordHelper {
     
     
     private static QName getAttrName(String prefix, String name) {
-        if (prefix == null || "".equals(prefix)) {
+        if (prefix == null || prefix.isEmpty()) {
             return new QName(name);
         } else {
             return new QName(prefix+Character.toUpperCase(name.charAt(0))+name.substring(1));

src/scratchpad/src/org/apache/poi/hslf/extractor/PowerPointExtractor.java

@@ -230,7 +230,7 @@ public final class PowerPointExtractor extends POIOLE2TextExtractor {
                         if(sh instanceof HSLFTextShape){
                             HSLFTextShape hsh = (HSLFTextShape)sh;
                             final String text = hsh.getText();
-                            if (text == null || "".equals(text) || "*".equals(text)) {
+                            if (text == null || text.isEmpty() || "*".equals(text)) {
                                 continue;
                             }
                             

src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFFontInfo.java

@@ -125,7 +125,7 @@ public class HSLFFontInfo implements FontInfo {
 
     @Override
     public void setTypeface(String typeface){
-        if (typeface == null || "".equals(typeface)) {
+        if (typeface == null || typeface.isEmpty()) {
             throw new IllegalArgumentException("typeface can't be null nor empty");
         }
         this.typeface = typeface;

src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFSimpleShape.java

@@ -323,7 +323,7 @@ public abstract class HSLFSimpleShape extends HSLFShape implements SimpleShape<H
         }
 
         name = name.replace("adj", "");
-        if ("".equals(name)) {
+        if (name.isEmpty()) {
             name = "1";
         }
 
@@ -727,4 +727,4 @@ public abstract class HSLFSimpleShape extends HSLFShape implements SimpleShape<H
     protected void setHyperlink(HSLFHyperlink link) {
         _hyperlink = link;
     }
-}
+}