Use String#isEmpty()

stonio · snicoll · commit 7d062df9926c · 2017-02-22T11:55:17.000+01:00
Closes gh-1335
diff --git a/spring-beans/src/main/java/org/springframework/beans/PropertyMatches.java b/spring-beans/src/main/java/org/springframework/beans/PropertyMatches.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -150,10 +150,10 @@ else if (i == this.possibleMatches.length - 2) {
 	 * @return the distance value
 	 */
 	private static int calculateStringDistance(String s1, String s2) {
-		if (s1.length() == 0) {
+		if (s1.isEmpty()) {
 			return s2.length();
 		}
-		if (s2.length() == 0) {
+		if (s2.isEmpty()) {
 			return s1.length();
 		}
 		int d[][] = new int[s1.length() + 1][s2.length() + 1];
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/StringToCharacterConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/StringToCharacterConverter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,7 +28,7 @@ final class StringToCharacterConverter implements Converter<String, Character> {
 
 	@Override
 	public Character convert(String source) {
-		if (source.length() == 0) {
+		if (source.isEmpty()) {
 			return null;
 		}
 		if (source.length() > 1) {
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/StringToEnumConverterFactory.java b/spring-core/src/main/java/org/springframework/core/convert/support/StringToEnumConverterFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,7 +45,7 @@ public StringToEnum(Class<T> enumType) {
 
 		@Override
 		public T convert(String source) {
-			if (source.length() == 0) {
+			if (source.isEmpty()) {
 				// It's an empty enum identifier: reset the enum value to null.
 				return null;
 			}
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/StringToNumberConverterFactory.java b/spring-core/src/main/java/org/springframework/core/convert/support/StringToNumberConverterFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -56,7 +56,7 @@ public StringToNumber(Class<T> targetType) {
 
 		@Override
 		public T convert(String source) {
-			if (source.length() == 0) {
+			if (source.isEmpty()) {
 				return null;
 			}
 			return NumberUtils.parseNumber(source, this.targetType);
diff --git a/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java b/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -809,7 +809,7 @@ private static class PatternVirtualFileVisitor implements InvocationHandler {
 		public PatternVirtualFileVisitor(String rootPath, String subPattern, PathMatcher pathMatcher) {
 			this.subPattern = subPattern;
 			this.pathMatcher = pathMatcher;
-			this.rootPath = (rootPath.length() == 0 || rootPath.endsWith("/") ? rootPath : rootPath + "/");
+			this.rootPath = (rootPath.isEmpty() || rootPath.endsWith("/") ? rootPath : rootPath + "/");
 		}
 
 		@Override
diff --git a/spring-core/src/main/java/org/springframework/util/Base64Utils.java b/spring-core/src/main/java/org/springframework/util/Base64Utils.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -120,7 +120,7 @@ public static byte[] decodeFromString(String src) {
 		if (src == null) {
 			return null;
 		}
-		if (src.length() == 0) {
+		if (src.isEmpty()) {
 			return new byte[0];
 		}
 		return decode(src.getBytes(DEFAULT_CHARSET));
diff --git a/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java b/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java
@@ -180,7 +180,7 @@ public static MimeType parseMimeType(String mimeType) {
 
 		int index = mimeType.indexOf(';');
 		String fullType = (index >= 0 ? mimeType.substring(0, index) : mimeType).trim();
-		if (fullType.length() == 0) {
+		if (fullType.isEmpty()) {
 			throw new InvalidMimeTypeException(mimeType, "'mimeType' must not be empty");
 		}
 
diff --git a/spring-core/src/main/java/org/springframework/util/StringUtils.java b/spring-core/src/main/java/org/springframework/util/StringUtils.java
@@ -373,7 +373,7 @@ public static boolean substringMatch(CharSequence str, int index, CharSequence s
 	 * @param sub string to search for. Return 0 if this is {@code null}.
 	 */
 	public static int countOccurrencesOf(String str, String sub) {
-		if (str == null || sub == null || str.length() == 0 || sub.length() == 0) {
+		if (!hasLength(str) || !hasLength(sub)) {
 			return 0;
 		}
 		int count = 0;
@@ -515,7 +515,7 @@ public static String uncapitalize(String str) {
 	}
 
 	private static String changeFirstCharacterCase(String str, boolean capitalize) {
-		if (str == null || str.length() == 0) {
+		if (!hasLength(str)) {
 			return str;
 		}
 		else {
diff --git a/spring-core/src/main/java/org/springframework/util/xml/AbstractStaxHandler.java b/spring-core/src/main/java/org/springframework/util/xml/AbstractStaxHandler.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -223,8 +223,8 @@ protected QName toQName(String namespaceUri, String qualifiedName) {
 	protected boolean isNamespaceDeclaration(QName qName) {
 		String prefix = qName.getPrefix();
 		String localPart = qName.getLocalPart();
-		return (XMLConstants.XMLNS_ATTRIBUTE.equals(localPart) && prefix.length() == 0) ||
-				(XMLConstants.XMLNS_ATTRIBUTE.equals(prefix) && localPart.length() != 0);
+		return (XMLConstants.XMLNS_ATTRIBUTE.equals(localPart) && prefix.isEmpty()) ||
+				(XMLConstants.XMLNS_ATTRIBUTE.equals(prefix) && !localPart.isEmpty());
 	}
 
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/common/TemplateAwareExpressionParser.java b/spring-expression/src/main/java/org/springframework/expression/common/TemplateAwareExpressionParser.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -79,7 +79,7 @@ public Expression parseExpression(String expressionString, ParserContext context
 
 	private Expression parseTemplate(String expressionString, ParserContext context)
 			throws ParseException {
-		if (expressionString.length() == 0) {
+		if (expressionString.isEmpty()) {
 			return new LiteralExpression("");
 		}
 		Expression[] expressions = parseExpressions(expressionString, context);
@@ -145,7 +145,7 @@ private Expression[] parseExpressions(String expressionString, ParserContext con
 						suffixIndex);
 				expr = expr.trim();
 
-				if (expr.length() == 0) {
+				if (expr.isEmpty()) {
 					throw new ParseException(expressionString, prefixIndex,
 							"No expression defined within delimiter '" + prefix + suffix
 									+ "' at character " + prefixIndex);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java
@@ -142,7 +142,7 @@ private NamedValueInfo getNamedValueInfo(MethodParameter parameter) {
 	 */
 	private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValueInfo info) {
 		String name = info.name;
-		if (info.name.length() == 0) {
+		if (info.name.isEmpty()) {
 			name = parameter.getParameterName();
 			if (name == null) {
 				throw new IllegalArgumentException("Name for argument type [" + parameter.getParameterType().getName() +
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -160,7 +160,7 @@ private NamedValueInfo getNamedValueInfo(MethodParameter parameter) {
 	 */
 	private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValueInfo info) {
 		String name = info.name;
-		if (info.name.length() == 0) {
+		if (info.name.isEmpty()) {
 			name = parameter.getParameterName();
 			if (name == null) {
 				throw new IllegalArgumentException(
diff --git a/spring-web/src/main/java/org/springframework/web/util/patterns/PathPattern.java b/spring-web/src/main/java/org/springframework/web/util/patterns/PathPattern.java
@@ -21,6 +21,7 @@
 import java.util.Map;
 
 import org.springframework.util.PathMatcher;
+import static org.springframework.util.StringUtils.hasLength;
 
 /**
  * Represents a parsed path pattern. Includes a chain of path elements
@@ -132,9 +133,9 @@ public PathPattern(String patternText, PathElement head, char separator, boolean
 	 */
 	public boolean matches(String path) {
 		if (head == null) {
-			return (path == null) || (path.length() == 0);
+			return !hasLength(path);
 		}
-		else if (path == null || path.length() == 0) {
+		else if (!hasLength(path)) {
 			if (head instanceof WildcardTheRestPathElement || head instanceof CaptureTheRestPathElement) {
 				path = ""; // Will allow CaptureTheRest to bind the variable to empty
 			}
@@ -152,9 +153,9 @@ else if (path == null || path.length() == 0) {
 	 */
 	public boolean matchStart(String path) {
 		if (head == null) {
-			return (path == null || path.length() == 0);
+			return !hasLength(path);
 		}
-		else if (path == null || path.length() == 0) {
+		else if (!hasLength(path)) {
 			return true;
 		}
 		MatchingContext matchingContext = new MatchingContext(path, false);
@@ -172,7 +173,7 @@ public Map<String, String> matchAndExtract(String path) {
 			return matchingContext.getExtractedVariables();
 		}
 		else {
-			if (path == null || path.length() == 0) {
+			if (!hasLength(path)) {
 				return NO_VARIABLES_MAP;
 			}
 			else {
@@ -434,15 +435,15 @@ public int scanAhead(int pos) {
 	 */
 	public String combine(String pattern2string) {
 		// If one of them is empty the result is the other. If both empty the result is ""
-		if (patternString == null || patternString.length() == 0) {
-			if (pattern2string == null || pattern2string.length() == 0) {
+		if (!hasLength(patternString)) {
+			if (!hasLength(pattern2string)) {
 				return "";
 			}
 			else {
 				return pattern2string;
 			}
 		}
-		else if (pattern2string == null || pattern2string.length() == 0) {
+		else if (!hasLength(pattern2string)) {
 			return patternString;
 		}
 
@@ -504,4 +505,4 @@ else if (path1EndsWithSeparator || path2StartsWithSeparator) {
 		}
 	}
 
-}
+}
diff --git a/spring-web/src/test/java/org/springframework/web/multipart/commons/CommonsMultipartResolverTests.java b/spring-web/src/test/java/org/springframework/web/multipart/commons/CommonsMultipartResolverTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -258,13 +258,13 @@ private void doTestBinding(MockCommonsMultipartResolver resolver, MockHttpServle
 		binder.setBindEmptyMultipartFiles(false);
 		String firstBound = mtb2.getField2();
 		binder.bind(request);
-		assertTrue(mtb2.getField2().length() > 0);
+		assertFalse(mtb2.getField2().isEmpty());
 		assertEquals(firstBound, mtb2.getField2());
 
 		request = resolver.resolveMultipart(originalRequest);
 		binder.setBindEmptyMultipartFiles(true);
 		binder.bind(request);
-		assertTrue(mtb2.getField2().length() == 0);
+		assertTrue(mtb2.getField2().isEmpty());
 	}
 
 	@Test
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractNamedValueArgumentResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractNamedValueArgumentResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -132,7 +132,7 @@ private NamedValueInfo getNamedValueInfo(MethodParameter parameter) {
 	 */
 	private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValueInfo info) {
 		String name = info.name;
-		if (info.name.length() == 0) {
+		if (info.name.isEmpty()) {
 			name = parameter.getParameterName();
 			if (name == null) {
 				String type = parameter.getNestedParameterType().getName();
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -159,7 +159,7 @@ public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer m
 
 	private String getPartName(MethodParameter methodParam, RequestPart requestPart) {
 		String partName = (requestPart != null ? requestPart.name() : "");
-		if (partName.length() == 0) {
+		if (partName.isEmpty()) {
 			partName = methodParam.getParameterName();
 			if (partName == null) {
 				throw new IllegalArgumentException("Request part name for argument type [" +
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SseEmitter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SseEmitter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.util.StringUtils;
 
 /**
  * A specialization of {@link ResponseBodyEmitter} for sending
@@ -234,7 +235,7 @@ SseEventBuilderImpl append(String text) {
 
 		@Override
 		public Set<DataWithMediaType> build() {
-			if ((this.sb == null || this.sb.length() == 0) && this.dataToSend.isEmpty()) {
+			if (!StringUtils.hasLength(this.sb) && this.dataToSend.isEmpty()) {
 				return Collections.emptySet();
 			}
 			append("\n");

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,5 @@`
`1`	`1`	`/*`
`2`		`- * Copyright 2002-2016 the original author or authors.`
	`2`	`+ * Copyright 2002-2017 the original author or authors.`
`3`	`3`	`*`
`4`	`4`	`* Licensed under the Apache License, Version 2.0 (the "License");`
`5`	`5`	`* you may not use this file except in compliance with the License.`
`@@ -150,10 +150,10 @@ else if (i == this.possibleMatches.length - 2) {`
`150`	`150`	`* @return the distance value`
`151`	`151`	`*/`
`152`	`152`	`private static int calculateStringDistance(String s1, String s2) {`
`153`		`- if (s1.length() == 0) {`
	`153`	`+ if (s1.isEmpty()) {`
`154`	`154`	`return s2.length();`
`155`	`155`	`}`
`156`		`- if (s2.length() == 0) {`
	`156`	`+ if (s2.isEmpty()) {`
`157`	`157`	`return s1.length();`
`158`	`158`	`}`
`159`	`159`	`int d[][] = new int[s1.length() + 1][s2.length() + 1];`
Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,5 @@`
`1`	`1`	`/*`
`2`		`- * Copyright 2002-2012 the original author or authors.`
	`2`	`+ * Copyright 2002-2017 the original author or authors.`
`3`	`3`	`*`
`4`	`4`	`* Licensed under the Apache License, Version 2.0 (the "License");`
`5`	`5`	`* you may not use this file except in compliance with the License.`
`@@ -28,7 +28,7 @@ final class StringToCharacterConverter implements Converter<String, Character> {`
`28`	`28`
`29`	`29`	`@Override`
`30`	`30`	`public Character convert(String source) {`
`31`		`- if (source.length() == 0) {`
	`31`	`+ if (source.isEmpty()) {`
`32`	`32`	`return null;`
`33`	`33`	`}`
`34`	`34`	`if (source.length() > 1) {`
Original file line number	Diff line number	Diff line change
`@@ -180,7 +180,7 @@ public static MimeType parseMimeType(String mimeType) {`
`180`	`180`
`181`	`181`	`int index = mimeType.indexOf(';');`
`182`	`182`	`String fullType = (index >= 0 ? mimeType.substring(0, index) : mimeType).trim();`
`183`		`- if (fullType.length() == 0) {`
	`183`	`+ if (fullType.isEmpty()) {`
`184`	`184`	`throw new InvalidMimeTypeException(mimeType, "'mimeType' must not be empty");`
`185`	`185`	`}`
`186`	`186`
Original file line number	Diff line number	Diff line change
`@@ -373,7 +373,7 @@ public static boolean substringMatch(CharSequence str, int index, CharSequence s`
`373`	`373`	`* @param sub string to search for. Return 0 if this is {@code null}.`
`374`	`374`	`*/`
`375`	`375`	`public static int countOccurrencesOf(String str, String sub) {`
`376`		`- if (str == null \|\| sub == null \|\| str.length() == 0 \|\| sub.length() == 0) {`
	`376`	`+ if (!hasLength(str) \|\| !hasLength(sub)) {`
`377`	`377`	`return 0;`
`378`	`378`	`}`
`379`	`379`	`int count = 0;`
`@@ -515,7 +515,7 @@ public static String uncapitalize(String str) {`
`515`	`515`	`}`
`516`	`516`
`517`	`517`	`private static String changeFirstCharacterCase(String str, boolean capitalize) {`
`518`		`- if (str == null \|\| str.length() == 0) {`
	`518`	`+ if (!hasLength(str)) {`
`519`	`519`	`return str;`
`520`	`520`	`}`
`521`	`521`	`else {`