Prefer isEmpty() over size() == 0 or length() == 0

trustin · trustin · commit bbcb03524642 · 2012-11-10T01:24:04.000+09:00
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/DefaultCookie.java b/codec-http/src/main/java/io/netty/handler/codec/http/DefaultCookie.java
@@ -48,7 +48,7 @@ public DefaultCookie(String name, String value) {
             throw new NullPointerException("name");
         }
         name = name.trim();
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("empty name");
         }
 
@@ -343,7 +343,7 @@ private static String validateValue(String name, String value) {
             return null;
         }
         value = value.trim();
-        if (value.length() == 0) {
+        if (value.isEmpty()) {
             return null;
         }
         for (int i = 0; i < value.length(); i ++) {
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpMessageDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpMessageDecoder.java
@@ -537,7 +537,7 @@ private State readHeaders(ByteBuf buffer) throws TooLongFrameException {
         String line = readHeader(buffer);
         String name = null;
         String value = null;
-        if (line.length() != 0) {
+        if (line.isEmpty()) {
             message.clearHeaders();
             do {
                 char firstChar = line.charAt(0);
@@ -553,7 +553,7 @@ private State readHeaders(ByteBuf buffer) throws TooLongFrameException {
                 }
 
                 line = readHeader(buffer);
-            } while (line.length() != 0);
+            } while (!line.isEmpty());
 
             // Add the last header.
             if (name != null) {
@@ -581,13 +581,13 @@ private HttpChunkTrailer readTrailingHeaders(ByteBuf buffer) throws TooLongFrame
         headerSize = 0;
         String line = readHeader(buffer);
         String lastHeader = null;
-        if (line.length() != 0) {
+        if (!line.isEmpty()) {
             HttpChunkTrailer trailer = new DefaultHttpChunkTrailer();
             do {
                 char firstChar = line.charAt(0);
                 if (lastHeader != null && (firstChar == ' ' || firstChar == '\t')) {
                     List<String> current = trailer.getHeaders(lastHeader);
-                    if (current.size() != 0) {
+                    if (!current.isEmpty()) {
                         int lastPos = current.size() - 1;
                         String newString = current.get(lastPos) + line.trim();
                         current.set(lastPos, newString);
@@ -606,7 +606,7 @@ private HttpChunkTrailer readTrailingHeaders(ByteBuf buffer) throws TooLongFrame
                 }
 
                 line = readHeader(buffer);
-            } while (line.length() != 0);
+            } while (!line.isEmpty());
 
             return trailer;
         }
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpMethod.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpMethod.java
@@ -110,7 +110,7 @@ public static HttpMethod valueOf(String name) {
         }
 
         name = name.trim();
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("empty name");
         }
 
@@ -137,7 +137,7 @@ public HttpMethod(String name) {
         }
 
         name = name.trim();
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("empty name");
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpVersion.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpVersion.java
@@ -85,7 +85,7 @@ public HttpVersion(String text, boolean keepAliveDefault) {
         }
 
         text = text.trim().toUpperCase();
-        if (text.length() == 0) {
+        if (text.isEmpty()) {
             throw new IllegalArgumentException("empty text");
         }
 
@@ -120,7 +120,7 @@ public HttpVersion(
         }
 
         protocolName = protocolName.trim().toUpperCase();
-        if (protocolName.length() == 0) {
+        if (protocolName.isEmpty()) {
             throw new IllegalArgumentException("empty protocolName");
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractHttpData.java b/codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractHttpData.java
@@ -15,10 +15,10 @@
  */
 package io.netty.handler.codec.http.multipart;
 
-import java.nio.charset.Charset;
-
 import io.netty.handler.codec.http.HttpConstants;
 
+import java.nio.charset.Charset;
+
 /**
  * Abstract HttpData implementation
  */
@@ -35,7 +35,7 @@ public AbstractHttpData(String name, Charset charset, long size) {
             throw new NullPointerException("name");
         }
         name = name.trim();
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("empty name");
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestDecoder.java
@@ -379,7 +379,7 @@ public boolean hasNext() throws EndOfDataDecoderException {
                 throw new EndOfDataDecoderException();
             }
         }
-        return bodyListHttpData.size() > 0 && bodyListHttpDataRank < bodyListHttpData.size();
+        return !bodyListHttpData.isEmpty() && bodyListHttpDataRank < bodyListHttpData.size();
     }
 
     /**
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoder.java
@@ -442,7 +442,7 @@ public void addBodyHttpData(InterfaceHttpData data) throws ErrorDataEncoderExcep
                 duringMixedMode = false;
             }
             InternalAttribute internal = new InternalAttribute();
-            if (multipartHttpDatas.size() > 0) {
+            if (!multipartHttpDatas.isEmpty()) {
                 // previously a data field so CRLF
                 internal.addValue("\r\n");
             }
@@ -465,7 +465,7 @@ public void addBodyHttpData(InterfaceHttpData data) throws ErrorDataEncoderExcep
         } else if (data instanceof FileUpload) {
             FileUpload fileUpload = (FileUpload) data;
             InternalAttribute internal = new InternalAttribute();
-            if (multipartHttpDatas.size() > 0) {
+            if (!multipartHttpDatas.isEmpty()) {
                 // previously a data field so CRLF
                 internal.addValue("\r\n");
             }
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker00.java b/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker00.java
@@ -133,7 +133,7 @@ public ChannelFuture handshake(Channel channel) {
         // Get path
         URI wsURL = getWebSocketUrl();
         String path = wsURL.getPath();
-        if (wsURL.getQuery() != null && wsURL.getQuery().length() > 0) {
+        if (wsURL.getQuery() != null && !wsURL.getQuery().isEmpty()) {
             path = wsURL.getPath() + "?" + wsURL.getQuery();
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker08.java b/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker08.java
@@ -101,7 +101,7 @@ public ChannelFuture handshake(Channel channel) {
         // Get path
         URI wsURL = getWebSocketUrl();
         String path = wsURL.getPath();
-        if (wsURL.getQuery() != null && wsURL.getQuery().length() > 0) {
+        if (wsURL.getQuery() != null && !wsURL.getQuery().isEmpty()) {
             path = wsURL.getPath() + "?" + wsURL.getQuery();
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker13.java b/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientHandshaker13.java
@@ -101,7 +101,7 @@ public ChannelFuture handshake(Channel channel) {
         // Get path
         URI wsURL = getWebSocketUrl();
         String path = wsURL.getPath();
-        if (wsURL.getQuery() != null && wsURL.getQuery().length() > 0) {
+        if (wsURL.getQuery() != null && !wsURL.getQuery().isEmpty()) {
             path = wsURL.getPath() + "?" + wsURL.getQuery();
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/rtsp/RtspMethods.java b/codec-http/src/main/java/io/netty/handler/codec/rtsp/RtspMethods.java
@@ -123,7 +123,7 @@ public static HttpMethod valueOf(String name) {
         }
 
         name = name.trim().toUpperCase();
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("empty name");
         }
 
diff --git a/codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyCodecUtil.java b/codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyCodecUtil.java
@@ -319,7 +319,7 @@ static void validateHeaderName(String name) {
         if (name == null) {
             throw new NullPointerException("name");
         }
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException(
                     "name cannot be length zero");
         }
@@ -349,7 +349,7 @@ static void validateHeaderValue(String value) {
         if (value == null) {
             throw new NullPointerException("value");
         }
-        if (value.length() == 0) {
+        if (value.isEmpty()) {
             throw new IllegalArgumentException(
                     "value cannot be length zero");
         }
diff --git a/common/src/main/java/io/netty/util/internal/StringUtil.java b/common/src/main/java/io/netty/util/internal/StringUtil.java
@@ -74,7 +74,7 @@ public static String[] split(String value, char delim) {
             } else {
                 // Truncate trailing empty elements.
                 for (int i = res.size() - 1; i >= 0; i --) {
-                    if (res.get(i).length() == 0) {
+                    if (res.get(i).isEmpty()) {
                         res.remove(i);
                     } else {
                         break;
diff --git a/common/src/main/java/io/netty/util/internal/SystemPropertyUtil.java b/common/src/main/java/io/netty/util/internal/SystemPropertyUtil.java
@@ -67,7 +67,7 @@ public static String get(String key, String def) {
         if (key == null) {
             throw new NullPointerException("key");
         }
-        if (key.length() == 0) {
+        if (key.isEmpty()) {
             throw new IllegalArgumentException("key must not be empty.");
         }
 
@@ -104,7 +104,7 @@ public static boolean getBoolean(String key, boolean def) {
         }
 
         value = value.trim().toLowerCase();
-        if (value.length() == 0) {
+        if (value.isEmpty()) {
             return true;
         }
 
diff --git a/example/src/main/java/io/netty/example/telnet/TelnetServerHandler.java b/example/src/main/java/io/netty/example/telnet/TelnetServerHandler.java
@@ -48,7 +48,7 @@ public void messageReceived(ChannelHandlerContext ctx, String request) throws Ex
         // Generate and write a response.
         String response;
         boolean close = false;
-        if (request.length() == 0) {
+        if (request.isEmpty()) {
             response = "Please type something.\r\n";
         } else if (request.toLowerCase().equals("bye")) {
             response = "Have a good day!\r\n";
diff --git a/transport/src/main/java/io/netty/channel/local/LocalAddress.java b/transport/src/main/java/io/netty/channel/local/LocalAddress.java
@@ -56,7 +56,7 @@ public LocalAddress(String id) {
             throw new NullPointerException("id");
         }
         id = id.trim().toLowerCase();
-        if (id.length() == 0) {
+        if (id.isEmpty()) {
             throw new IllegalArgumentException("empty id");
         }
         this.id = id;

Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ public DefaultCookie(String name, String value) {`
`48`	`48`	`throw new NullPointerException("name");`
`49`	`49`	`}`
`50`	`50`	`name = name.trim();`
`51`		`- if (name.length() == 0) {`
	`51`	`+ if (name.isEmpty()) {`
`52`	`52`	`throw new IllegalArgumentException("empty name");`
`53`	`53`	`}`
`54`	`54`
`@@ -343,7 +343,7 @@ private static String validateValue(String name, String value) {`
`343`	`343`	`return null;`
`344`	`344`	`}`
`345`	`345`	`value = value.trim();`
`346`		`- if (value.length() == 0) {`
	`346`	`+ if (value.isEmpty()) {`
`347`	`347`	`return null;`
`348`	`348`	`}`
`349`	`349`	`for (int i = 0; i < value.length(); i ++) {`
Original file line number	Diff line number	Diff line change
`@@ -110,7 +110,7 @@ public static HttpMethod valueOf(String name) {`
`110`	`110`	`}`
`111`	`111`
`112`	`112`	`name = name.trim();`
`113`		`- if (name.length() == 0) {`
	`113`	`+ if (name.isEmpty()) {`
`114`	`114`	`throw new IllegalArgumentException("empty name");`
`115`	`115`	`}`
`116`	`116`
`@@ -137,7 +137,7 @@ public HttpMethod(String name) {`
`137`	`137`	`}`
`138`	`138`
`139`	`139`	`name = name.trim();`
`140`		`- if (name.length() == 0) {`
	`140`	`+ if (name.isEmpty()) {`
`141`	`141`	`throw new IllegalArgumentException("empty name");`
`142`	`142`	`}`
`143`	`143`
Original file line number	Diff line number	Diff line change
`@@ -85,7 +85,7 @@ public HttpVersion(String text, boolean keepAliveDefault) {`
`85`	`85`	`}`
`86`	`86`
`87`	`87`	`text = text.trim().toUpperCase();`
`88`		`- if (text.length() == 0) {`
	`88`	`+ if (text.isEmpty()) {`
`89`	`89`	`throw new IllegalArgumentException("empty text");`
`90`	`90`	`}`
`91`	`91`
`@@ -120,7 +120,7 @@ public HttpVersion(`
`120`	`120`	`}`
`121`	`121`
`122`	`122`	`protocolName = protocolName.trim().toUpperCase();`
`123`		`- if (protocolName.length() == 0) {`
	`123`	`+ if (protocolName.isEmpty()) {`
`124`	`124`	`throw new IllegalArgumentException("empty protocolName");`
`125`	`125`	`}`
`126`	`126`
Original file line number	Diff line number	Diff line change
`@@ -379,7 +379,7 @@ public boolean hasNext() throws EndOfDataDecoderException {`
`379`	`379`	`throw new EndOfDataDecoderException();`
`380`	`380`	`}`
`381`	`381`	`}`
`382`		`- return bodyListHttpData.size() > 0 && bodyListHttpDataRank < bodyListHttpData.size();`
	`382`	`+ return !bodyListHttpData.isEmpty() && bodyListHttpDataRank < bodyListHttpData.size();`
`383`	`383`	`}`
`384`	`384`
`385`	`385`	`/**`
Original file line number	Diff line number	Diff line change
`@@ -442,7 +442,7 @@ public void addBodyHttpData(InterfaceHttpData data) throws ErrorDataEncoderExcep`
`442`	`442`	`duringMixedMode = false;`
`443`	`443`	`}`
`444`	`444`	`InternalAttribute internal = new InternalAttribute();`
`445`		`- if (multipartHttpDatas.size() > 0) {`
	`445`	`+ if (!multipartHttpDatas.isEmpty()) {`
`446`	`446`	`// previously a data field so CRLF`
`447`	`447`	`internal.addValue("\r\n");`
`448`	`448`	`}`
`@@ -465,7 +465,7 @@ public void addBodyHttpData(InterfaceHttpData data) throws ErrorDataEncoderExcep`
`465`	`465`	`} else if (data instanceof FileUpload) {`
`466`	`466`	`FileUpload fileUpload = (FileUpload) data;`
`467`	`467`	`InternalAttribute internal = new InternalAttribute();`
`468`		`- if (multipartHttpDatas.size() > 0) {`
	`468`	`+ if (!multipartHttpDatas.isEmpty()) {`
`469`	`469`	`// previously a data field so CRLF`
`470`	`470`	`internal.addValue("\r\n");`
`471`	`471`	`}`
Original file line number	Diff line number	Diff line change
`@@ -133,7 +133,7 @@ public ChannelFuture handshake(Channel channel) {`
`133`	`133`	`// Get path`
`134`	`134`	`URI wsURL = getWebSocketUrl();`
`135`	`135`	`String path = wsURL.getPath();`
`136`		`- if (wsURL.getQuery() != null && wsURL.getQuery().length() > 0) {`
	`136`	`+ if (wsURL.getQuery() != null && !wsURL.getQuery().isEmpty()) {`
`137`	`137`	`path = wsURL.getPath() + "?" + wsURL.getQuery();`
`138`	`138`	`}`
`139`	`139`
Original file line number	Diff line number	Diff line change
`@@ -101,7 +101,7 @@ public ChannelFuture handshake(Channel channel) {`
`101`	`101`	`// Get path`
`102`	`102`	`URI wsURL = getWebSocketUrl();`
`103`	`103`	`String path = wsURL.getPath();`
`104`		`- if (wsURL.getQuery() != null && wsURL.getQuery().length() > 0) {`
	`104`	`+ if (wsURL.getQuery() != null && !wsURL.getQuery().isEmpty()) {`
`105`	`105`	`path = wsURL.getPath() + "?" + wsURL.getQuery();`
`106`	`106`	`}`
`107`	`107`