Utilize i.n.u.internal.ObjectUtil to assert Preconditions (handler) (#11170) (#11180)

Motivation:

NullChecks resulting in a NullPointerException or IllegalArgumentException, numeric ranges (>0, >=0) checks, not empty strings/arrays checks must never be anonymous but with the parameter or variable name which is checked. They must be specific and should not be done with an "OR-Logic" (if a == null || b == null) throw new NullPointerEx.

Modifications:

* import static relevant checks
* Replace manual checks with ObjectUtil methods

Result:

All checks needed are done with ObjectUtil, some exception texts are improved.

Fixes #11170

handler/src/main/java/io/netty/handler/ssl/ApplicationProtocolConfig.java

@@ -22,6 +22,7 @@ import javax.net.ssl.SSLEngine;
 
 import static io.netty.handler.ssl.ApplicationProtocolUtil.toList;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
 
 /**
  * Provides an {@link SSLEngine} agnostic way to configure a {@link ApplicationProtocolNegotiator}.
@@ -80,9 +81,7 @@ public final class ApplicationProtocolConfig {
         if (protocol == Protocol.NONE) {
             throw new IllegalArgumentException("protocol (" + Protocol.NONE + ") must not be " + Protocol.NONE + '.');
         }
-        if (supportedProtocols.isEmpty()) {
+        checkNonEmpty(supportedProtocols, "supportedProtocols");
-            throw new IllegalArgumentException("supportedProtocols must be not empty");
-        }
     }
 
     /**

handler/src/main/java/io/netty/handler/ssl/ApplicationProtocolUtil.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.ssl;
 
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -38,17 +40,10 @@ final class ApplicationProtocolUtil {
 
         List<String> result = new ArrayList<String>(initialListSize);
         for (String p : protocols) {
-            if (p == null || p.isEmpty()) {
+            result.add(checkNonEmpty(p, "p"));
-                throw new IllegalArgumentException("protocol cannot be null or empty");
-            }
-            result.add(p);
         }
 
-        if (result.isEmpty()) {
+        return checkNonEmpty(result, "result");
-            throw new IllegalArgumentException("protocols cannot empty");
-        }
-
-        return result;
     }
 
     static List<String> toList(String... protocols) {
@@ -62,16 +57,9 @@ final class ApplicationProtocolUtil {
 
         List<String> result = new ArrayList<String>(initialListSize);
         for (String p : protocols) {
-            if (p == null || p.isEmpty()) {
+            result.add(checkNonEmpty(p, "p"));
-                throw new IllegalArgumentException("protocol cannot be null or empty");
-            }
-            result.add(p);
         }
 
-        if (result.isEmpty()) {
+        return checkNonEmpty(result, "result");
-            throw new IllegalArgumentException("protocols cannot empty");
-        }
-
-        return result;
     }
 }

handler/src/main/java/io/netty/handler/ssl/OpenSslX509KeyManagerFactory.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.ssl;
 
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
+
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.internal.tcnative.SSL;
@@ -204,9 +206,7 @@ public final class OpenSslX509KeyManagerFactory extends KeyManagerFactory {
                             destroy();
                         }
                     }
-                    if (materialMap.isEmpty()) {
+                    checkNonEmpty(materialMap, "materialMap");
-                        throw new IllegalArgumentException("aliases must be non-empty");
-                    }
                 }
 
                 @Override

handler/src/main/java/io/netty/handler/ssl/PemX509Certificate.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.ssl;
 
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
+
 import java.math.BigInteger;
 import java.security.Principal;
 import java.security.PublicKey;
@@ -55,9 +57,7 @@ public final class PemX509Certificate extends X509Certificate implements PemEnco
     static PemEncoded toPEM(ByteBufAllocator allocator, boolean useDirect,
             X509Certificate... chain) throws CertificateEncodingException {
 
-        if (chain == null || chain.length == 0) {
+        checkNonEmpty(chain, "chain");
-            throw new IllegalArgumentException("X.509 certificate chain can't be null or empty");
-        }
 
         // We can take a shortcut if there is only one certificate and
         // it already happens to be a PemEncoded instance. This is the

handler/src/main/java/io/netty/handler/ssl/PseudoRandomFunction.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.ssl;
 
+import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
+
 import io.netty.util.internal.EmptyArrays;
 
 import javax.crypto.Mac;
@@ -59,9 +61,7 @@ final class PseudoRandomFunction {
      * @throws IllegalArgumentException if the algo could not be found.
      */
     static byte[] hash(byte[] secret, byte[] label, byte[] seed, int length, String algo) {
-        if (length < 0) {
+        checkPositiveOrZero(length, "length");
-            throw new IllegalArgumentException("You must provide a length greater than zero.");
-        }
         try {
             Mac hmac = Mac.getInstance(algo);
             hmac.init(new SecretKeySpec(secret, algo));

handler/src/main/java/io/netty/handler/ssl/ReferenceCountedOpenSslContext.java

@@ -27,7 +27,6 @@ import io.netty.util.ReferenceCounted;
 import io.netty.util.ResourceLeakDetector;
 import io.netty.util.ResourceLeakDetectorFactory;
 import io.netty.util.ResourceLeakTracker;
-import io.netty.util.internal.ObjectUtil;
 import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.SuppressJava6Requirement;
@@ -66,6 +65,7 @@ import javax.net.ssl.X509TrustManager;
 import static io.netty.handler.ssl.OpenSsl.DEFAULT_CIPHERS;
 import static io.netty.handler.ssl.OpenSsl.availableJavaCipherSuites;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
 import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
 
 /**
@@ -531,7 +531,7 @@ public abstract class ReferenceCountedOpenSslContext extends SslContext implemen
     @Deprecated
     @UnstableApi
     public final void setPrivateKeyMethod(OpenSslPrivateKeyMethod method) {
-        ObjectUtil.checkNotNull(method, "method");
+        checkNotNull(method, "method");
         Lock writerLock = ctxLock.writeLock();
         writerLock.lock();
         try {
@@ -861,9 +861,7 @@ public abstract class ReferenceCountedOpenSslContext extends SslContext implemen
             return 0;
         }
 
-        if (certChain.length == 0) {
+        checkNonEmpty(certChain, "certChain");
-            throw new IllegalArgumentException("certChain can't be empty");
-        }
 
         PemEncoded pem = PemX509Certificate.toPEM(allocator, true, certChain);
         try {

handler/src/main/java/io/netty/handler/ssl/ReferenceCountedOpenSslEngine.java

@@ -28,7 +28,6 @@ import io.netty.util.ResourceLeakDetector;
 import io.netty.util.ResourceLeakDetectorFactory;
 import io.netty.util.ResourceLeakTracker;
 import io.netty.util.internal.EmptyArrays;
-import io.netty.util.internal.ObjectUtil;
 import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.SuppressJava6Requirement;
@@ -75,6 +74,8 @@ import static io.netty.handler.ssl.SslUtils.PROTOCOL_TLS_V1_2;
 import static io.netty.handler.ssl.SslUtils.PROTOCOL_TLS_V1_3;
 import static io.netty.handler.ssl.SslUtils.SSL_RECORD_HEADER_LENGTH;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
+import static io.netty.util.internal.ObjectUtil.checkNotNullArrayParam;
 import static java.lang.Integer.MAX_VALUE;
 import static java.lang.Math.min;
 import static javax.net.ssl.SSLEngineResult.HandshakeStatus.FINISHED;
@@ -717,12 +718,8 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
     public final SSLEngineResult wrap(
             final ByteBuffer[] srcs, int offset, final int length, final ByteBuffer dst) throws SSLException {
         // Throw required runtime exceptions
-        if (srcs == null) {
+        checkNotNullWithIAE(srcs, "srcs");
-            throw new IllegalArgumentException("srcs is null");
+        checkNotNullWithIAE(dst, "dst");
-        }
-        if (dst == null) {
-            throw new IllegalArgumentException("dst is null");
-        }
 
         if (offset >= srcs.length || offset + length > srcs.length) {
             throw new IndexOutOfBoundsException(
@@ -1090,16 +1087,14 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
             final ByteBuffer[] dsts, int dstsOffset, final int dstsLength) throws SSLException {
 
         // Throw required runtime exceptions
-        ObjectUtil.checkNotNull(srcs, "srcs");
+        checkNotNullWithIAE(srcs, "srcs");
         if (srcsOffset >= srcs.length
                 || srcsOffset + srcsLength > srcs.length) {
             throw new IndexOutOfBoundsException(
                     "offset: " + srcsOffset + ", length: " + srcsLength +
                             " (expected: offset <= offset + length <= srcs.length (" + srcs.length + "))");
         }
-        if (dsts == null) {
+        checkNotNullWithIAE(dsts, "dsts");
-            throw new IllegalArgumentException("dsts is null");
-        }
         if (dstsOffset >= dsts.length || dstsOffset + dstsLength > dsts.length) {
             throw new IndexOutOfBoundsException(
                     "offset: " + dstsOffset + ", length: " + dstsLength +
@@ -1108,10 +1103,7 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
         long capacity = 0;
         final int dstsEndOffset = dstsOffset + dstsLength;
         for (int i = dstsOffset; i < dstsEndOffset; i ++) {
-            ByteBuffer dst = dsts[i];
+            ByteBuffer dst = checkNotNullArrayParam(dsts[i], i, "dsts");
-            if (dst == null) {
-                throw new IllegalArgumentException("dsts[" + i + "] is null");
-            }
             if (dst.isReadOnly()) {
                 throw new ReadOnlyBufferException();
             }
@@ -1121,10 +1113,7 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
         final int srcsEndOffset = srcsOffset + srcsLength;
         long len = 0;
         for (int i = srcsOffset; i < srcsEndOffset; i++) {
-            ByteBuffer src = srcs[i];
+            ByteBuffer src = checkNotNullArrayParam(srcs[i], i, "srcs");
-            if (src == null) {
-                throw new IllegalArgumentException("srcs[" + i + "] is null");
-            }
             len += src.remaining();
         }
 
@@ -1706,10 +1695,8 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
     }
 
     private void setEnabledProtocols0(String[] protocols, boolean cache) {
-        if (protocols == null) {
+        // This is correct from the API docs
-            // This is correct from the API docs
+        checkNotNullWithIAE(protocols, "protocols");
-            throw new IllegalArgumentException();
-        }
         int minProtocolIndex = OPENSSL_OP_NO_PROTOCOLS.length;
         int maxProtocolIndex = 0;
         for (String p: protocols) {
@@ -2349,8 +2336,8 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
 
         @Override
         public void putValue(String name, Object value) {
-            ObjectUtil.checkNotNull(name, "name");
+            checkNotNull(name, "name");
-            ObjectUtil.checkNotNull(value, "value");
+            checkNotNull(value, "value");
 
             final Object old;
             synchronized (this) {
@@ -2371,7 +2358,7 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
 
         @Override
         public Object getValue(String name) {
-            ObjectUtil.checkNotNull(name, "name");
+            checkNotNull(name, "name");
             synchronized (this) {
                 if (values == null) {
                     return null;
@@ -2382,7 +2369,7 @@ public class ReferenceCountedOpenSslEngine extends SSLEngine implements Referenc
 
         @Override
         public void removeValue(String name) {
-            ObjectUtil.checkNotNull(name, "name");
+            checkNotNull(name, "name");
 
             final Object old;
             synchronized (this) {

handler/src/main/java/io/netty/handler/ssl/SslContextBuilder.java

@@ -40,6 +40,8 @@ import java.util.Map;
 import static io.netty.util.internal.EmptyArrays.EMPTY_STRINGS;
 import static io.netty.util.internal.EmptyArrays.EMPTY_X509_CERTIFICATES;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
+import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
 
 /**
  * Builder for configuring a new SslContext for creation.
@@ -427,19 +429,14 @@ public final class SslContextBuilder {
      */
     public SslContextBuilder keyManager(PrivateKey key, String keyPassword, X509Certificate... keyCertChain) {
         if (forServer) {
-            checkNotNull(keyCertChain, "keyCertChain required for servers");
+            checkNonEmpty(keyCertChain, "keyCertChain"); // lgtm[java/dereferenced-value-may-be-null]
-            if (keyCertChain.length == 0) { // lgtm[java/dereferenced-value-may-be-null]
-                throw new IllegalArgumentException("keyCertChain must be non-empty");
-            }
             checkNotNull(key, "key required for servers");
         }
         if (keyCertChain == null || keyCertChain.length == 0) {
             this.keyCertChain = null;
         } else {
             for (X509Certificate cert: keyCertChain) {
-                if (cert == null) {
+                checkNotNullWithIAE(cert, "cert");
-                    throw new IllegalArgumentException("keyCertChain contains null entry");
-                }
             }
             this.keyCertChain = keyCertChain.clone();
         }

handler/src/main/java/io/netty/handler/ssl/SslHandler.java

@@ -75,6 +75,8 @@ import javax.net.ssl.SSLSession;
 
 import static io.netty.buffer.ByteBufUtil.ensureWritableSuccess;
 import static io.netty.handler.ssl.SslUtils.getEncryptedPacketLength;
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
 
 /**
  * Adds <a href="https://en.wikipedia.org/wiki/Transport_Layer_Security">SSL
@@ -458,16 +460,12 @@ public class SslHandler extends ByteToMessageDecoder implements ChannelOutboundH
     }
 
     public void setHandshakeTimeout(long handshakeTimeout, TimeUnit unit) {
-        ObjectUtil.checkNotNull(unit, "unit");
+        checkNotNull(unit, "unit");
         setHandshakeTimeoutMillis(unit.toMillis(handshakeTimeout));
     }
 
     public void setHandshakeTimeoutMillis(long handshakeTimeoutMillis) {
-        if (handshakeTimeoutMillis < 0) {
+        this.handshakeTimeoutMillis = checkPositiveOrZero(handshakeTimeoutMillis, "handshakeTimeoutMillis");
-            throw new IllegalArgumentException(
-                    "handshakeTimeoutMillis: " + handshakeTimeoutMillis + " (expected: >= 0)");
-        }
-        this.handshakeTimeoutMillis = handshakeTimeoutMillis;
     }
 
     /**
@@ -541,11 +539,8 @@ public class SslHandler extends ByteToMessageDecoder implements ChannelOutboundH
      * See {@link #setCloseNotifyFlushTimeout(long, TimeUnit)}.
      */
     public final void setCloseNotifyFlushTimeoutMillis(long closeNotifyFlushTimeoutMillis) {
-        if (closeNotifyFlushTimeoutMillis < 0) {
+        this.closeNotifyFlushTimeoutMillis = checkPositiveOrZero(closeNotifyFlushTimeoutMillis,
-            throw new IllegalArgumentException(
+                "closeNotifyFlushTimeoutMillis");
-                    "closeNotifyFlushTimeoutMillis: " + closeNotifyFlushTimeoutMillis + " (expected: >= 0)");
-        }
-        this.closeNotifyFlushTimeoutMillis = closeNotifyFlushTimeoutMillis;
     }
 
     /**
@@ -570,11 +565,8 @@ public class SslHandler extends ByteToMessageDecoder implements ChannelOutboundH
      * See {@link #setCloseNotifyReadTimeout(long, TimeUnit)}.
      */
     public final void setCloseNotifyReadTimeoutMillis(long closeNotifyReadTimeoutMillis) {
-        if (closeNotifyReadTimeoutMillis < 0) {
+        this.closeNotifyReadTimeoutMillis = checkPositiveOrZero(closeNotifyReadTimeoutMillis,
-            throw new IllegalArgumentException(
+                "closeNotifyReadTimeoutMillis");
-                    "closeNotifyReadTimeoutMillis: " + closeNotifyReadTimeoutMillis + " (expected: >= 0)");
-        }
-        this.closeNotifyReadTimeoutMillis = closeNotifyReadTimeoutMillis;
     }
 
     /**

handler/src/main/java/io/netty/handler/ssl/util/FingerprintTrustManagerFactoryBuilder.java

@@ -16,7 +16,8 @@
 
 package io.netty.handler.ssl.util;
 
-import io.netty.util.internal.ObjectUtil;
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -43,7 +44,7 @@ public final class FingerprintTrustManagerFactoryBuilder {
      * @param algorithm a hash algorithm
      */
     FingerprintTrustManagerFactoryBuilder(String algorithm) {
-        this.algorithm = ObjectUtil.checkNotNull(algorithm, "algorithm");
+        this.algorithm = checkNotNull(algorithm, "algorithm");
     }
 
     /**
@@ -53,8 +54,7 @@ public final class FingerprintTrustManagerFactoryBuilder {
      * @return the same builder
      */
     public FingerprintTrustManagerFactoryBuilder fingerprints(CharSequence... fingerprints) {
-        ObjectUtil.checkNotNull(fingerprints, "fingerprints");
+        return fingerprints(Arrays.asList(checkNotNull(fingerprints, "fingerprints")));
-        return fingerprints(Arrays.asList(fingerprints));
     }
 
     /**
@@ -64,11 +64,9 @@ public final class FingerprintTrustManagerFactoryBuilder {
      * @return the same builder
      */
     public FingerprintTrustManagerFactoryBuilder fingerprints(Iterable<? extends CharSequence> fingerprints) {
-        ObjectUtil.checkNotNull(fingerprints, "fingerprints");
+        checkNotNull(fingerprints, "fingerprints");
         for (CharSequence fingerprint : fingerprints) {
-            if (fingerprint == null) {
+            checkNotNullWithIAE(fingerprint, "fingerprint");
-                throw new IllegalArgumentException("One of the fingerprints is null");
-            }
             this.fingerprints.add(fingerprint.toString());
         }
         return this;

handler/src/main/java/io/netty/handler/stream/ChunkedNioStream.java

@@ -15,10 +15,12 @@
  */
 package io.netty.handler.stream;
 
+import static io.netty.util.internal.ObjectUtil.checkPositive;
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.util.internal.ObjectUtil;
 
 import java.nio.ByteBuffer;
 import java.nio.channels.ReadableByteChannel;
@@ -54,13 +56,8 @@ public class ChunkedNioStream implements ChunkedInput<ByteBuf> {
      *                  {@link #readChunk(ChannelHandlerContext)} call
      */
     public ChunkedNioStream(ReadableByteChannel in, int chunkSize) {
-        ObjectUtil.checkNotNull(in, "in");
+        this.in = checkNotNull(in, "in");
-        if (chunkSize <= 0) {
+        this.chunkSize = checkPositive(chunkSize, "chunkSize");
-            throw new IllegalArgumentException("chunkSize: " + chunkSize +
-                    " (expected: a positive integer)");
-        }
-        this.in = in;
-        this.chunkSize = chunkSize;
         byteBuffer = ByteBuffer.allocate(chunkSize);
     }
 

handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.stream;
 
+import static io.netty.util.internal.ObjectUtil.checkPositive;
+
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
@@ -81,10 +83,7 @@ public class ChunkedWriteHandler extends ChannelDuplexHandler {
      */
     @Deprecated
     public ChunkedWriteHandler(int maxPendingWrites) {
-        if (maxPendingWrites <= 0) {
+        checkPositive(maxPendingWrites, "maxPendingWrites");
-            throw new IllegalArgumentException(
-                    "maxPendingWrites: " + maxPendingWrites + " (expected: > 0)");
-        }
     }
 
     @Override

handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.traffic;
 
+import static io.netty.util.internal.ObjectUtil.checkPositive;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufHolder;
 import io.netty.channel.Channel;
@@ -164,15 +166,12 @@ public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler
      *            Must be positive.
      */
     protected AbstractTrafficShapingHandler(long writeLimit, long readLimit, long checkInterval, long maxTime) {
-        if (maxTime <= 0) {
+        this.maxTime = checkPositive(maxTime, "maxTime");
-            throw new IllegalArgumentException("maxTime must be positive");
-        }
 
         userDefinedWritabilityIndex = userDefinedWritabilityIndex();
         this.writeLimit = writeLimit;
         this.readLimit = readLimit;
         this.checkInterval = checkInterval;
-        this.maxTime = maxTime;
     }
 
     /**
@@ -346,10 +345,7 @@ public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler
      *            Must be positive.
      */
     public void setMaxTimeWait(long maxTime) {
-        if (maxTime <= 0) {
+        this.maxTime = checkPositive(maxTime, "maxTime");
-            throw new IllegalArgumentException("maxTime must be positive");
-        }
-        this.maxTime = maxTime;
     }
 
     /**
@@ -377,10 +373,7 @@ public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler
      *              Must be positive.
      */
     public void setMaxWriteDelay(long maxWriteDelay) {
-        if (maxWriteDelay <= 0) {
+        this.maxWriteDelay = checkPositive(maxWriteDelay, "maxWriteDelay");
-            throw new IllegalArgumentException("maxWriteDelay must be positive");
-        }
-        this.maxWriteDelay = maxWriteDelay;
     }
 
     /**

handler/src/main/java/io/netty/handler/traffic/GlobalChannelTrafficCounter.java

@@ -15,6 +15,8 @@
  */
 package io.netty.handler.traffic;
 
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
+
 import io.netty.handler.traffic.GlobalChannelTrafficShapingHandler.PerChannel;
 
 import java.util.concurrent.ScheduledExecutorService;
@@ -36,9 +38,7 @@ public class GlobalChannelTrafficCounter extends TrafficCounter {
     public GlobalChannelTrafficCounter(GlobalChannelTrafficShapingHandler trafficShapingHandler,
             ScheduledExecutorService executor, String name, long checkInterval) {
         super(trafficShapingHandler, executor, name, checkInterval);
-        if (executor == null) {
+        checkNotNullWithIAE(executor, "executor");
-            throw new IllegalArgumentException("Executor must not be null");
-        }
     }
 
     /**

handler/src/main/java/io/netty/handler/traffic/GlobalChannelTrafficShapingHandler.java

@@ -15,6 +15,10 @@
  */
 package io.netty.handler.traffic;
 
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
+import static io.netty.util.internal.ObjectUtil.checkPositive;
+import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler.Sharable;
@@ -147,9 +151,7 @@ public class GlobalChannelTrafficShapingHandler extends AbstractTrafficShapingHa
     void createGlobalTrafficCounter(ScheduledExecutorService executor) {
         // Default
         setMaxDeviation(DEFAULT_DEVIATION, DEFAULT_SLOWDOWN, DEFAULT_ACCELERATION);
-        if (executor == null) {
+        checkNotNullWithIAE(executor, "executor");
-            throw new IllegalArgumentException("Executor must not be null");
-        }
         TrafficCounter tc = new GlobalChannelTrafficCounter(this, executor, "GlobalChannelTC", checkInterval);
         setTrafficCounter(tc);
         tc.start();
@@ -299,9 +301,7 @@ public class GlobalChannelTrafficShapingHandler extends AbstractTrafficShapingHa
         if (maxDeviation > MAX_DEVIATION) {
             throw new IllegalArgumentException("maxDeviation must be <= " + MAX_DEVIATION);
         }
-        if (slowDownFactor < 0) {
+        checkPositiveOrZero(slowDownFactor, "slowDownFactor");
-            throw new IllegalArgumentException("slowDownFactor must be >= 0");
-        }
         if (accelerationFactor > 0) {
             throw new IllegalArgumentException("accelerationFactor must be <= 0");
         }
@@ -385,10 +385,7 @@ public class GlobalChannelTrafficShapingHandler extends AbstractTrafficShapingHa
      *            globally for all channels before write suspended is set.
      */
     public void setMaxGlobalWriteSize(long maxGlobalWriteSize) {
-        if (maxGlobalWriteSize <= 0) {
+        this.maxGlobalWriteSize = checkPositive(maxGlobalWriteSize, "maxGlobalWriteSize");
-            throw new IllegalArgumentException("maxGlobalWriteSize must be positive");
-        }
-        this.maxGlobalWriteSize = maxGlobalWriteSize;
     }
 
     /**

handler/src/main/java/io/netty/handler/traffic/TrafficCounter.java

@@ -15,7 +15,8 @@
  */
 package io.netty.handler.traffic;
 
-import io.netty.util.internal.ObjectUtil;
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
@@ -252,7 +253,7 @@ public class TrafficCounter {
      */
     public TrafficCounter(ScheduledExecutorService executor, String name, long checkInterval) {
 
-        this.name = ObjectUtil.checkNotNull(name, "name");
+        this.name = checkNotNull(name, "name");
         trafficShapingHandler = null;
         this.executor = executor;
 
@@ -276,13 +277,8 @@ public class TrafficCounter {
     public TrafficCounter(
             AbstractTrafficShapingHandler trafficShapingHandler, ScheduledExecutorService executor,
             String name, long checkInterval) {
-
+        this.name = checkNotNull(name, "name");
-        if (trafficShapingHandler == null) {
+        this.trafficShapingHandler = checkNotNullWithIAE(trafficShapingHandler, "trafficShapingHandler");
-            throw new IllegalArgumentException("trafficShapingHandler");
-        }
-
-        this.name = ObjectUtil.checkNotNull(name, "name");
-        this.trafficShapingHandler = trafficShapingHandler;
         this.executor = executor;
 
         init(checkInterval);