Use Supplier<String> support in Assert in spring-core

This commit makes use of the new Supplier<String> variants of utility
methods in org.springframework.util.Assert within the spring-core
module.

Issue: SPR-14450

spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java

@@ -224,10 +224,9 @@ public abstract class GenericTypeResolver {
 	}
 
 	private static Class<?> getSingleGeneric(ResolvableType resolvableType) {
-		if (resolvableType.getGenerics().length > 1) {
-			throw new IllegalArgumentException("Expected 1 type argument on generic interface [" +
-					resolvableType + "] but found " + resolvableType.getGenerics().length);
-		}
+		Assert.isTrue(resolvableType.getGenerics().length == 1,
+				() -> "Expected 1 type argument on generic interface [" + resolvableType +
+				"] but found " + resolvableType.getGenerics().length);
 		return resolvableType.getGeneric().resolve();
 	}
 

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -668,9 +668,7 @@ public class MethodParameter {
 
 	private static int validateIndex(Executable executable, int parameterIndex) {
 		int count = executable.getParameterCount();
-		if (parameterIndex >= count) {
-			throw new IllegalArgumentException("Parameter index needs to be between 0 and " + (count - 1));
-		}
+		Assert.isTrue(parameterIndex < count, () -> "Parameter index needs to be between 0 and " + (count - 1));
 		return parameterIndex;
 	}
 

spring-core/src/main/java/org/springframework/core/annotation/AnnotationAttributes.java

 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -480,18 +480,14 @@ public class AnnotationAttributes extends LinkedHashMap<String, Object> {
 	}
 
 	private void assertAttributePresence(String attributeName, Object attributeValue) {
-		if (attributeValue == null) {
-			throw new IllegalArgumentException(String.format(
-					"Attribute '%s' not found in attributes for annotation [%s]", attributeName, this.displayName));
-		}
+		Assert.notNull(attributeValue, () -> String.format("Attribute '%s' not found in attributes for annotation [%s]",
+				attributeName, this.displayName));
 	}
 
 	private void assertAttributePresence(String attributeName, List<String> aliases, Object attributeValue) {
-		if (attributeValue == null) {
-			throw new IllegalArgumentException(String.format(
-					"Neither attribute '%s' nor one of its aliases %s was found in attributes for annotation [%s]",
-					attributeName, aliases, this.displayName));
-		}
+		Assert.notNull(attributeValue, () -> String.format(
+				"Neither attribute '%s' nor one of its aliases %s was found in attributes for annotation [%s]",
+				attributeName, aliases, this.displayName));
 	}
 
 	private void assertNotException(String attributeName, Object attributeValue) {

spring-core/src/main/java/org/springframework/core/annotation/MapAnnotationAttributeExtractor.java

@@ -24,6 +24,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 import static org.springframework.core.annotation.AnnotationUtils.*;
@@ -120,11 +121,9 @@ class MapAnnotationAttributeExtractor extends AbstractAliasAwareAnnotationAttrib
 			}
 
 			// if still null
-			if (attributeValue == null) {
-				throw new IllegalArgumentException(String.format(
-						"Attributes map %s returned null for required attribute '%s' defined by annotation type [%s].",
-						attributes, attributeName, annotationType.getName()));
-			}
+			Assert.notNull(attributeValue, () -> String.format(
+					"Attributes map %s returned null for required attribute '%s' defined by annotation type [%s].",
+					attributes, attributeName, annotationType.getName()));
 
 			// finally, ensure correct type
 			Class<?> requiredReturnType = attributeMethod.getReturnType();
@@ -162,13 +161,11 @@ class MapAnnotationAttributeExtractor extends AbstractAliasAwareAnnotationAttrib
 					converted = true;
 				}
 
-				if (!converted) {
-					throw new IllegalArgumentException(String.format(
-							"Attributes map %s returned a value of type [%s] for attribute '%s', " +
-							"but a value of type [%s] is required as defined by annotation type [%s].",
-							attributes, actualReturnType.getName(), attributeName, requiredReturnType.getName(),
-							annotationType.getName()));
-				}
+				Assert.isTrue(converted, () -> String.format(
+						"Attributes map %s returned a value of type [%s] for attribute '%s', " +
+						"but a value of type [%s] is required as defined by annotation type [%s].",
+						attributes, actualReturnType.getName(), attributeName, requiredReturnType.getName(),
+						annotationType.getName()));
 			}
 		}
 

spring-core/src/main/java/org/springframework/core/convert/support/ConversionUtils.java

@@ -20,6 +20,7 @@ import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import org.springframework.util.Assert;
 
 /**
  * Internal utilities for the conversion package.
@@ -71,10 +72,7 @@ abstract class ConversionUtils {
 		while (enumType != null && !enumType.isEnum()) {
 			enumType = enumType.getSuperclass();
 		}
-		if (enumType == null) {
-			throw new IllegalArgumentException(
-					"The target type " + targetType.getName() + " does not refer to an enum");
-		}
+		Assert.notNull(enumType, () -> "The target type " + targetType.getName() + " does not refer to an enum");
 		return enumType;
 	}
 

spring-core/src/main/java/org/springframework/core/io/InputStreamResource.java

 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -19,6 +19,8 @@ package org.springframework.core.io;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.springframework.util.Assert;
+
 /**
  * {@link Resource} implementation for a given {@link InputStream}.
  * <p>Should only be used if no other specific {@code Resource} implementation
@@ -62,9 +64,7 @@ public class InputStreamResource extends AbstractResource {
 	 * @param description where the InputStream comes from
 	 */
 	public InputStreamResource(InputStream inputStream, String description) {
-		if (inputStream == null) {
-			throw new IllegalArgumentException("InputStream must not be null");
-		}
+		Assert.notNull(inputStream, "InputStream must not be null");
 		this.inputStream = inputStream;
 		this.description = (description != null ? description : "");
 	}

spring-core/src/main/java/org/springframework/util/backoff/ExponentialBackOff.java

@@ -16,6 +16,8 @@
 
 package org.springframework.util.backoff;
 
+import org.springframework.util.Assert;
+
 /**
  * Implementation of {@link BackOff} that increases the back off period for each
  * retry attempt. When the interval has reached the {@link #setMaxInterval(long)
@@ -169,10 +171,8 @@ public class ExponentialBackOff implements BackOff {
 	}
 
 	private void checkMultiplier(double multiplier) {
-		if (multiplier < 1) {
-			throw new IllegalArgumentException("Invalid multiplier '" + multiplier + "'. Should be equal" +
-					"or higher than 1. A multiplier of 1 is equivalent to a fixed interval");
-		}
+		Assert.isTrue(multiplier >= 1, () -> "Invalid multiplier '" + multiplier + "'. Should be greater than " +
+					"or equal to 1. A multiplier of 1 is equivalent to a fixed interval.");
 	}