Guava Preconditions class usage example

CheckNotNullExample.java

void setObject(Integer number) {
    this.number = checkNotNull(number);
}

MessageWithArgumentsExample.java

checkArgument(count > 0, "Invalid count %s: should be greater than zero", count);

pom.xml

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>10.0.1</version>
</dependency>

WithoutPreconditions.java

if (count <= 0) {
    throw IllegalArgumentException("Count should be greater than zero");
}

WithPreconditions.java

import static com.google.common.base.Preconditions.checkArgument;

checkArgument(count > 0, "Count should be greater than zero");