Java arrays can be created either using a literal as described in the previous section, or if it should be a new array with a fixed size, one of the methods from ArrayLiterals can be used. The generic newArrayOfSize int method works for all reference types, while there is a specific factory method for each primitive type.
Retrieving and setting values of arrays is done through the extension methods get int and set int, T which are specifically overloaded for arrays and are translated directly to the equivalent native Java code myArray[int]. Furthermore arrays are automatically converted to lists java. List when needed. This works similar to how boxing and unboxing between primitives and their respective wrapper types work. A type cast behaves exactly like casts in Java, but has a slightly more readable syntax.
Type casts bind stronger than any other operator but weaker than feature calls. The conformance rules for casts are defined in the Java Language Specification.
Here are some examples:. Dispatch methods are another alternative to casts that offers the potential to enhance the number of expected and handled types in subclasses. There are a couple of common predefined infix operators. These operators are not limited to operations on certain types. Instead an operator-to-method mapping allows to redefine the operators for any type just by implementing the corresponding method signature. As an example, the runtime library contains a class BigDecimalExtensions that defines operators for BigDecimals.
The following code is therefore perfectly valid:. The table above also defines the operator precedence in ascending order. The blank lines separate precedence levels. Parentheses can be used to adjust the default precedence and associativity. That means that the right hand operand might not be evaluated at all in the following cases:. Still you can overload these operators for your types or even override it for booleans, in which case both operands are always evaluated and the defined method is invoked, i.
So you can write:. In addition these operators are overloaded for all instances of java. So you can also write. In addition to null-safe feature calls Xtend supports the elvis operator known from Groovy.
The with operator is very handy when you want to initialize objects or when you want to use a particular instance a couple of time in subsequent lines of code. It simply passes the left hand side argument to the lambda on the right hand and returns the left hand after that. There are three different range operators. The most useful ones are.. In addition there is the inclusive range, which is nice if you know both ends well. In the movies example the range is used to check whether a movie was made in a certain decade:.
Please keep in mind that there are other means to iterator lists, too. For example, you may want to use the forEach extension. Sometimes you want to use a pair of two elements locally without introducing a new structure.
The lack of properties in Java leads to a lot of syntactic noise when working with data objects. As Xtend is designed to integrate with existing Java APIs it respects the Java Beans convention, hence you can call a setter using an assignment:. The setter is only used if the field is not accessible from the given context. The return type of an assignment is the type of the right hand side, in case it is a simple assignment.
If it is translated to a setter method it yields whatever the setter method returns. Compound assignment operators can be used as a shorthand for the assignment of a binary expression. Compound assignments work automatically when the infix operator is declared. The following compound assignment operators are supported:. The block expression allows to have imperative code sequences.
It consists of a sequence of expressions. The value of the last expression in the block is the value of the complete block. The type of a block is also the type of the last expression. Empty blocks return null and have the type Object.
A block expression is surrounded by curly braces. The expressions in a block can be terminated by an optional semicolon. Variable declarations are only allowed within blocks. They are visible from any subsequent expressions in the block. A variable declaration starting with the keyword val denotes a value, which is essentially a final, unsettable variable.
Shadowing variables from outer scopes is not allowed, the only exception is the implicit variable it. Variables declared outside of a lambda expression using the var keyword are not accessible from within the lambda expressions.
A local variable can be marked with the extension keyword to make its methods available as extensions see extension provider. The type of the variable itself can either be explicitly declared or it can be inferred from the initializer expression. Here is an example for an explicitly declared type:. In such cases, the type of the right hand expression must conform to the type of the expression on the left side.
A simple name can refer to a local field, variable or parameter. In addition it can point to a method with zero arguments, since empty parentheses are optional.
If there is no field with the given name and also no method with the name and zero parameters accessible, a simple name binds to a corresponding Java-Bean getter method if available:.
Like in Java the current instance of the class is bound to this. This allows for either qualified field access or method invocations like in:. You can use the variable name it to get the same behavior for any variable or parameter:. Another speciality of the variable it is that it is allowed to be shadowed. This is especially useful when used together with lambda expressions. As this is bound to the surrounding object in Java, it can be used in finer-grained constructs such as lambda expressions.
That is why it. For accessing a static field or method you can use the recommended Java syntax or the more explicit double colon That means, the following epxressions are pairwise equivalent:. Alternatively you could import the method or field using a static import. Checking for null references can make code very unreadable. In many situations it is ok for an expression to return null if a receiver was null. Xtend supports the safe navigation operator?. Arguments that would be passed to the method are only evaluated if the method will be invoked at all.
For primitive types the default value is returned e. This may not be what you want in some cases, so a warning will be raised by default. You can turn that off in the preferences if you wish. Constructor calls have the same syntax as in Java. The only difference is that empty parentheses are optional:. A lambda expression is basically a piece of code wrapped into an object to pass it around.
As a Java developer it is best to think of a lambda expression as an anonymous class with a single method, i. This has been improved with Java 8 lambda expressions , which are conceptually very similar to Xtend lambda expressions.
Depending on the selected target language version, Xtend lambdas are translated differently to Java: Java lambdas are generated for Java 8 since 2. As you might have guessed, a lambda expression is surrounded by square brackets inspired from Smalltalk. Similarly to a method, a lambda expression may declare parameters. I am able to lift weights for an hour and can follow it with basketball, swimming or any other cardio without losing too much energy. If you're someone who does morning workouts while fasted, these are for you!
Greg G. This is not one of them. I continued to drink this as my workouts evolved to running and weight lifting. Despite always being a terrible runner I simply never felt that "runner's high", was never able to run very far, and was usually miserable my runs, while never really increasing too far in distance, seemed to require less effort, making them more tolerable.
Click here to read more! Xtend BCAAs is a great allrounder, it can be used before, during or after your workouts that prolongs the intensity of your workout, burns fat and builds muscle. This is definitely a BCAA to add to your stack!
Get perks Join the fam, get rewards, exclusive offers and more! Your email. Same day dispatch before 3pm Get discount. Create your account Lost password? First name. Last name. Your cart is empty. What Xtend can do for you Session details Status:. Speaker s :. Experience level:. Session Track:. Built on Eclipse. Session Type:. Objective of the presentation:.
Showing how the language features of the Eclipse Xtend programming language allow for more ergonomic and concise code and API than its Java equivalents; as well as easy extension of existing third party code and selective back-porting of newer features of third party code.
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