1, class
(1) class
l Groovy's class definition and Java similar
Ø Method can be based on class (STATIC) or instance
Ø can be public, protected or private
Ø Support common Java modifiers, such as Synchronized
l Groovy's different places: By default is public
l Groovy supports JavaBean mechanism: Groovybean
l Each Groovy class is a Java class with a zodical code / JVM. Any method is valid for Java, and vice versa.
l You can specify the parameter type and return type of the method, so you can work better in the usual Java code.
l You can use the above way to implement an interface or overload method
l If the type of method is omitted, the default java.lang.object will be used.
(2) script
l Groovy supports pure script without a statement, such as foo.groovy contains the following script:
Println "Nice Cheese Gromit!"
l The process of running scripts:
Ø Compile into foo.class (there will be some inside into the category), this class extension Groovy.lang.Script
Ø Execute the automatically generated main method
Ø Instantiate FOO class
Ø Call the RUN method to perform scripting content
l You can execute a script in the Java code, and you can also transfer variables to the script.
l foo.groovy content is modified as follows
Println "Nice $ {Cheese} GROTI!"
l The following is the USEFOO class that performs scripts.
Import groovy.lang.binding;
Import groovy.lang.script;
Public class usefoo {
Public static void main (String [] args) {
Binding binding = new binding ();
Binding.Setvariable ("Cheese", "ChedDar");
Script foo = new foo (binding);
Foo.Run ();
}
}
l Usefoo running results: Nice Cheddar Gromit!
l The method of executing the script is to create a Foo class instance and call its RUN method.
l Foo class has a constructor with a binding parameter, which can set the value to the attribute variable in the script via the Binding class's setvariable method.
l Foo class has a constructor without parameters, uses when not transferring attribute variables
l After the script is over, any variable created in the script will be in Binding for access in Java.
l Remove the foo.groovy content as follows
Println "Nice $ {Cheese} GROTI!"
Cheese = "Changed"
l Usefoo class modifications to:
Import groovy.lang.binding;
Import groovy.lang.script;
Public class usefoo {
Public static void main (String [] args) {
Binding binding = new binding (); binding.setvariable ("cheese", "cheddar");
Script foo = new foo (binding);
Foo.Run ();
Println Binding.getvariable ("Cheese");
}
}
l Usefoo runs the result:
Nice Cheddar Gromit!
changed
(3) Functions in scripts
l Different from the Class-based Groovy, the function in the pure script is declared by DEF keyword
DEF foo (list, value) {
Println "Calling function foo () with param $ {value}
List << Value
}
X = []
Foo (x, 1)
Foo (x, 2)
askERT X == [1, 2]
Println "Creating List $ {x}"
