Are you fed up with launching your heavy-weighted java eclipse IDE when you just need to create a quick java class to do some testing (by the way if someone knows an equivalent of Snippet Compiler but for Java that would interest me) ? Don’t you miss your simple notepad just because it would need a little twist ? Or maybe you’re just learning Java with an amazing editor like BlueJ which still lacks code generation. Using this lighweight text DSL or Domain Specific Language is a solution which will hugely improve your productivity (especially if you wrap it inside a snippet protocol).

We saw last time how it was incredibly simple to create a C# code generator, it’s now even easier to write the Java code generator by duplicating the C# code and customizing it for java (install and launch rebol’s console then copy and paste the code below):

generate-code: func[][
    attributes: parse/all attributes-list ","
    switch Language [
        "C#" [generate-code-csharp attributes]
        "java" [generate-code-java attributes]
    ] /default [print ["Language" Language "not yet implemented"]]
]

generate-code-java: func[attributes][
    package: if/else ((answer: ask "package (ex.:MyApp): ") = "") ["MyApp"][answer]
    class-name: if/else ((answer: ask "class-name (ex.: Cperson): ") = "") ["CPerson"][answer]
    private-prefix: "_"
    code-template: {// Generated by http://www.reboltutorial.com

package <%package%>;

    public class <%class-name%>
    {
        // private members
        <%private-members%>

        // empty constructor
        public <%class-name%> ()
        {
        }

        // full constructor
        public <%class-name%> (<%private-constructor-arguments-list%>)
        {
            <%private-constructor-body%>
        }

       // public accessors
        <%public-accessors%>
    }

}; end of Java class template

private-members-template: {<%attribute-type%> <%private-prefix%><%attribute-name%>;}

private-constructor-arguments-list-template: {<%attribute-type%> <%attribute-name%>}
private-constructor-body-template: {<%private-prefix%><%attribute-name%> = <%attribute-name%>;}
public-accessors-template: {//Accessors for <%attribute-name%>
        public <%attribute-type%> get<%attribute-name%>() {
            return <%private-prefix%><%attribute-name%>;
        }
        public void set<%attribute-name%>(<%attribute-type%> <%attribute-name%>) {
            <%private-prefix%><%attribute-name%>=<%attribute-name%>;
        }
}

    private-members: ""
    private-constructor-arguments-list: ""
    private-constructor-body: ""
    public-accessors: ""

    n: length? attributes
    counter: 0
    foreach attribute attributes [
        counter: counter + 1
        attribute-name: trim/all attribute; remove all whitespaces
        attribute-type: if/else ((answer: ask ["attribute-type for" attribute "(ex. String) : " ]) = "") ["String"][answer]

        if (counter > 1) [
            append private-members "        "
            append private-constructor-body "            "
            append public-accessors "        "
        ]

        append private-members build-markup private-members-template
        append private-constructor-arguments-list build-markup private-constructor-arguments-list-template
        append private-constructor-body build-markup private-constructor-body-template
        append public-accessors build-markup public-accessors-template

        if (counter < n) [
            append private-members newline
            append private-constructor-arguments-list ", "
            append private-constructor-body newline
        ]
    ]
    source-code: build-markup code-template
    write clipboard:// source-code
    Print "source code copied into clipboard ..."
    input
]

Now test the code by typing (or pasting) in rebol’s console:

phrase: "Create a Java class with Id, First Name, Last Name, Birth Date"

rule: ["Create a " copy Language to " class" thru " with " copy attributes-list to end (
generate-code)]

parse phrase rule

This is the code generated:

// Generated by http://www.reboltutorial.com

package MyApp;

    public class CPerson
    {
        // private members
        String _Id;
        String _FirstName;
        String _LastName;
        String _BirthDate;

        // empty constructor
        public CPerson ()
        {
        }

        // full constructor
        public CPerson (String Id, String FirstName, String LastName, String BirthDate)
        {
            _Id = Id;
            _FirstName = FirstName;
            _LastName = LastName;
            _BirthDate = BirthDate;
        }

       // public accessors
        //Accessors for Id
        public String getId() {
            return _Id;
        }
        public void setId(String Id) {
            _Id=Id;
        }
        //Accessors for FirstName
        public String getFirstName() {
            return _FirstName;
        }
        public void setFirstName(String FirstName) {
            _FirstName=FirstName;
        }
        //Accessors for LastName
        public String getLastName() {
            return _LastName;
        }
        public void setLastName(String LastName) {
            _LastName=LastName;
        }
        //Accessors for BirthDate
        public String getBirthDate() {
            return _BirthDate;
        }
        public void setBirthDate(String BirthDate) {
            _BirthDate=BirthDate;
        }

    }

You can test it for example with BlueJ:

You can execute the code over the internet by typing:

do http://rebcode.com/dsl

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