com.diffplug.gradle

Interface JavaExecable

All Superinterfaces:

Serializable, Throwing.Runnable, Throwing.Specific.Runnable<Throwable>

public interface JavaExecable
extends Serializable, Throwing.Runnable

Easy way to execute code from a Gradle plugin in a separate JVM.

Create an class which implements JavaExecable. It should have some fields which are input, some fields which are output, and a run() method.

Here’s what happens when you call exec(Project, JavaExecable),

• Write the JavaExecable to a temporary file using Serializable.
• Launch a new JVM with the same classpath as the project’s buildscript, and pass the location of that temp file.
• The new JVM loads the JavaExecable from the temp file, calls run(), writes it back to the temp file, then exits.
• Back in gradle, we deserialize the tempfile and return the result.

If the JavaExecable happens to throw an exception, it will be transparently rethrown within the calling thread.

Example usage:

static class Incrementer implements JavaExecable {
    private static final long serialVersionUID = -5728572785844814830L;

    int input;
    int output;

    Incrementer(int input) {
        this.input = input;
    }

    public int getOutput() {
        return output;
    }

    public void run() throws Throwable {
        output = input + 1;
    }
}

// obvious
public void testInternal() {
    Incrementer example = new Incrementer(5);
    example.run();
    Assert.assertEquals(6, example.output);
}

// magic!
public void testExternal() throws Throwable {
    Incrementer example = new Incrementer(5);
    Incrementer result = JavaExecable.execWithoutGradle(example);
    Assert.assertEquals(6, result.output);
}

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	JavaExecable.Mode Encapsulates whether something is run internally or externally.

Field Summary

Fields

Modifier and Type	Field and Description
static String	BUILDSCRIPT_CLASSPATH

Method Summary

Modifier and Type	Method and Description
static <T extends JavaExecable> T	exec(Project project, T input)
static <T extends JavaExecable> T	exec(Project project, T input, Action<JavaExecSpec> settings)
static <T extends JavaExecable> T	execWithoutGradle(T input)
static <T extends JavaExecable> T	execWithoutGradle(T input, Action<JavaExecSpec> settings)
static void	main(String[] args) Main which works in conjunction with exec(Project, JavaExecable, Action).

Methods inherited from interface com.diffplug.common.base.Throwing.Specific.Runnable

run

Field Detail

BUILDSCRIPT_CLASSPATH

static final String BUILDSCRIPT_CLASSPATH

See Also:

Constant Field Values

Method Detail

exec

static <T extends JavaExecable> T exec(Project project,
                                       T input,
                                       Action<JavaExecSpec> settings)
                                throws Throwable

Parameters:

project - the project on which we’ll call Project.javaexec(Action).

input - the JavaExecable which we’ll take as input and call run() on.

settings - any extra settings you’d like to set on the JavaExec (e.g. heap)

Returns:

the JavaExecable after it has had run() called.

Throws:

Throwable

exec

static <T extends JavaExecable> T exec(Project project,
                                       T input)
                                throws Throwable

Throws:

Throwable

See Also:

exec(Project, JavaExecable, Action)

execWithoutGradle

static <T extends JavaExecable> T execWithoutGradle(T input,
                                                    Action<JavaExecSpec> settings)
                                             throws Throwable

Throws:

Throwable

See Also:

exec(Project, JavaExecable, Action)

execWithoutGradle

static <T extends JavaExecable> T execWithoutGradle(T input)
                                             throws Throwable

Throws:

Throwable

See Also:

exec(Project, JavaExecable, Action)

main

static void main(String[] args)
          throws IOException

Main which works in conjunction with exec(Project, JavaExecable, Action).

Throws:

IOException