gradle-master/subprojects/maven/src/main/java/org/gradle/api/publish/maven/tasks/AbstractPublishToMaven.java
/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.gradle.api.publish.maven.tasks;

import org.gradle.api.DefaultTask;
import org.gradle.api.InvalidUserDataException;
import org.gradle.api.file.FileCollection;
import org.gradle.api.publish.maven.MavenPublication;
import org.gradle.api.publish.maven.internal.publication.MavenPublicationInternal;
import org.gradle.api.publish.maven.internal.publisher.MavenDuplicatePublicationTracker;
import org.gradle.api.publish.maven.internal.publisher.MavenPublishers;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.PathSensitivity;
import org.gradle.internal.serialization.Transient;
import org.gradle.work.DisableCachingByDefault;

import javax.inject.Inject;
import java.util.concurrent.Callable;

import static org.gradle.internal.serialization.Transient.varOf;

/**
 * Base class for tasks that publish a {@link org.gradle.api.publish.maven.MavenPublication}.
 *
 * @since 2.4
 */
@DisableCachingByDefault(because = "Abstract super-class, not to be instantiated directly")
public abstract class AbstractPublishToMaven extends DefaultTask {

    private final Transient.Var<MavenPublicationInternal> publication = varOf();

    public AbstractPublishToMaven() {
        // Allow the publication to participate in incremental build
        getInputs().files((Callable<FileCollection>) () -> {
            MavenPublicationInternal publicationInternal = getPublicationInternal();
            return publicationInternal == null ? null : publicationInternal.getPublishableArtifacts().getFiles();
        })
            .withPropertyName("publication.publishableFiles")
            .withPathSensitivity(PathSensitivity.NAME_ONLY);

        // Should repositories be able to participate in incremental?
        // At the least, they may be able to express themselves as output files
        // They *might* have input files and other dependencies as well though
        // Inputs: The credentials they need may be expressed in a file
        // Dependencies: Can't think of a case here
    }

    /**
     * The publication to be published.
     *
     * @return The publication to be published
     */
    @Internal
    public MavenPublication getPublication() {
        return publication.get();
    }

    /**
     * Sets the publication to be published.
     *
     * @param publication The publication to be published
     */
    public void setPublication(MavenPublication publication) {
        this.publication.set(toPublicationInternal(publication));
    }

    @Internal
    protected MavenPublicationInternal getPublicationInternal() {
        return toPublicationInternal(getPublication());
    }

    private static MavenPublicationInternal toPublicationInternal(MavenPublication publication) {
        if (publication == null) {
            return null;
        } else if (publication instanceof MavenPublicationInternal) {
            return (MavenPublicationInternal) publication;
        } else {
            throw new InvalidUserDataException(
                String.format(
                    "publication objects must implement the '%s' interface, implementation '%s' does not",
                    MavenPublicationInternal.class.getName(),
                    publication.getClass().getName()
                )
            );
        }
    }

    @Inject
    protected MavenPublishers getMavenPublishers() {
        throw new UnsupportedOperationException();
    }

    @Inject
    protected MavenDuplicatePublicationTracker getDuplicatePublicationTracker() {
        throw new UnsupportedOperationException();
    }
}
