gradle-master/subprojects/jvm-services/src/main/java/org/gradle/jvm/toolchain/internal/SdkmanInstallationSupplier.java
/*
 * Copyright 2020 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.jvm.toolchain.internal;

import org.gradle.api.Transformer;
import org.gradle.api.provider.Provider;
import org.gradle.api.provider.ProviderFactory;

import javax.inject.Inject;
import java.io.File;
import java.util.Collections;
import java.util.Set;

public class SdkmanInstallationSupplier extends AutoDetectingInstallationSupplier {

    private Provider<String> candidatesDir;

    @Inject
    public SdkmanInstallationSupplier(ProviderFactory factory) {
        super(factory);
        candidatesDir = getEnvironmentProperty("SDKMAN_CANDIDATES_DIR").orElse(defaultSdkmanCandidatesDirectory());
    }

    @Override
    public String getSourceName() {
        return "SDKMAN!";
    }

    @Override
    protected Set<InstallationLocation> findCandidates() {
        return candidatesDir.map(findJavaCandidates()).getOrElse(Collections.emptySet());
    }

    private String defaultSdkmanCandidatesDirectory() {
        return new File(System.getProperty("user.home"), ".sdkman/candidates").getAbsolutePath();
    }

    private Transformer<Set<InstallationLocation>, String> findJavaCandidates() {
        return candidatesDir -> {
            final File root = new File(candidatesDir, "java");
            return FileBasedInstallationFactory.fromDirectory(root, getSourceName());
        };
    }

}
