DotenvBuilder.java

package io.github.cdimascio.dotenv;

import io.github.cdimascio.dotenv.internal.DotenvParser;
import io.github.cdimascio.dotenv.internal.DotenvReader;

import java.util.*;

import static java.util.stream.Collectors.*;

/**
 * Builds and loads and {@link Dotenv} instance.
 * @see Dotenv#configure()
 */
public class DotenvBuilder {
    private String filename = ".env";
    private String directoryPath = "./";
    private boolean systemProperties = false;
    private boolean throwIfMissing = true;
    private boolean throwIfMalformed = true;

    /**
     * Sets the directory containing the .env file.
     * @param path the directory containing the .env file
     * @return this {@link DotenvBuilder}
     */
    public DotenvBuilder directory(final String path) {
        this.directoryPath = path;
        return this;
    }
    /**
     * Sets the name of the .env file. The default is .env.
     * @param name the filename
     * @return this {@link DotenvBuilder}
     */
    public DotenvBuilder filename(final String name) {
        filename = name;
        return this;
    }

    /**
     * Does not throw an exception when .env is missing.
     * @return this {@link DotenvBuilder}
     */
    public DotenvBuilder ignoreIfMissing() {
        throwIfMissing = false;
        return this;
    }

    /**
     * Does not throw an exception when .env is malformed.
     * @return this {@link DotenvBuilder}
     */
    public DotenvBuilder ignoreIfMalformed() {
        throwIfMalformed = false;
        return this;
    }

    /**
     * Sets each environment variable as system properties.
     * @return this {@link DotenvBuilder}
     */
    public DotenvBuilder systemProperties() {
        systemProperties = true;
        return this;
    }

    /**
     * Load the contents of .env into the virtual environment.
     * @return a new {@link Dotenv} instance
     * @throws DotenvException when an error occurs
     */
    public Dotenv load() throws DotenvException {
        final var reader = new DotenvParser(
                                new DotenvReader(directoryPath, filename),
                                throwIfMissing, throwIfMalformed);
        final List<DotenvEntry> env = reader.parse();
        if (systemProperties) {
            env.forEach(it -> System.setProperty(it.getKey(), it.getValue()));
        }

        return new DotenvImpl(env);
    }

    static class DotenvImpl implements Dotenv {
        private final Map<String, String> envVars;
        private final Set<DotenvEntry> set;
        private final Set<DotenvEntry> setInFile;
        public DotenvImpl(final List<DotenvEntry> envVars) {
            final Map<String, String> envVarsInFile =
                envVars.stream()
                       .collect(toMap(DotenvEntry::getKey, DotenvEntry::getValue, (a, b) -> b));

            this.envVars = new HashMap<>(envVarsInFile);
            this.envVars.putAll(System.getenv());

            this.set =
                this.envVars.entrySet()
                            .stream()
                            .map(it -> new DotenvEntry(it.getKey(), it.getValue()))
                            .collect(collectingAndThen(toSet(), Collections::unmodifiableSet));

            this.setInFile =
                envVarsInFile.entrySet()
                             .stream()
                             .map(it -> new DotenvEntry(it.getKey(), it.getValue()))
                             .collect(collectingAndThen(toSet(), Collections::unmodifiableSet));
        }

        @Override
        public Set<DotenvEntry> entries() {
            return set;
        }

        @Override
        public Set<DotenvEntry> entries(final Dotenv.Filter filter) {
            return filter == null ? entries() : setInFile;

        }

        @Override
        public String get(final String key) {
            final String value = System.getenv(key);
            return value == null ? envVars.get(key) : value;
        }

        @Override
        public String get(String key, String defaultValue) {
            final String value = this.get(key);
            return value == null ? defaultValue : value;
        }
    }
}