com.artipie.composer.JsonPackage Maven / Gradle / Ivy

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/*
 * The MIT License (MIT) Copyright (c) 2020-2023 artipie.com
 * https://github.com/artipie/artipie/blob/master/LICENSE.txt
 */
package com.artipie.composer;

import java.io.StringReader;
import java.nio.charset.StandardCharsets;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import javax.json.Json;
import javax.json.JsonObject;
import javax.json.JsonReader;

/**
 * PHP Composer package built from JSON.
 *
 * @since 0.1
 */
public final class JsonPackage implements Package {
    /**
     * Key for version in JSON.
     */
    public static final String VRSN = "version";

    /**
     * Package binary content.
     */
    private final JsonObject json;

    /**
     * Ctor.
     *
     * @param data Package binary content.
     */
    public JsonPackage(final byte[] data) {
        this(JsonPackage.loadJson(data));
    }

    /**
     * Ctor.
     *
     * @param json Package json content.
     */
    public JsonPackage(final JsonObject json) {
        this.json = json;
    }

    @Override
    public CompletionStage name() {
        return this.mandatoryString("name")
            .thenApply(Name::new);
    }

    @Override
    public CompletionStage> version(final Optional value) {
        final String version = value.orElse(null);
        return this.optString(JsonPackage.VRSN)
            .thenApply(opt -> opt.orElse(version))
            .thenApply(Optional::ofNullable);
    }

    @Override
    public CompletionStage json() {
        return CompletableFuture.completedFuture(this.json);
    }

    /**
     * Load JsonObject from binary data.
     * @param data Json object content.
     * @return JsonObject instance.
     */
    private static JsonObject loadJson(final byte[] data) {
        try (JsonReader reader = Json.createReader(
            new StringReader(new String(data, StandardCharsets.UTF_8))
        )) {
            return reader.readObject();
        }
    }

    /**
     * Reads string value from package JSON root. Throws exception if value not found.
     *
     * @param name Attribute value.
     * @return String value.
     */
    private CompletionStage mandatoryString(final String name) {
        return this.json()
            .thenApply(jsn -> jsn.getString(name))
            .thenCompose(
                val -> {
                    final CompletionStage res;
                    if (val == null) {
                        res = new CompletableFuture()
                            .exceptionally(
                                ignore -> {
                                    throw new IllegalStateException(
                                        String.format("Bad package, no '%s' found.", name)
                                    );
                                }
                        );
                    } else {
                        res = CompletableFuture.completedFuture(val);
                    }
                    return res;
                }
            );
    }

    /**
     * Reads string value from package JSON root. Empty in case of absence.
     * @param name Attribute value
     * @return String value, otherwise empty.
     */
    private CompletionStage> optString(final String name) {
        return this.json()
            .thenApply(json -> json.getString(name, null))
            .thenApply(Optional::ofNullable);
    }
}