Implement Permissions API

api/src/main/java/me/lokka30/treasury/api/permission/PermissionsProvider.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission;
+
+import java.util.Collection;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import me.lokka30.treasury.api.common.NamespacedKey;
+import me.lokka30.treasury.api.permission.node.holder.NodeHolderGroup;
+import me.lokka30.treasury.api.permission.node.holder.NodeHolderPlayer;
+import org.jetbrains.annotations.NotNull;
+
+public interface PermissionsProvider {
+
+    @NotNull CompletableFuture<NodeHolderPlayer> retrievePlayerNodeHolder(@NotNull UUID uuid);
+
+    @NotNull CompletableFuture<Collection<UUID>> allPlayerNodeHolderIds();
+
+    @NotNull CompletableFuture<NodeHolderGroup> retrieveOrCreateGroup(@NotNull NamespacedKey groupId);
+
+    @NotNull CompletableFuture<Collection<NamespacedKey>> allGroupNodeHolderIds();
+
+    @NotNull NodeHolderGroup defaultGroup();
+
+}

api/src/main/java/me/lokka30/treasury/api/permission/context/Context.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission.context;
+
+import java.util.Objects;
+import java.util.function.BiPredicate;
+import me.lokka30.treasury.api.common.NamespacedKey;
+import me.lokka30.treasury.api.permission.node.holder.NodeHolder;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Represents a context, in which a specific thing, a {@link me.lokka30.treasury.api.permission.node.Node} for example, applies.
+ *
+ * @author <a href="[email protected]">Ivan Pekov</a>
+ */
+public interface Context {
+
+    /**
+     * Returns the global context. If only this context is applied to a
+     * {@link me.lokka30.treasury.api.permission.node.Node} for example, that node will always
+     * apply without any other interference.
+     */
+    Context GLOBAL = Context.of(NamespacedKey.of("treasury", "global"), ($, $1) -> true);
+
+    /**
+     * Creates a new context.
+     *
+     * @param key       context key
+     * @param condition context condition
+     * @return new context
+     */
+    @Contract(value = "_, _ -> new", pure = true)
+    @NotNull
+    static Context of(
+            @NotNull NamespacedKey key, @NotNull BiPredicate<NodeHolder, String> condition
+    ) {
+        Objects.requireNonNull(key, "key");
+        Objects.requireNonNull(condition, "condition");
+        return new Context() {
+            @Override
+            public @NotNull NamespacedKey getKey() {
+                return key;
+            }
+
+            @Override
+            public @NotNull BiPredicate<NodeHolder, String> getCondition() {
+                return condition;
+            }
+        };
+    }
+
+    /**
+     * Returns the {@link NamespacedKey key} of this context.
+     *
+     * @return key
+     */
+    @NotNull NamespacedKey getKey();
+
+    /**
+     * Returns the condition under which this context will apply.
+     *
+     * @return condition
+     */
+    @NotNull BiPredicate<NodeHolder, String> getCondition();
+
+}

api/src/main/java/me/lokka30/treasury/api/permission/context/ContextSet.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission.context;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import me.lokka30.treasury.api.common.NamespacedKey;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Represents a set of {@link Context contexts}, which can be applied for a
+ * {@link me.lokka30.treasury.api.permission.node.Node}.
+ * <p>Class is immutable.
+ *
+ * @author <a href="mailto:[email protected]">Ivan Pekov</a>
+ */
+public final class ContextSet implements Iterable<Context> {
+
+    private static final ContextSet GLOBAL = new ContextSet(Collections.singletonMap(
+            Context.GLOBAL.getKey(),
+            Context.GLOBAL
+    ));
+    private static final ContextSet EMPTY = new ContextSet(Collections.emptyMap());
+
+    /**
+     * Returns the empty context set constant.
+     *
+     * @return empty context set
+     */
+    @NotNull
+    public static ContextSet empty() {
+        return EMPTY;
+    }
+
+    /**
+     * Returns the context set constant, which has only 1 context, and that is the
+     * {@link Context#GLOBAL global} context.
+     *
+     * @return global context set
+     */
+    @NotNull
+    public static ContextSet global() {
+        return GLOBAL;
+    }
+
+    /**
+     * Creates a new context set of the specified {@link Context contexts}
+     *
+     * @param contexts contexts the created context set will contain
+     * @return new context set
+     */
+    @NotNull
+    public static ContextSet of(@NotNull Context @NotNull ... contexts) {
+        Objects.requireNonNull(contexts, "contexts");
+        if (contexts.length == 0) {
+            return empty();
+        }
+        Map<NamespacedKey, Context> map = new ConcurrentHashMap<>();
+        for (Context context : contexts) {
+            map.put(context.getKey(), context);
+        }
+        return new ContextSet(map);
+    }
+
+    private Map<NamespacedKey, Context> contexts;
+
+    @Contract(pure = true)
+    private ContextSet(Map<NamespacedKey, Context> contexts) {
+        this.contexts = contexts;
+    }
+
+    /**
+     * Returns a {@link Optional}, which will be fulfilled with a {@link Context} if this context
+     * set holds a context, identified by the specified {@code contextKey}.
+     *
+     * @param contextKey context key
+     * @return context if such is found, empty optional otherwise
+     */
+    @NotNull
+    public Optional<Context> getContext(@NotNull NamespacedKey contextKey) {
+        Objects.requireNonNull(contextKey, "contextKey");
+        return Optional.ofNullable(this.contexts.get(contextKey));
+    }
+
+    /**
+     * Returns whether a {@link Context} is held under the specified {@code contextKey} in this
+     * context set.
+     *
+     * @param contextKey context key
+     * @return true if context is held, false otherwise
+     */
+    public boolean hasContext(@NotNull NamespacedKey contextKey) {
+        Objects.requireNonNull(contextKey, "contextKey");
+        return contexts.containsKey(contextKey);
+    }
+
+    /**
+     * Returns this context set as a mutable {@link Set}. Modifying the returned set will not
+     * affect the context set object this method is called from.
+     *
+     * @return set copy representation of this context set
+     */
+    @NotNull
+    public Set<Context> asSet() {
+        if (this.contexts.isEmpty()) {
+            return Collections.emptySet();
+        }
+        Set<Context> ret = ConcurrentHashMap.newKeySet();
+        ret.addAll(this.contexts.values());
+        return ret;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @NotNull
+    @Override
+    public Iterator<Context> iterator() {
+        Iterator<Context> handle = this.contexts.values().iterator();
+        // Iterator#remove default impl throws a UnsupportedOperationException which suits our needs
+        // we don't return this.contexts.values().iterator() directly as it is likely to have a
+        // remove() impl
+        return new Iterator<Context>() {
+            @Override
+            public boolean hasNext() {
+                return handle.hasNext();
+            }
+
+            // NotNull contract because per Iterator javadoc, Iterator#next throws
+            // NoSuchElementException if !hasNext() = true
+            @NotNull
+            @Override
+            public Context next() {
+                return handle.next();
+            }
+        };
+    }
+
+}

api/src/main/java/me/lokka30/treasury/api/permission/events/NodeEvent.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission.events;
+
+import me.lokka30.treasury.api.common.Cause;
+import me.lokka30.treasury.api.permission.node.Node;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+public class NodeEvent {
+
+    private Result result;
+
+    public NodeEvent(@NotNull Result initialResult) {
+        this.result = initialResult;
+    }
+
+    @NotNull
+    public Node getNode() {
+        return result.getNode();
+    }
+
+    @NotNull
+    public Cause<?> getCause() {
+        return result.getCause();
+    }
+
+    @NotNull
+    public Result asResult() {
+        return this.result;
+    }
+
+    public void withNewResult(@NotNull Result result) {
+        this.result = result;
+    }
+
+    public static class Result {
+
+        @NotNull
+        @Contract(value = "_, _ -> new", pure = true)
+        public static Result of(@NotNull Node node, @NotNull Cause<?> cause) {
+            return new Result(node, cause);
+        }
+
+        private final Node node;
+        private final Cause<?> cause;
+
+        private Result(@NotNull Node node, @NotNull Cause<?> cause) {
+            this.node = node;
+            this.cause = cause;
+        }
+
+        @NotNull
+        public Node getNode() {
+            return this.node;
+        }
+
+        @NotNull
+        public Cause<?> getCause() {
+            return this.cause;
+        }
+    }
+
+}

api/src/main/java/me/lokka30/treasury/api/permission/events/NodeRemoveEvent.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission.events;
+
+import me.lokka30.treasury.api.permission.node.holder.NodeHolder;
+import org.jetbrains.annotations.NotNull;
+
+public class NodeRemoveEvent extends NodeEvent {
+
+    private final NodeHolder nodeHolder;
+
+    public NodeRemoveEvent(
+            @NotNull NodeHolder nodeHolder, @NotNull NodeEvent.Result initialResult
+    ) {
+        super(initialResult);
+        this.nodeHolder = nodeHolder;
+    }
+
+    @NotNull
+    public NodeHolder getNodeHolder() {
+        return this.nodeHolder;
+    }
+
+}

api/src/main/java/me/lokka30/treasury/api/permission/events/NodeUpdateEvent.java

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+/*
+ * This file is/was part of Treasury. To read more information about Treasury such as its licensing, see <https://github.com/ArcanePlugins/Treasury>.
+ */
+
+package me.lokka30.treasury.api.permission.events;
+
+import me.lokka30.treasury.api.permission.node.holder.NodeHolder;
+import org.jetbrains.annotations.NotNull;
+
+public class NodeUpdateEvent extends NodeEvent {
+
+    private final NodeHolder nodeHolder;
+
+    public NodeUpdateEvent(
+            @NotNull NodeHolder nodeHolder, @NotNull NodeEvent.Result initialResult
+    ) {
+        super(initialResult);
+        this.nodeHolder = nodeHolder;
+    }
+
+    @NotNull
+    public NodeHolder getNodeHolder() {
+        return nodeHolder;
+    }
+
+}