Added new permission system

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/permissions/PermissionAttachment.java

@@ -0,0 +1,134 @@
+
+package org.bukkit.permissions;
+
+import java.util.Map;
+import java.util.TreeMap;
+import org.bukkit.plugin.Plugin;
+
+/**
+ * Holds information about a permission attachment on a {@link Permissible} object
+ */
+public class PermissionAttachment {
+    private PermissionRemovedExecutor removed;
+    private final TreeMap<String, Boolean> permissions = new TreeMap<String, Boolean>();
+    private final Permissible permissible;
+    private final Plugin plugin;
+
+    public PermissionAttachment(Plugin plugin, Permissible Permissible) {
+        if (plugin == null) {
+            throw new IllegalArgumentException("Plugin cannot be null");
+        } else if (!plugin.isEnabled()) {
+            throw new IllegalArgumentException("Plugin " + plugin.getDescription().getFullName() + " is disabled");
+        }
+
+        this.permissible = Permissible;
+        this.plugin = plugin;
+    }
+
+    /**
+     * Gets the plugin responsible for this attachment
+     *
+     * @return Plugin responsible for this permission attachment
+     */
+    public Plugin getPlugin() {
+        return plugin;
+    }
+
+    /**
+     * Sets an object to be called for when this attachment is removed from a {@link Permissible}. May be null.
+     *
+     * @param ex Object to be called when this is removed
+     */
+    public void setRemovalCallback(PermissionRemovedExecutor ex) {
+        removed = ex;
+    }
+
+    /**
+     * Gets the class that was previously set to be called when this attachment was removed from a {@link Permissible}. May be null.
+     *
+     * @return Object to be called when this is removed
+     */
+    public PermissionRemovedExecutor getRemovalCallback() {
+        return removed;
+    }
+
+    /**
+     * Gets the Permissible that this is attached to
+     *
+     * @return Permissible containing this attachment
+     */
+    public Permissible getPermissible() {
+        return permissible;
+    }
+
+    /**
+     * Gets a copy of all set permissions and values contained within this attachment.
+     *
+     * This map may be modified but will not affect the attachment, as it is a copy.
+     *
+     * @return Copy of all permissions and values expressed by this attachment
+     */
+    public Map<String, Boolean> getPermissions() {
+        return (Map<String, Boolean>)permissions.clone();
+    }
+
+    /**
+     * Sets a permission to the given value, by its fully qualified name
+     *
+     * @param name Name of the permission
+     * @param value New value of the permission
+     */
+    public void setPermission(String name, boolean value) {
+        permissions.put(name.toLowerCase(), value);
+        permissible.recalculatePermissions();
+    }
+
+    /**
+     * Sets a permission to the given value
+     *
+     * @param perm Permission to set
+     * @param value New value of the permission
+     */
+    public void setPermission(Permission perm, boolean value) {
+        setPermission(perm.getName(), value);
+        permissible.recalculatePermissions();
+    }
+
+    /**
+     * Removes the specified permission from this attachment.
+     *
+     * If the permission does not exist in this attachment, nothing will happen.
+     *
+     * @param name Name of the permission to remove
+     */
+    public void unsetPermission(String name) {
+        permissions.remove(name.toLowerCase());
+        permissible.recalculatePermissions();
+    }
+
+    /**
+     * Removes the specified permission from this attachment.
+     *
+     * If the permission does not exist in this attachment, nothing will happen.
+     *
+     * @param perm Permission to remove
+     */
+    public void unsetPermission(Permission perm) {
+        unsetPermission(perm.getName());
+        permissible.recalculatePermissions();
+    }
+
+    /**
+     * Removes this attachment from its registered {@link Permissible}
+     *
+     * @return true if the permissible was removed successfully, false if it did not exist
+     */
+    public boolean remove() {
+        try {
+            permissible.removeAttachment(this);
+            return true;
+        } catch (IllegalArgumentException ex) {
+            return false;
+        }
+    }
+}