Economy v2.

New methods include:

- UUID-focused methods replacing the Name and OfflinePlayer methods.

- getUUIDNameMap() which makes the economy plugin able to supply a Map
of UUIDs and last-known-names on request. This will be used to replace
the code in Vault which converts between economy plugins (and is
currently only able to convert accounts belonging to players which have
logged in.) The @nullable annotation is used here in order to declare
that the last-known-name of the account is allowed to be null.

- getAccountName(UUID) which will return the last-known-name of an
account or null.

Other Changes:

- Minor changes to javadocs.

src/main/java/net/milkbowl/vault2/economy/Economy.java

@@ -0,0 +1,322 @@
+/* This file is part of Vault.
+
+    Vault is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Vault is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with Vault.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.milkbowl.vault2.economy;
+
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * The main economy API
+ *
+ */
+public interface Economy {
+
+    /*
+     * Economy plugin-related methods follow. 
+     */
+
+    /**
+     * Checks if economy plugin is enabled.
+     * 
+     * @return Success or Failure
+     */
+    public boolean isEnabled();
+
+    /**
+     * Gets name of economy plugin.
+     * 
+     * @return Name of Economy plugin.
+     */
+    public String getName();
+
+    /**
+     * Returns true if the given implementation supports banks.
+     * 
+     * @return true if the implementation supports banks
+     */
+    public boolean hasBankSupport();
+
+    /*
+     * Currency-related methods follow.
+     */
+
+    /**
+     * Some economy plugins round off after a certain number of digits. This
+     * function returns the number of digits the plugin keeps or -1 if no rounding
+     * occurs.
+     * 
+     * @return number of digits after the decimal point kept
+     */
+    public int fractionalDigits();
+
+    /**
+     * Format amount into a human readable String This provides translation into
+     * economy specific formatting to improve consistency between plugins.
+     *
+     * @param amount to format
+     * @return Human readable string describing amount
+     */
+    public String format(double amount);
+
+    /**
+     * Returns the name of the currency in plural form. If the economy being used
+     * does not support currency names then an empty string will be returned.
+     * 
+     * @return name of the currency (plural)
+     */
+    public String currencyNamePlural();
+
+    /**
+     * Returns the name of the currency in singular form. If the economy being used
+     * does not support currency names then an empty string will be returned.
+     * 
+     * @return name of the currency (singular)
+     */
+    public String currencyNameSingular();
+
+    /*
+     * Account-related methods follow.
+     */
+
+    /**
+     * Attempts to create a account for the given uuid
+     * 
+     * @param uuid associated with the account
+     * @return if the account creation was successful
+     */
+    public boolean createAccount(UUID uuid);
+
+    /**
+     * Attempts to create an account for the given UUID on the specified world
+     * IMPLEMENTATION SPECIFIC - if an economy plugin does not support this then
+     * false will always be returned.
+     * 
+     * @param uuid      associated with the account
+     * @param worldName String name of the world
+     * @return if the account creation was successful
+     */
+    public boolean createAccount(UUID uuid, String worldName);
+
+    /**
+     * Returns a map that represents all of the UUIDs which have accounts in the
+     * plugin, as well as their last-known-name whether it is null or not. This is
+     * used for Vault's economy converter and should be given every account
+     * available.
+     * 
+     * @return a {@link Map} composed of the accounts keyed by their UUID, along
+     *         with their associated last-known-name (null or not.)
+     */
+    public Map<UUID, @Nullable String> getUUIDNameMap();
+
+    /**
+     * Gets the last known name of an account owned by the given UUID. Required for
+     * messages to be more human-readable than UUIDs alone can provide.
+     * 
+     * @param uuid UUID to look up.
+     * @return name of the account owner or null.
+     */
+    @Nullable
+    public String getAccountName(UUID uuid);
+
+    /**
+     * Checks if this uuid has an account yet
+     * 
+     * @param uuid to check
+     * @return if the uuid has an account
+     */
+    public boolean hasAccount(UUID uuid);
+
+    /**
+     * Checks if this uuid has an account yet on the given world
+     * 
+     * @param uuid      to check
+     * @param worldName world-specific account
+     * @return if the uuid has an account
+     */
+    public boolean hasAccount(UUID uuid, String worldName);
+
+    /**
+     * Gets balance of a UUID
+     * 
+     * @param uuid of the account to get a balance for
+     * @return Amount currently held in account associated with the given UUID
+     */
+    public double getBalance(UUID uuid);
+
+    /**
+     * Gets balance of a UUID on the specified world. IMPLEMENTATION SPECIFIC - if
+     * an economy plugin does not support this the global balance will be returned.
+     * 
+     * @param uuid  of the account to get a balance for
+     * @param world name of the world
+     * @return Amount currently held in account associated with the given UUID
+     */
+    public double getBalance(UUID uuid, String world);
+
+    /**
+     * Checks if the account associated with the given UUID has the amount - DO NOT
+     * USE NEGATIVE AMOUNTS
+     * 
+     * @param uuid   to check
+     * @param amount to check for
+     * @return True if <b>UUID</b> has <b>amount</b>, False else wise
+     */
+    public boolean has(UUID uuid, double amount);
+
+    /**
+     * Checks if the account associated with the given UUID has the amount in the
+     * given world - DO NOT USE NEGATIVE AMOUNTS IMPLEMENTATION SPECIFIC - if an
+     * economy plugin does not support this the global balance will be returned.
+     * 
+     * @param uuid      to check
+     * @param worldName to check with
+     * @param amount    to check for
+     * @return True if <b>UUID</b> has <b>amount</b> in the given <b>world</b>,
+     *         False else wise
+     */
+    public boolean has(UUID uuid, String worldName, double amount);
+
+    /**
+     * Withdraw an amount from an account associated with a UUID - DO NOT USE
+     * NEGATIVE AMOUNTS
+     * 
+     * @param uuid   to withdraw from
+     * @param amount Amount to withdraw
+     * @return Detailed response of transaction
+     */
+    public EconomyResponse withdraw(UUID uuid, double amount);
+
+    /**
+     * Withdraw an amount from an account associated with a UUID on a given world -
+     * DO NOT USE NEGATIVE AMOUNTS IMPLEMENTATION SPECIFIC - if an economy plugin
+     * does not support this the global balance will be returned.
+     * 
+     * @param uuid      to withdraw from
+     * @param worldName - name of the world
+     * @param amount    Amount to withdraw
+     * @return Detailed response of transaction
+     */
+    public EconomyResponse withdraw(UUID uuid, String worldName, double amount);
+
+    /**
+     * Deposit an amount to an account associated with the given UUID - DO NOT USE
+     * NEGATIVE AMOUNTS
+     * 
+     * @param uuid   to deposit to
+     * @param amount Amount to deposit
+     * @return Detailed response of transaction
+     */
+    public EconomyResponse deposit(UUID uuid, double amount);
+
+    /**
+     * Deposit an amount from an account associated with a UUID on a given world -
+     * DO NOT USE NEGATIVE AMOUNTS IMPLEMENTATION SPECIFIC - if an economy plugin
+     * does not support this the global balance will be returned.
+     * 
+     * @param uuid      to deposit to
+     * @param worldName name of the world
+     * @param amount    Amount to deposit
+     * @return Detailed response of transaction
+     */
+    public EconomyResponse deposit(UUID uuid, String worldName, double amount);
+
+    /*
+     * Bank methods follow.
+     */
+
+    /**
+     * Creates a bank account with the specified name and the given UUID as the
+     * owner
+     * 
+     * @param name of account
+     * @param uuid the account should be linked to
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse createBank(String name, UUID uuid);
+
+    /**
+     * Deletes a bank account with the specified name.
+     * 
+     * @param name of the back to delete
+     * @return if the operation completed successfully
+     */
+    public EconomyResponse deleteBank(String name);
+
+    /**
+     * Returns the amount the bank has
+     * 
+     * @param name of the account
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse bankBalance(String name);
+
+    /**
+     * Returns true or false whether the bank has the amount specified - DO NOT USE
+     * NEGATIVE AMOUNTS
+     * 
+     * @param name   of the account
+     * @param amount to check for
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse bankHas(String name, double amount);
+
+    /**
+     * Withdraw an amount from a bank account - DO NOT USE NEGATIVE AMOUNTS
+     * 
+     * @param name   of the account
+     * @param amount to withdraw
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse bankWithdraw(String name, double amount);
+
+    /**
+     * Deposit an amount into a bank account - DO NOT USE NEGATIVE AMOUNTS
+     * 
+     * @param name   of the account
+     * @param amount to deposit
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse bankDeposit(String name, double amount);
+
+    /**
+     * Check if a uuid is the owner of a bank account
+     * 
+     * @param name of the account
+     * @param uuid to check for ownership
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse isBankOwner(String name, UUID uuid);
+
+    /**
+     * Check if the uuid is a member of the bank account
+     * 
+     * @param name of the account
+     * @param uuid to check membership
+     * @return EconomyResponse Object
+     */
+    public EconomyResponse isBankMember(String name, UUID uuid);
+
+    /**
+     * Gets the list of banks
+     * 
+     * @return the List of Banks
+     */
+    public List<String> getBanks();
+}