import org.bitcoinj.wallet.listeners.WalletCoinsSentEventListener; //导入依赖的package包/类
protected void queueOnCoinsSent(final Transaction tx, final Coin prevBalance, final Coin newBalance) {
    checkState(lock.isHeldByCurrentThread());
    for (final ListenerRegistration<WalletCoinsSentEventListener> registration : coinsSentListeners) {
        registration.executor.execute(new Runnable() {
            @Override
            public void run() {
                registration.listener.onCoinsSent(Wallet.this, tx, prevBalance, newBalance);
            }
        });
    }
}
 

import org.bitcoinj.wallet.listeners.WalletCoinsSentEventListener; //导入依赖的package包/类
/**
 * Adds an event listener object called when coins are sent.
 * The listener is executed by the given executor.
 */
public void addCoinsSentEventListener(Executor executor, WalletCoinsSentEventListener listener) {
    // This is thread safe, so we don't need to take the lock.
    coinsSentListeners.add(new ListenerRegistration<>(listener, executor));
}
 

import org.bitcoinj.wallet.listeners.WalletCoinsSentEventListener; //导入依赖的package包/类
/**
 * Adds an event listener object called when coins are sent.
 * The listener is executed by the given executor.
 */
public void addCoinsSentEventListener(Executor executor, WalletCoinsSentEventListener listener) {
    // This is thread safe, so we don't need to take the lock.
    coinsSentListeners.add(new ListenerRegistration<WalletCoinsSentEventListener>(listener, executor));
}
 

import org.bitcoinj.wallet.listeners.WalletCoinsSentEventListener; //导入依赖的package包/类
/**
 * Removes the given event listener object. Returns true if the listener was removed, false if that listener
 * was never added.
 */
public boolean removeCoinsSentEventListener(WalletCoinsSentEventListener listener) {
    return ListenerRegistration.removeFromList(listener, coinsSentListeners);
}