/** Standard constructor. */
  protected AbstractMapBasedMultiset(Map<E, Count> backingMap) {
    checkArgument(backingMap.isEmpty());
    this.backingMap = backingMap;
  }

  /** Used during deserialization only. The backing map must be empty. */
  void setBackingMap(Map<E, Count> backingMap) {
    this.backingMap = backingMap;
  }

  // Required Implementations

  /**
   * {@inheritDoc}
   *

书接上文，多个关联模型这种情况很常见。

特别是用户模型，因为：

* **输入模型**应该含密码
* **输出模型**不应含密码
* **数据库模型**需要加密的密码

/// danger | "危险"

千万不要存储用户的明文密码。始终存储可以进行验证的**安全哈希值**。

如果不了解这方面的知识，请参阅[安全性中的章节](security/simple-oauth2.md#password-hashing){.internal-link target=_blank}，了解什么是**密码哈希**。

///

## 多个模型

下面的代码展示了不同模型处理密码字段的方式，及使用位置的大致思路：

//// tab | Python 3.10+

```Python hl_lines="7  9  14  20  22  27-28  31-33  38-39"

 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
```

## Start MinIO with Lambda target

Register MinIO with a Lambda function, we are calling our target name as `function`, but you may call it any other friendly name of your choice.
```
MINIO_LAMBDA_WEBHOOK_ENABLE_function=on MINIO_LAMBDA_WEBHOOK_ENDPOINT_function=http://localhost:5000 minio server /data &
...
...

   * updates are made to the base field.  Upon first contention (a
   * failed CAS on base update), the table is initialized to size 2.
   * The table size is doubled upon further contention until
   * reaching the nearest power of two greater than or equal to the
   * number of CPUS. Table slots remain empty (null) until they are
   * needed.
   *
   * A single spinlock ("busy") is used for initializing and

  // URLClassLoader without capturing this reference, and it probably would not be desirable for
  // security reasons anyway. Therefore, the FRQ.close() method provides a way to stop the thread
  // explicitly. This test checks that calling that method does allow an app's ClassLoader to be
  // gc'd even if there is a still a FinalizableReferenceQueue in a static field. (Setting the field

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link Maps#transformValues} when the backing map's views have iterators that don't
 * support {@code remove()}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

  private DiscreteDomain(boolean supportsFastOffset) {
    this.supportsFastOffset = supportsFastOffset;
  }

  /**
   * Returns, conceptually, "origin + distance", or equivalently, the result of calling {@link
   * #next} on {@code origin} {@code distance} times.
   */
  C offset(C origin, long distance) {
    C current = origin;
    checkNonnegative(distance, "distance");
    for (long i = 0; i < distance; i++) {

      function = null;
    }

    /*
     * If set()/setValue() throws an Error, we let it propagate. Why? The most likely Error is a
     * StackOverflowError (from deep transform(..., directExecutor()) nesting), and calling
     * setException(stackOverflowError) would fail:
     *
     * - If the stack overflowed before set()/setValue() could even store the result in the output

        // padding is alwas binary 1 followed by binary 0s
        byte[] tail = new byte[padLen + 8];
        tail[0] = (byte)0x80;

        // append length before final transform:
        // save number of bits, casting the long to an array of 8 bytes
        // save low-order byte first.
        for (int i = 0; i < 8; i++)
            tail[padLen + i] = (byte)((count * 8) >>> (8 * i));

        engineUpdate(tail, 0, tail.length);

// until [Next] is called to advance to the next file.
//
// If the current file is sparse, then the regions marked as a hole
// are read back as NUL-bytes.
//
// Calling Read on special types like [TypeLink], [TypeSymlink], [TypeChar],
// [TypeBlock], [TypeDir], and [TypeFifo] returns (0, [io.EOF]) regardless of what
// the [Header.Size] claims.
func (tr *Reader) Read(b []byte) (int, error) {