org.apache.cayenne.util.concurrentlinkedhashmap

## Class ConcurrentLinkedHashMap.Builder<K,V>

- java.lang.Object
- - org.apache.cayenne.util.concurrentlinkedhashmap.ConcurrentLinkedHashMap.Builder<K,V>

- Enclosing class:
    ConcurrentLinkedHashMap<K,V>

      public static final class ConcurrentLinkedHashMap.Builder<K,V>
      extends Object

  A builder that creates `ConcurrentLinkedHashMap` instances. It provides a flexible approach for constructing customized instances with a named parameter syntax. It can be used in the following manner:

       {
           @code
           ConcurrentMap<Vertex, Set<Edge>> graph = new Builder<Vertex, Set<Edge>>()
                   .maximumWeightedCapacity(5000)
                   .weigher(Weighers.<Edge> set())
                   .build();
       }

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `Builder()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `ConcurrentLinkedHashMap<K,V>` | `build()` Creates a new `ConcurrentLinkedHashMap` instance.
    `ConcurrentLinkedHashMap.Builder<K,V>` | `catchup(ScheduledExecutorService executor, long delay, TimeUnit unit)` Specifies an executor for use in catching up the page replacement policy.
    `ConcurrentLinkedHashMap.Builder<K,V>` | `concurrencyLevel(int concurrencyLevel)` Specifies the estimated number of concurrently updating threads.
    `ConcurrentLinkedHashMap.Builder<K,V>` | `initialCapacity(int initialCapacity)` Specifies the initial capacity of the hash table (default `16`).
    `ConcurrentLinkedHashMap.Builder<K,V>` | `listener(org.apache.cayenne.util.concurrentlinkedhashmap.EvictionListener<K,V> listener)` Specifies an optional listener that is registered for notification when an entry is evicted.
    `ConcurrentLinkedHashMap.Builder<K,V>` | `maximumWeightedCapacity(int capacity)` Specifies the maximum weighted capacity to coerce the map to and may exceed it temporarily.
    `ConcurrentLinkedHashMap.Builder<K,V>` | `weigher(org.apache.cayenne.util.concurrentlinkedhashmap.Weigher<? super V> weigher)` Specifies an algorithm to determine how many the units of capacity a value consumes.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### Builder

          public Builder()

  - ### Method Detail

    - #### initialCapacity

          public ConcurrentLinkedHashMap.Builder<K,V> initialCapacity(int initialCapacity)

      Specifies the initial capacity of the hash table (default `16`). This is the number of key-value pairs that the hash table can hold before a resize operation is required.
      Parameters:
        `initialCapacity` - the initial capacity used to size the hash table to accommodate this many entries.
      Throws:
        `IllegalArgumentException` - if the initialCapacity is negative

    - #### maximumWeightedCapacity

          public ConcurrentLinkedHashMap.Builder<K,V> maximumWeightedCapacity(int capacity)

      Specifies the maximum weighted capacity to coerce the map to and may exceed it temporarily.
      Parameters:
        `capacity` - the weighted threshold to bound the map by
      Throws:
        `IllegalArgumentException` - if the maximumWeightedCapacity is negative

    - #### concurrencyLevel

          public ConcurrentLinkedHashMap.Builder<K,V> concurrencyLevel(int concurrencyLevel)

      Specifies the estimated number of concurrently updating threads. The implementation performs internal sizing to try to accommodate this many threads (default `16`).
      Parameters:
        `concurrencyLevel` - the estimated number of concurrently updating threads
      Throws:
        `IllegalArgumentException` - if the concurrencyLevel is less than or equal to zero

    - #### listener

          public ConcurrentLinkedHashMap.Builder<K,V> listener(org.apache.cayenne.util.concurrentlinkedhashmap.EvictionListener<K,V> listener)

      Specifies an optional listener that is registered for notification when an entry is evicted.
      Parameters:
        `listener` - the object to forward evicted entries to
      Throws:
        `NullPointerException` - if the listener is null

    - #### weigher

          public ConcurrentLinkedHashMap.Builder<K,V> weigher(org.apache.cayenne.util.concurrentlinkedhashmap.Weigher<? super V> weigher)

      Specifies an algorithm to determine how many the units of capacity a value consumes. The default algorithm bounds the map by the number of key-value pairs by giving each entry a weight of `1`.
      Parameters:
        `weigher` - the algorithm to determine a value's weight
      Throws:
        `NullPointerException` - if the weigher is null

    - #### catchup

          public ConcurrentLinkedHashMap.Builder<K,V> catchup(ScheduledExecutorService executor,
                                                              long delay,
                                                              TimeUnit unit)

      Specifies an executor for use in catching up the page replacement policy. The catch-up phase processes both updates to the retention ordering and writes that may trigger an eviction. The delay should be chosen carefully as the map will not automatically evict between executions.

      If unspecified or the executor is shutdown, the catching up will be amortized on user threads during write operations (or during read operations, in the absence of writes).

      A single-threaded `ScheduledExecutorService` should be sufficient for catching up the page replacement policy in many maps.

      Parameters:
        `executor` - the executor to schedule on
        `delay` - the delay between executions
        `unit` - the time unit of the delay parameter
      Throws:
        `NullPointerException` - if the executor or time unit is null
        `IllegalArgumentException` - if the delay is less than or equal to zero

    - #### build

          public ConcurrentLinkedHashMap<K,V> build()

      Creates a new `ConcurrentLinkedHashMap` instance.
      Throws:
        `IllegalStateException` - if the maximum weighted capacity was not set
        `RejectedExecutionException` - if an executor was specified and the catch-up task cannot be scheduled for execution

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