---
name: "ACE_Hash_Cache_Map_Manager"
section: "3"
platform: "linux"
package: "libace-doc"
version: "5.0.7-4"
release: "Debian 2.2 (Potato)"
platforms: ["linux"]
url: "https://new.carta.tech/ACE_Hash_Cache_Map_Manager"
---

# ACE\_Hash\_Cache\_Map\_Manager(3)

Defines a abstraction which will purge entries from a map. The map considered is the ACE\_Hash\_Map\_Manager\_Ex.

## NAME

ACE\_Hash\_Cache\_Map\_Manager -  Defines a abstraction which will purge entries from a map. The map considered is the ACE\_Hash\_Map\_Manager\_Ex.

## SYNOPSIS

```
#include <ace/Hash_Cache_Map_Manager.h>
template<class KEY, class VALUE, class HASH_KEY, class COMPARE_KEYS, class CACHING_STRATEGY, class ATTRIBUTES>
class ACE_Hash_Cache_Map_Manager : public ACE_CACHE_MAP_MANAGER
{
  public:
    typedef ACE_Pair<VALUE, ATTRIBUTES> CACHE_VALUE;
        typedef ACE_Hash_Map_Manager_Ex<KEY, CACHE_VALUE, HASH_KEY, COMPARE_KEYS, ACE_Null_Mutex> HASH_MAP;

    typedef ACE_Hash_Map_Entry<KEY, CACHE_VALUE> CACHE_ENTRY;
    typedef KEY key_type;
    typedef VALUE mapped_type;
    ACE_Hash_Cache_Map_Manager (
        CACHING_STRATEGY &caching_s,
        size_t size = ACE_DEFAULT_MAP_SIZE,
        ACE_Allocator *alloc = 0
        );
    ~ACE_Hash_Cache_Map_Manager (void);
    int bind (const KEY &key, const VALUE &value);
    int bind (
        const KEY &key,
        const VALUE &value,
        CACHE_ENTRY *&entry
        );
    int find (const KEY &key, VALUE &value);
    int find (const KEY &key);
    int find (const KEY &key, CACHE_ENTRY *&entry);
    int rebind (const KEY &key, const VALUE &value);
    int rebind (const KEY &key, const VALUE &value, VALUE &old_value);
    int rebind (
        const KEY &key,
        const VALUE &value,
        KEY &old_key,
        VALUE &old_value
        );
    int rebind (
        const KEY &key,
        const VALUE &value,
        CACHE_ENTRY *&entry
        );
    int trybind (const KEY &key, VALUE &value);
    int trybind (const KEY &key, VALUE &value, CACHE_ENTRY *&entry);
    int unbind (const KEY &key);
    int unbind (const KEY &key, VALUE &value);
    int unbind (CACHE_ENTRY *entry);
  protected:
    typedef ACE_CACHE_MAP_MANAGER ACE_HCMM_BASE;
};
```

## DESCRIPTION

The Hash\_Cache\_Map\_Manager will manage the map it contains and provide purging on demand from the map. The strategy for caching is decided by the user and provided to the Cache Manager.  The Cache Manager acts as a agent and communicates between the Map and the Strategy for purging entries from the map.  To tap the optimal methods like find(key,value,entry) present in the ACE\_Hash\_Map\_Manager, Hash\_Cache\_Map\_Manager provides extra functionality on top of the Cache\_Map\_Manager.

No locking mechanism provided since locking at this level isnt efficient.  Locking has to be provided by the application.

## Initialization and termination methods.

```
ACE_Hash_Cache_Map_Manager (
    CACHING_STRATEGY &caching_s,
    size_t size = ACE_DEFAULT_MAP_SIZE,
    ACE_Allocator *alloc = 0
    );
```

Initialize a Hash\_Cache\_Map\_Manager with size entries.

```
~ACE_Hash_Cache_Map_Manager (void);
```

Close down a Cache\_Map\_Manager and release dynamically allocated resources.

```
int bind (const KEY &key, const VALUE &value);
```

Associate key with value.  If key is already in the MAP then the ENTRY is not changed.  Returns 0 if a new entry is bound successfully, returns 1 if an attempt is made to bind an existing entry, and returns -1 if failures occur.

```
int bind (const KEY &key, const VALUE &value, CACHE_ENTRY *&entry);
```

Same as a normal bind, except the cache entry is also passed back to the caller.  The entry in this case will either be the newly created entry, or the existing one.

```
int find (const KEY &key, VALUE &value);
```

Loopkup entrykey,value in the cache.

```
int find (const KEY &key);
```

Is key in the cache?

```
int find (const KEY &key, CACHE_ENTRY *&entry);
```

Obtain the entry when the find succeeds.

```
int rebind (const KEY &key, const VALUE &value);
```

Reassociate the key with value. If the key already exists in the cache then returns 1, on a new bind returns 0 and returns -1 in case of any failures.

```
int rebind (const KEY &key, const VALUE &value, VALUE &old_value);
```

Reassociate key with value, storing the old value into the "out" parameter old\_value.  The function fails if key is not in the cache for caches that do not allow user specified keys. However, for caches that allow user specified keys, if the key is not in the cache, a new key/value association is created.

```
int rebind (
    const KEY &key,
    const VALUE &value,
    KEY &old_key,
    VALUE &old_value
    );
```

Reassociate key with value, storing the old key and value into the "out" parameters old\_key and old\_value.  The function fails if key is not in the cache for caches that do not allow user specified keys.  However, for caches that allow user specified keys, if the key is not in the cache, a new key/value association is created.

```
int rebind (const KEY &key, const VALUE &value, CACHE_ENTRY *&entry);
```

Same as a normal rebind, except the cache entry is also passed back to the caller.  The entry in this case will either be the newly created entry, or the existing one.

```
int trybind (const KEY &key, VALUE &value);
```

Associate key with value if and only if key is not in the cache.  If key is already in the cache, then the value parameter is overwritten with the existing value in the cache. Returns 0 if a new key/value association is created.  Returns 1 if an attempt is made to bind an existing entry.  This function fails for maps that do not allow user specified keys.

```
int trybind (const KEY &key, VALUE &value, CACHE_ENTRY *&entry);
```

Same as a normal trybind, except the cache entry is also passed back to the caller.  The entry in this case will either be the newly created entry, or the existing one.

```
int unbind (const KEY &key);
```

Remove key from the cache.

```
int unbind (const KEY &key, VALUE &value);
```

Remove key from the cache, and return the value associated with key.

```
int unbind (CACHE_ENTRY *entry);
```

Remove entry from map.

## AUTHOR

Kirthika Parameswaran kirthika@cs.wustl.edu

## LIBRARY

ace