TLcdCache (LuciadLightspeed API documentation)

java.lang.Object
- com.luciad.util.TLcdCache

All Implemented Interfaces:

ILcdCache
```
public class TLcdCache
extends Object
implements ILcdCache
```
Implementation of ILcdCache. By default, it automatically removes cached key-value pairs that are no longer used. It does so by using WeakReferences to refer the keys. This means that if the key is no longer strongly reachable, and therefore set to null by the garbage collector, the value will be removed from the TLcdCache on the next access. This is particularly useful if some long term object such as an ILcdGXYPainter or an ILcdGXYLayer is used as a key: when the object is garbage collected, the cached values will be removed automatically.
The values are however not weakly referenced, so care must be taken that no (indirect) strong reference exists from the value to the key. If such a strong reference from the value to the key exists, it will prevent the key from being weakly reachable, and therefore the key-value pair may never be removed automatically.
The weak behavior can be turned off, by either setting setUseWeakKeyReferences(boolean) to false, or by passing false to TLcdCache(boolean).
Values are softly referenced by default, and hence may be garbage collected when memory needs to be reclaimed.
Please refer to java.util.ref for definitions of 'strongly reachable', 'weakly reachable', WeakReference etc.

Constructor Summary

Constructors
Constructor and Description
`TLcdCache()` Creates a new `TLcdCache` instance.
`TLcdCache(boolean aUseWeakKeyReferences)` Creates a new `TLcdCache` instance.
`TLcdCache(boolean aUseWeakKeyReferences, boolean aUseSoftValueReferences)` Creates a new `TLcdCache` instance.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clearCache()` Clears the cache.
`Object`	`getCachedObject(Object aKey)` Looks up and returns the cached Object corresponding to the given key.
`void`	`insertIntoCache(Object aKey, Object aValue)` Inserts a cache Object corresponding to the given key Object.
`static boolean`	`isUseSoftValueReferences()` Returns true if soft references for the values are used.
`static boolean`	`isUseWeakKeyReferences()` Returns true if weak references for the keys are used.
`Object`	`removeCachedObject(Object aKey)` Looks up and removes the cached Object corresponding to the given key.
`static void`	`setUseSoftValueReferences(boolean aUseSoftValueReferences)` Sets if soft references for the values are used.
`static void`	`setUseWeakKeyReferences(boolean aUseWeakKeyReferences)` Sets if weak references for the keys are used.
`int`	`size()` Returns the amount of key-value pairs in this `TLcdCache` object.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - TLcdCache
```
public TLcdCache()
```
    Creates a new TLcdCache instance. It refers the keys weakly if isUseWeakKeyReferences() returns true. It refers the values softly if isUseSoftValueReferences() returns true. Please refer to TLcdCache for more information on the handling of keys and values.
  - TLcdCache
```
public TLcdCache(boolean aUseWeakKeyReferences)
```
    Creates a new TLcdCache instance. It refers the values softly if isUseSoftValueReferences() returns true.
    
    Parameters:
    
    aUseWeakKeyReferences - True if the keys should be referred weakly, false otherwise. Please refer to TLcdCache for more information on the handling of keys and values.
  - TLcdCache
```
public TLcdCache(boolean aUseWeakKeyReferences,
                 boolean aUseSoftValueReferences)
```
    Creates a new TLcdCache instance.
    
    Parameters:
    
    aUseWeakKeyReferences - True if the keys should be referred weakly, false otherwise.
    
    aUseSoftValueReferences - True if the values should be referred softly, false otherwise. Please refer to TLcdCache for more information on the handling of keys and values.
- Method Detail
  - isUseWeakKeyReferences
```
public static boolean isUseWeakKeyReferences()
```
    Returns true if weak references for the keys are used. The default is true.
    
    Returns:
    
    true if weak references for the keys are used.
    
    See Also:
    
    TLcdCache()
  - setUseWeakKeyReferences
```
public static void setUseWeakKeyReferences(boolean aUseWeakKeyReferences)
```
    Sets if weak references for the keys are used.
    This property can also be set by assigning 'true' or 'false' to the system property 'com.luciad.util.TLcdCache.useWeakKeyReferences'. A system property can be set using the command line option -Dkey=value to java.
    
    Parameters:
    
    aUseWeakKeyReferences - True to allow weak references for the keys, false otherwise.
    
    See Also:
    
    TLcdCache()
  - isUseSoftValueReferences
```
public static boolean isUseSoftValueReferences()
```
    Returns true if soft references for the values are used. The default is true.
    
    Returns:
    
    true if soft references for the values are used.
  - setUseSoftValueReferences
```
public static void setUseSoftValueReferences(boolean aUseSoftValueReferences)
```
    Sets if soft references for the values are used.
    This property can also be set by assigning 'true' or 'false' to the system property 'com.luciad.util.TLcdCache.useSoftValueReferences'. A system property can be set using the command line option -Dkey=value to java.
    
    Parameters:
    
    aUseSoftValueReferences - True to allow soft references for the values, false otherwise.
  - size
```
public int size()
```
    Returns the amount of key-value pairs in this TLcdCache object.
    
    Returns:
    
    the amount of key-value pairs in this TLcdCache object.
  - insertIntoCache
```
public void insertIntoCache(Object aKey,
                            Object aValue)
```
    Description copied from interface: ILcdCache
    
    Inserts a cache Object corresponding to the given key Object.
    
    Specified by:
    
    insertIntoCache in interface ILcdCache
    
    Parameters:
    
    aKey - the key Object that will be used to identify the Object. The key must therefore be a unique identifier, typically the caller itself: insertIntoCache(this, ...).
    
    aValue - the Object to be cached.
  - removeCachedObject
```
public Object removeCachedObject(Object aKey)
```
    Description copied from interface: ILcdCache
    
    Looks up and removes the cached Object corresponding to the given key.
    
    Specified by:
    
    removeCachedObject in interface ILcdCache
    
    Parameters:
    
    aKey - the key Object that was used for storing the cache Object.
    
    Returns:
    
    the cached Object, or null if there was no Object corresponding to the given key.
  - clearCache
```
public void clearCache()
```
    Description copied from interface: ILcdCache
    
    Clears the cache.
    
    Specified by:
    
    clearCache in interface ILcdCache
  - getCachedObject
```
public Object getCachedObject(Object aKey)
```
    Description copied from interface: ILcdCache
    
    Looks up and returns the cached Object corresponding to the given key.
    
    Specified by:
    
    getCachedObject in interface ILcdCache
    
    Parameters:
    
    aKey - the key Object that was used for storing the cache Object.
    
    Returns:
    
    the cached Object, or null if there is no Object corresponding to the given key.

LuciadLightspeedClass TLcdCache

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

TLcdCache

TLcdCache

TLcdCache

Method Detail

isUseWeakKeyReferences

setUseWeakKeyReferences

isUseSoftValueReferences

setUseSoftValueReferences

size

insertIntoCache

removeCachedObject

clearCache

getCachedObject