SDSCache (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.i2p.data.SDSCache<V>

Type Parameters:: V - type of SimpleDataStructure objects cached

public class SDSCache<V extends SimpleDataStructure>
extends Object

A least recently used cache with a max size, for SimpleDataStructures. The index to the cache is the first 4 bytes of the data, so the data must be sufficiently random. This caches the SDS objects, and also uses SimpleByteCache to cache the unused byte arrays themselves Following is sample usage:


 private static final SDSCache< Foo> _cache = new SDSCache(Foo.class, LENGTH, 1024);

 public static Foo create(byte[] data) {
 return _cache.get(data);
 }

 public static Foo create(byte[] data, int off) {
 return _cache.get(data, off);
 }

 public static Foo create(InputStream in) throws IOException {
 return _cache.get(in);
 }

Constructor Summary
Constructors
Constructor and Description
SDSCache(Class<V> rvClass, int len, int max)
Class that we are storing, i.e.

Constructors
Constructor and Description
`SDSCache(Class<V> rvClass, int len, int max)` Class that we are storing, i.e.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Clear all entries from the cache.
`V`	`get(byte[] data)` WARNING - If the SDS is found in the cache, the passed-in byte array will be returned to the SimpleByteCache for reuse.
`V`	`get(byte[] b, int off)` Non-null byte array containing the data, data will be copied to not hold the reference.
`V`	`get(InputStream in)` Stream from which the bytes will be read.

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

- Constructor Detail
  - SDSCache
```
public SDSCache(Class<V> rvClass,
                int len,
                int max)
```
    Class that we are storing, i.e. an extension of SimpleDataStructure.
    Parameters:
    rvClass - the class that we are storing, i.e. an extension of SimpleDataStructure
    len - the length of the byte array in the SimpleDataStructure
    max - maximum size of the cache assuming 128MB of mem. The actual max size will be scaled based on available memory.
- Method Detail
  - clear
```
public void clear()
```
    Clear all entries from the cache.
  - get
```
public V get(byte[] data)
```
    WARNING - If the SDS is found in the cache, the passed-in byte array will be returned to the SimpleByteCache for reuse. Do NOT save a reference to the passed-in data, or use or modify it, after this call.
    Parameters:
    data - non-null, the byte array for the SimpleDataStructure
    Returns:
    the cached value if available, otherwise makes a new object and returns it
    Throws:
    IllegalArgumentException - if data is not the correct number of bytes
    NullPointerException - if data is null
  - get
```
public V get(byte[] b,
             int off)
```
    Non-null byte array containing the data, data will be copied to not hold the reference.
    Parameters:
    b - non-null byte array containing the data, data will be copied to not hold the reference
    off - offset in the array to start reading from
    Returns:
    the cached value if available, otherwise makes a new object and returns it
    Throws:
    ArrayIndexOutOfBoundsException - if not enough bytes
    NullPointerException
  - get
```
public V get(InputStream in)
      throws IOException
```
    Stream from which the bytes will be read.
    Parameters:
    in - a stream from which the bytes will be read
    Returns:
    the cached value if available, otherwise makes a new object and returns it
    Throws:
    IOException - if not enough bytes

Class SDSCache<V extends SimpleDataStructure>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SDSCache

Method Detail

clear

get

get

get