## net.i2p.data
Class SDSCache<V extends SimpleDataStructure>

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

    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);
        }

Since:
  0.8.3
Author:
  zzz

Constructor Summary
`SDSCache(Class<V> rvClass, int len, int max)`

Method Summary
`V` `get(byte[] data)`
`V` `get(byte[] b, int off)`
`V` `get(InputStream in)`

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)

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

### get

    public V get(byte[] data)

  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
    `NPE`

### get

    public V get(byte[] b,
                 int off)

### get

    public V get(InputStream in)
                                      throws IOException

  Throws:
    `IOException`