/**
* Specifies the weigher to use in determining the weight of entries. Entry weight is taken into
* consideration by {@link #maximumWeight(long)} when determining which entries to evict, and use
* of this method requires a corresponding call to {@link #maximumWeight(long)} prior to calling
* {@link #build}. Weights are measured and recorded when entries are inserted into the cache, and
* are thus effectively static during the lifetime of a cache entry.
*
* <p>When the weight of an entry is zero it will not be considered for size-based eviction
* (though it still may be evicted by other means).
*
* <p><b>Important note:</b> Instead of returning <em>this</em> as a {@code CacheBuilder}
* instance, this method returns {@code CacheBuilder<K1, V1>}. From this point on, either the
* original reference or the returned reference may be used to complete configuration and build
* the cache, but only the "generic" one is type-safe. That is, it will properly prevent you from
* building caches whose key or value types are incompatible with the types accepted by the
* weigher already provided; the {@code CacheBuilder} type cannot do this. For best results,
* simply use the standard method-chaining idiom, as illustrated in the documentation at top,
* configuring a {@code CacheBuilder} and building your {@link Cache} all in a single statement.
*
* <p><b>Warning:</b> if you ignore the above advice, and use this {@code CacheBuilder} to build a
* cache whose key or value type is incompatible with the weigher, you will likely experience a
* {@link ClassCastException} at some <i>undefined</i> point in the future.
*
* @param weigher the weigher to use in calculating the weight of cache entries
* @return this {@code CacheBuilder} instance (for chaining)
* @throws IllegalArgumentException if {@code size} is negative
* @throws IllegalStateException if a maximum size was already set
* @since 11.0
*/
@GwtIncompatible // To be supported
public <K1 extends K, V1 extends V> CacheBuilder<K1, V1> weigher(
Weigher<? super K1, ? super V1> weigher) {
checkState(this.weigher == null);
if (strictParsing) {
checkState(
this.maximumSize == UNSET_INT,
"weigher can not be combined with maximum size",
this.maximumSize);
}
// safely limiting the kinds of caches this can produce
@SuppressWarnings("unchecked")
CacheBuilder<K1, V1> me = (CacheBuilder<K1, V1>) this;
me.weigher = checkNotNull(weigher);
return me;
}
public <K1, V1> com.google.common.cache.CacheBuilder<K1, V1> weigher(
Weigher<? super K1, ? super V1> weigher) {
return builder.weigher(weigher);
}