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Add ChronicleHashBuilder.averageKey() and ChronicleMapBuilder.averageValue() methods

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leventov
2015-07-29 01:21:21 +03:00
parent a3c9ed688c
commit e39dfc394c
7 changed files with 154 additions and 17 deletions
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src/main/java/net/openhft/chronicle/hash/ChronicleHashBuilder.java
+36 -1
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@@ -86,7 +86,8 @@ public interface ChronicleHashBuilder<K, H extends ChronicleHash<K, ?, ?, ?>,
/**
* Configures the average number of bytes, taken by serialized form of keys, put into hash
* containers, created by this builder. If key size is always the same, call {@link
* containers, created by this builder. However, in many cases {@link #averageKey(Object)} might
* be easier to use and more reliable. If key size is always the same, call {@link
* #constantKeySizeBySample(Object)} method instead of this one.
*
* <p>{@code ChronicleHashBuilder} implementation heuristically chooses
@@ -104,11 +105,43 @@ public interface ChronicleHashBuilder<K, H extends ChronicleHash<K, ?, ?, ?>,
* @throws IllegalStateException if key size is known statically and shouldn't be configured
* by user
* @throws IllegalArgumentException if the given {@code keySize} is non-positive
* @see #averageKey(Object)
* @see #constantKeySizeBySample(Object)
* @see #actualChunkSize(int)
*/
B averageKeySize(double averageKeySize);
/**
* Configures the average number of bytes, taken by serialized form of keys, put into hash
* containers, created by this builder, by serializing the given {@code averageKey} using
* the configured {@link #keyMarshallers(BytesWriter, BytesReader) keys marshallers}.
* In some cases, {@link #averageKeySize(double)} might be easier to use, than constructing the
* "average key". If key size is always the same, call {@link #constantKeySizeBySample(
* Object)} method instead of this one.
*
* <p>{@code ChronicleHashBuilder} implementation heuristically chooses
* {@linkplain #actualChunkSize(int) the actual chunk size} based on this configuration, that,
* however, might result to quite high internal fragmentation, i. e. losses because only
* integral number of chunks could be allocated for the entry. If you want to avoid this, you
* should manually configure the actual chunk size in addition to this average key size
* configuration, which is anyway needed.
*
* <p>If key is a boxed primitive type or {@link Byteable} subclass, i. e. if key size is known
* statically, it is automatically accounted and shouldn't be specified by user.
*
* <p>Calling this method clears any previous {@link #constantKeySizeBySample(Object)}
* configuration.
*
* @param averageKey the average (by footprint in serialized form) key, is going to be put
* into the hash containers, created by this builder
* @return this builder back
* @throws NullPointerException if the given {@code averageKey} is {@code null}
* @see #averageKeySize(double)
* @see #constantKeySizeBySample(Object)
* @see #actualChunkSize(int)
*/
B averageKey(K averageKey);
/**
* Configures the constant number of bytes, taken by serialized form of keys, put into hash
* containers, created by this builder. This is done by providing the {@code sampleKey}, all
@@ -120,6 +153,8 @@ public interface ChronicleHashBuilder<K, H extends ChronicleHash<K, ?, ?, ?>,
* <p>If key size varies, method {@link #averageKeySize(double)} should be called instead of
* this one.
*
* <p>Calling this method clears any previous {@link #averageKey(Object)} configuration.
*
* @param sampleKey the sample key
* @return this builder back
* @see #averageKeySize(double)