/
Accesses.java
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/
Accesses.java
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/*
* Copyright 2014 Higher Frequency Trading http://www.higherfrequencytrading.com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.openhft.chronicle.hash.hashing;
import net.openhft.lang.io.Bytes;
import java.nio.ByteBuffer;
/**
* Static methods returning useful {@link Access} implementations.
*/
public final class Accesses {
/**
* Returns the {@code Access} delegating {@code getXXX(input, offset)} methods to {@code
* sun.misc.Unsafe.getXXX(input, offset)}.
*
* <p>Usage example: <pre>{@code
* class Pair {
* long first, second;
*
* static final long pairDataOffset =
* theUnsafe.objectFieldOffset(Pair.class.getDeclaredField("first"));
*
* static long hashPair(Pair pair, LongHashFunction hashFunction) {
* return hashFunction.hash(pair, Accesses.unsafe(), pairDataOffset, 16L);
* }
* }}</pre>
*
* <p>{@code null} is a valid input, on accepting {@code null} {@code Unsafe} just interprets
* the given offset as a wild memory address.
*
* @param <T> the type of objects to access
* @return the unsafe memory {@code Access}
*/
public static <T> Access<T> unsafe() {
return (Access<T>) UnsafeAccess.INSTANCE;
}
/**
* Returns the {@code Access} to any {@link ByteBuffer}.
*
* @return the {@code Access} to {@link ByteBuffer}s
*/
public static Access<ByteBuffer> toByteBuffer() {
return ByteBufferAccess.INSTANCE;
}
public static Access<Bytes> toBytes() {
return BytesAccess.INSTANCE;
}
private Accesses() {}
}