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Core sketch algorithms used alone and by other Java repositories in the DataSketches library.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.datasketches.theta;
import static org.apache.datasketches.common.Family.idToFamily;
import static org.apache.datasketches.common.Util.ceilingIntPowerOf2;
import static org.apache.datasketches.theta.PreambleUtil.FAMILY_BYTE;
import static org.apache.datasketches.theta.PreambleUtil.SER_VER_BYTE;
import org.apache.datasketches.common.Family;
import org.apache.datasketches.common.SketchesArgumentException;
import org.apache.datasketches.memory.Memory;
import org.apache.datasketches.memory.WritableMemory;
import org.apache.datasketches.thetacommon.ThetaUtil;
/**
* The parent API for all Set Operations
*
* @author Lee Rhodes
*/
public abstract class SetOperation {
static final int CONST_PREAMBLE_LONGS = 3;
SetOperation() {}
/**
* Makes a new builder
*
* @return a new builder
*/
public static final SetOperationBuilder builder() {
return new SetOperationBuilder();
}
/**
* Heapify takes the SetOperations image in Memory and instantiates an on-heap
* SetOperation using the
* Default Update Seed.
* The resulting SetOperation will not retain any link to the source Memory.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* heapified.
*
* @param srcMem an image of a SetOperation where the image seed hash matches the default seed hash.
* See Memory
* @return a Heap-based SetOperation from the given Memory
*/
public static SetOperation heapify(final Memory srcMem) {
return heapify(srcMem, ThetaUtil.DEFAULT_UPDATE_SEED);
}
/**
* Heapify takes the SetOperation image in Memory and instantiates an on-heap
* SetOperation using the given expectedSeed.
* The resulting SetOperation will not retain any link to the source Memory.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* heapified.
*
* @param srcMem an image of a SetOperation where the hash of the given expectedSeed matches the image seed hash.
* See Memory
* @param expectedSeed the seed used to validate the given Memory image.
* See Update Hash Seed.
* @return a Heap-based SetOperation from the given Memory
*/
public static SetOperation heapify(final Memory srcMem, final long expectedSeed) {
final byte famID = srcMem.getByte(FAMILY_BYTE);
final Family family = idToFamily(famID);
switch (family) {
case UNION : {
return UnionImpl.heapifyInstance(srcMem, expectedSeed);
}
case INTERSECTION : {
return IntersectionImpl.heapifyInstance(srcMem, expectedSeed);
}
default: {
throw new SketchesArgumentException("SetOperation cannot heapify family: "
+ family.toString());
}
}
}
/**
* Wrap takes the SetOperation image in Memory and refers to it directly.
* There is no data copying onto the java heap.
* This method assumes the
* Default Update Seed.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* wrapped.
*
* @param srcMem an image of a SetOperation where the image seed hash matches the default seed hash.
* See Memory
* @return a SetOperation backed by the given Memory
*/
public static SetOperation wrap(final Memory srcMem) {
return wrap(srcMem, ThetaUtil.DEFAULT_UPDATE_SEED);
}
/**
* Wrap takes the SetOperation image in Memory and refers to it directly.
* There is no data copying onto the java heap.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* wrapped.
*
* @param srcMem an image of a SetOperation where the hash of the given expectedSeed matches the image seed hash.
* See Memory
* @param expectedSeed the seed used to validate the given Memory image.
* See Update Hash Seed.
* @return a SetOperation backed by the given Memory
*/
public static SetOperation wrap(final Memory srcMem, final long expectedSeed) {
final byte famID = srcMem.getByte(FAMILY_BYTE);
final Family family = idToFamily(famID);
final int serVer = srcMem.getByte(SER_VER_BYTE);
if (serVer != 3) {
throw new SketchesArgumentException("SerVer must be 3: " + serVer);
}
switch (family) {
case UNION : {
return UnionImpl.wrapInstance(srcMem, expectedSeed);
}
case INTERSECTION : {
return IntersectionImpl.wrapInstance((WritableMemory)srcMem, expectedSeed, true);
}
default:
throw new SketchesArgumentException("SetOperation cannot wrap family: " + family.toString());
}
}
/**
* Wrap takes the SetOperation image in Memory and refers to it directly.
* There is no data copying onto the java heap.
* This method assumes the
* Default Update Seed.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* wrapped.
*
* @param srcMem an image of a SetOperation where the image seed hash matches the default seed hash.
* See Memory
* @return a SetOperation backed by the given Memory
*/
public static SetOperation wrap(final WritableMemory srcMem) {
return wrap(srcMem, ThetaUtil.DEFAULT_UPDATE_SEED);
}
/**
* Wrap takes the SetOperation image in Memory and refers to it directly.
* There is no data copying onto the java heap.
*
* Note: Only certain set operators during stateful operations can be serialized and thus
* wrapped.
*
* @param srcMem an image of a SetOperation where the hash of the given expectedSeed matches the image seed hash.
* See Memory
* @param expectedSeed the seed used to validate the given Memory image.
* See Update Hash Seed.
* @return a SetOperation backed by the given Memory
*/
public static SetOperation wrap(final WritableMemory srcMem, final long expectedSeed) {
final byte famID = srcMem.getByte(FAMILY_BYTE);
final Family family = idToFamily(famID);
final int serVer = srcMem.getByte(SER_VER_BYTE);
if (serVer != 3) {
throw new SketchesArgumentException("SerVer must be 3: " + serVer);
}
switch (family) {
case UNION : {
return UnionImpl.wrapInstance(srcMem, expectedSeed);
}
case INTERSECTION : {
return IntersectionImpl.wrapInstance(srcMem, expectedSeed, false);
}
default:
throw new SketchesArgumentException("SetOperation cannot wrap family: "
+ family.toString());
}
}
/**
* Returns the maximum required storage bytes given a nomEntries parameter for Union operations
* @param nomEntries Nominal Entries
* This will become the ceiling power of 2 if it is not.
* @return the maximum required storage bytes given a nomEntries parameter
*/
public static int getMaxUnionBytes(final int nomEntries) {
final int nomEnt = ceilingIntPowerOf2(nomEntries);
return (nomEnt << 4) + (Family.UNION.getMaxPreLongs() << 3);
}
/**
* Returns the maximum required storage bytes given a nomEntries parameter for Intersection
* operations
* @param nomEntries Nominal Entries
* This will become the ceiling power of 2 if it is not.
* @return the maximum required storage bytes given a nomEntries parameter
*/
public static int getMaxIntersectionBytes(final int nomEntries) {
final int nomEnt = ceilingIntPowerOf2(nomEntries);
final int bytes = (nomEnt << 4) + (Family.INTERSECTION.getMaxPreLongs() << 3);
return bytes;
}
/**
* Returns the maximum number of bytes for the returned CompactSketch, given the
* value of nomEntries of the first sketch A of AnotB.
* @param nomEntries this value must be a power of 2.
* @return the maximum number of bytes.
*/
public static int getMaxAnotBResultBytes(final int nomEntries) {
final int ceil = ceilingIntPowerOf2(nomEntries);
return 24 + (15 * ceil);
}
/**
* Gets the Family of this SetOperation
* @return the Family of this SetOperation
*/
public abstract Family getFamily();
/**
* Returns true if the backing resource of this is identical with the backing resource
* of that. The capacities must be the same. If this is a region,
* the region offset must also be the same.
*
* Note: Only certain set operators during stateful operations can be serialized.
* Only when they are stored into Memory will this be relevant.
*
* @param that A different non-null object
* @return true if the backing resource of this is the same as the backing resource
* of that.
*/
public abstract boolean isSameResource(Memory that);
//restricted
/**
* Gets the hash array in compact form.
* This is only useful during stateful operations.
* This should never be made public.
* @return the hash array
*/
abstract long[] getCache();
/**
* Gets the current count of retained entries.
* This is only useful during stateful operations.
* Intentionally not made public because behavior will be confusing to end user.
*
* @return Gets the current count of retained entries.
*/
abstract int getRetainedEntries();
/**
* Returns the seedHash established during class construction.
* @return the seedHash.
*/
abstract short getSeedHash();
/**
* Gets the current value of ThetaLong.
* Only useful during stateful operations.
* Intentionally not made public because behavior will be confusing to end user.
* @return the current value of ThetaLong.
*/
abstract long getThetaLong();
/**
* Returns true if this set operator is empty.
* Only useful during stateful operations.
* Intentionally not made public because behavior will be confusing to end user.
* @return true if this set operator is empty.
*/
abstract boolean isEmpty();
}
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