com.tangosol.util.filter.ExtractorFilter Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of coherence Show documentation
Show all versions of coherence Show documentation
Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2021, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.util.filter;
import com.tangosol.internal.util.invoke.Lambdas;
import com.tangosol.io.ExternalizableLite;
import com.tangosol.io.pof.PofReader;
import com.tangosol.io.pof.PofWriter;
import com.tangosol.io.pof.PortableObject;
import com.tangosol.util.Filter;
import com.tangosol.util.InvocableMapHelper;
import com.tangosol.util.MapIndex;
import com.tangosol.util.QueryMap;
import com.tangosol.util.ValueExtractor;
import com.tangosol.util.extractor.ChainedExtractor;
import com.tangosol.util.extractor.ReflectionExtractor;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.json.bind.annotation.JsonbProperty;
/**
* Base Filter implementation for doing extractor-based processing.
*
* @param the type of the input argument to the filter
* @param the type of the attribute extracted from the input argument
*
* @author cp/gg 2002.11.01
*/
public abstract class ExtractorFilter
extends AbstractQueryRecorderFilter
implements EntryFilter, ExternalizableLite, PortableObject, IndexAwareFilter
{
// ----- constructors ---------------------------------------------------
/**
* Default constructor (necessary for the ExternalizableLite interface).
*/
public ExtractorFilter()
{
}
/**
* Construct a ExtractorFilter for a given ValueExtractor.
*
* @param extractor the ValueExtractor to use by this filter
*/
public ExtractorFilter(ValueExtractor extractor)
{
azzert(extractor != null);
m_extractor = Lambdas.ensureRemotable(extractor);
}
/**
* Construct an ExtractorFilter for a given method name.
*
* @param sMethod a method name to make a {@link ReflectionExtractor}
* for; this parameter can also be a dot-delimited
* sequence of method names which would result in an
* ExtractorFilter based on the {@link ChainedExtractor}
* that is based on an array of corresponding
* ReflectionExtractor objects
*/
public ExtractorFilter(String sMethod)
{
m_extractor = sMethod.indexOf('.') < 0
? new ReflectionExtractor(sMethod)
: new ChainedExtractor(sMethod);
}
// ----- Filter interface -----------------------------------------------
/**
* {@inheritDoc}
*/
public boolean evaluate(T target)
{
return evaluateExtracted(extract(target));
}
// ----- EntryFilter interface ------------------------------------------
/**
* {@inheritDoc}
*/
public boolean evaluateEntry(Map.Entry entry)
{
ValueExtractor extractor = getValueExtractor();
return evaluateExtracted(entry instanceof QueryMap.Entry
? ((QueryMap.Entry) entry).extract(extractor)
: InvocableMapHelper.extractFromEntry(extractor, entry));
}
// ----- inheritance support and accessors ------------------------------
/**
* Evaluate the specified extracted value.
*
* @param extracted an extracted value to evaluate
*
* @return true iff the test passes
*/
protected abstract boolean evaluateExtracted(E extracted);
/**
* Get the result of ValueExtractor invocation.
*
* @param o the object on which to invoke the ValueExtractor;
* must not be null
*
* @return the result of the method invocation
*
* @throws com.tangosol.util.WrapperException if this ValueExtractor
* encounters an exception in the course of extracting the value
*/
protected E extract(T o)
{
return getValueExtractor().extract(o);
}
/**
* Obtain the ValueExtractor used by this filter.
*
* @return the ValueExtractor used by this filter
*/
public ValueExtractor getValueExtractor()
{
return m_extractor;
}
// ----- IndexAwareFilter interface -------------------------------------
/**
* {@inheritDoc}
*/
public int calculateEffectiveness(Map mapIndexes, Set setKeys)
{
MapIndex index = (MapIndex) mapIndexes.get(getValueExtractor());
return index == null ? calculateIteratorEffectiveness(setKeys.size())
: index.getIndexContents().size();
}
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
public Filter applyIndex(Map mapIndexes, Set setKeys)
{
MapIndex index = (MapIndex) mapIndexes.get(getValueExtractor());
if (index == null)
{
return this;
}
Set setMatch = new HashSet();
Map> mapValues = index.getIndexContents();
for (Map.Entry> entry : mapValues.entrySet())
{
if (evaluateExtracted(entry.getKey()))
{
setMatch.addAll(ensureSafeSet(entry.getValue()));
}
}
setKeys.retainAll(setMatch);
return null;
}
// ----- helpers --------------------------------------------------------
/**
* Helper method to calculate effectiveness (or rather ineffectiveness) of
* a simple iteration against a key set that has to be performed due to an
* absence of corresponding index.
*
* @param cKeys the number of keys to iterate through
*
* @return an effectiveness estimate
*/
public static int calculateIteratorEffectiveness(int cKeys)
{
// convert int to long to prevent integer overflow
long lCost = ((long) EVAL_COST) * cKeys;
return lCost <= Integer.MAX_VALUE ? (int) lCost : Integer.MAX_VALUE;
}
// ----- ExternalizableLite interface -----------------------------------
@Override
public void readExternal(DataInput in)
throws IOException
{
m_extractor = readObject(in);
}
@Override
public void writeExternal(DataOutput out)
throws IOException
{
writeObject(out, m_extractor);
}
// ----- PortableObject interface ---------------------------------------
@Override
public void readExternal(PofReader in)
throws IOException
{
m_extractor = in.readObject(0);
}
@Override
public void writeExternal(PofWriter out)
throws IOException
{
out.writeObject(0, m_extractor);
}
// ------ helper method -------------------------------------------------
/**
* Return a non-null Set.
*
* @param set the set to ensure
*
* @return the safe set
*/
protected static Set ensureSafeSet(Set set)
{
return set == null ? Collections.emptySet() : set;
}
// ----- constants ------------------------------------------------------
/**
* The evaluation cost as a factor to the single index access operation.
*
* @see IndexAwareFilter#calculateEffectiveness(Map, Set)
*/
public static int EVAL_COST = 1000;
// ----- data members ---------------------------------------------------
/**
* The ValueExtractor used by this filter.
*/
@JsonbProperty("extractor")
protected ValueExtractor m_extractor;
}