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Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2020, 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.extractor;
import com.tangosol.util.ValueExtractor;
import com.tangosol.util.comparator.SafeComparator;
import com.tangosol.io.pof.PofReader;
import com.tangosol.io.pof.PofWriter;
import java.util.Comparator;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
import javax.json.bind.annotation.JsonbProperty;
/**
* A synthetic ValueExtractor that returns a result of comparison between two
* values extracted from the same target. In a most general case, the extracted
* value represents an Integer value calculated accordingly to the contract of
* {@link Comparable#compareTo} or {@link Comparator#compare} methods. However,
* in more specific cases, when the compared values are of common numeric type,
* the ComparisonValueExtractor will return a numeric difference between those
* values. The Java type of the comparing values will dictate the Java type of
* the result.
*
* For example, lets assume that a cache contains business objects that have two
* properties: SellPrice and BuyPrice (both double). Then, to query for all
* objects that have SellPrice less than BuyPrice we would use the following:
*
* ValueExtractor extractDiff = new ComparisonValueExtractor(
* new ReflectionExtractor("getSellPrice"),
* new ReflectionExtractor("getBuyPrice"));
* Filter filter = new LessFilter(extractDiff, new Double(0.0));
* Set entries = cache.entrySet(filter);
*
*
* @author gg 2008.02.15
* @since Coherence 3.4
*/
public class ComparisonValueExtractor
extends AbstractCompositeExtractor
{
/**
* Default constructor (necessary for the ExternalizableLite interface).
*/
public ComparisonValueExtractor()
{
}
/**
* Construct a ComparisonValueExtractor based on two method names.
* Note: values returned by both methods must be {@link Comparable}.
*
* @param sMethod1 the name of the first method to invoke via reflection
* @param sMethod2 the name of the second method to invoke via reflection
*/
public ComparisonValueExtractor(String sMethod1, String sMethod2)
{
this(sMethod1, sMethod2, null);
}
/**
* Construct a ComparisonValueExtractor based on two method names and a
* Comparator object.
*
* @param sMethod1 the name of the first method to invoke via reflection
* @param sMethod2 the name of the second method to invoke via reflection
* @param comp the comparator used to compare the extracted values (optional)
*/
public ComparisonValueExtractor(String sMethod1, String sMethod2,
Comparator comp)
{
this(new ReflectionExtractor(sMethod1),
new ReflectionExtractor(sMethod2), comp);
}
/**
* Construct a ComparisonValueExtractor based on two specified extractors.
* Note: values returned by both extractors must be {@link Comparable}.
*
* @param ve1 the ValueExtractor for the first value
* @param ve2 the ValueExtractor for the second value
*/
public ComparisonValueExtractor(ValueExtractor ve1, ValueExtractor ve2)
{
this(ve1, ve2, null);
}
/**
* Construct a ComparisonValueExtractor based on two specified extractors and
* a Comparator object.
*
* @param ve1 the ValueExtractor for the first value
* @param ve2 the ValueExtractor for the second value
* @param comp the comparator used to compare the extracted values (optional)
*/
public ComparisonValueExtractor(ValueExtractor ve1, ValueExtractor ve2,
Comparator comp)
{
super(new ValueExtractor[] {ve1, ve2});
m_comparator = comp;
}
// ----- accessors ------------------------------------------------------
/**
* Return a Comparator used by this extractor.
*
* @return a Comparator used by this extractor; null if the natural value
* comparison should be used
*/
public Comparator getComparator()
{
return m_comparator;
}
// ----- ValueExtractor interface ---------------------------------------
/**
* {@inheritDoc}
*/
public E extract(Object oTarget)
{
ValueExtractor[] aExtractor = getExtractors();
Comparator comparator = getComparator();
Object o1 = aExtractor[0].extract(oTarget);
Object o2 = aExtractor[1].extract(oTarget);
if (o1 instanceof Number && o2 instanceof Number && comparator == null)
{
Number num1 = (Number) o1;
Number num2 = (Number) o2;
int nType;
if (num1.getClass() == num2.getClass())
{
// most common case; same types
nType = getStreamFormat(o1);
}
else
{
int[] anType = new int[] {
FMT_BYTE, // 0
FMT_SHORT, // 1
FMT_INT, // 2
FMT_LONG, // 3
FMT_FLOAT, // 4
FMT_DOUBLE, // 5
FMT_INTEGER, // 6
FMT_DECIMAL // 7
};
int nType1 = getStreamFormat(num1);
int nType2 = getStreamFormat(num2);
int cTypes, ix1, ix2;
ix1 = ix2 = cTypes = anType.length;
for (int i = 0; i < cTypes; i++)
{
int nT = anType[i];
if (nT == nType1)
{
ix1 = i;
}
if (nT == nType2)
{
ix2 = i;
}
}
switch (Math.max(ix1, ix2))
{
case 1: case 2:
nType = FMT_INT;
break;
case 3:
nType = FMT_LONG;
break;
case 4: case 5:
nType = FMT_DOUBLE;
break;
case 6: case 7:
nType = FMT_INTEGER;
num1 = ensureBigDecimal(num1);
num2 = ensureBigDecimal(num2);
break;
default:
nType = FMT_NONE;
break;
}
}
switch (nType)
{
case FMT_BYTE:
case FMT_SHORT:
case FMT_INT:
return (E) Integer.valueOf(num1.intValue() - num2.intValue());
case FMT_LONG:
return (E) Long.valueOf(num1.longValue() - num2.longValue());
case FMT_FLOAT:
return (E) new Float(num1.floatValue() - num2.floatValue());
case FMT_DOUBLE:
return (E) new Double(num1.doubleValue() - num2.doubleValue());
case FMT_INTEGER:
return (E) ((BigInteger) num1).subtract((BigInteger) num2);
case FMT_DECIMAL:
return (E) ((BigDecimal) num1).subtract((BigDecimal) num2);
}
}
return (E) Integer.valueOf(
SafeComparator.compareSafe(comparator, o1, o2));
}
// ----- ExternalizableLite interface -----------------------------------
/**
* {@inheritDoc}
*/
public void readExternal(DataInput in)
throws IOException
{
super.readExternal(in);
m_comparator = readObject(in);
}
/**
* {@inheritDoc}
*/
public void writeExternal(DataOutput out)
throws IOException
{
super.writeExternal(out);
writeObject(out, m_comparator);
}
// ----- PortableObject interface ---------------------------------------
/**
* {@inheritDoc}
*/
public void readExternal(PofReader in)
throws IOException
{
super.readExternal(in);
m_comparator = in.readObject(1);
}
/**
* {@inheritDoc}
*/
public void writeExternal(PofWriter out)
throws IOException
{
super.writeExternal(out);
out.writeObject(1, m_comparator);
}
// ----- data members ---------------------------------------------------
/**
* An underlying Comparator object (optional).
*/
@JsonbProperty("comparator")
protected Comparator m_comparator;
}