freemarker.template.utility.OptimizerUtil Maven / Gradle / Ivy
/*
* 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 freemarker.template.utility;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
*/
public class OptimizerUtil {
private static final BigInteger INTEGER_MIN = new BigInteger(Integer.toString(Integer.MIN_VALUE));
private static final BigInteger INTEGER_MAX = new BigInteger(Integer.toString(Integer.MAX_VALUE));
private static final BigInteger LONG_MIN = new BigInteger(Long.toString(Long.MIN_VALUE));
private static final BigInteger LONG_MAX = new BigInteger(Long.toString(Long.MAX_VALUE));
private OptimizerUtil() {
}
public static List optimizeListStorage(List list) {
switch(list.size())
{
case 0:
{
return Collections.EMPTY_LIST;
}
case 1:
{
return Collections.singletonList(list.get(0));
}
default:
{
if (list instanceof ArrayList) {
((ArrayList) list).trimToSize();
}
return list;
}
}
}
/**
* This is needed to reverse the extreme conversions in arithmetic
* operations so that numbers can be meaningfully used with models that
* don't know what to do with a BigDecimal. Of course, this will make
* impossible for these models (i.e. Jython) to receive a BigDecimal even if
* it was originally placed as such in the data model. However, since
* arithmetic operations aggressively erase the information regarding the
* original number type, we have no other choice to ensure expected operation
* in majority of cases.
*/
public static Number optimizeNumberRepresentation(Number number) {
if (number instanceof BigDecimal) {
BigDecimal bd = (BigDecimal) number;
if (bd.scale() == 0) {
// BigDecimal -> BigInteger
number = bd.unscaledValue();
} else {
double d = bd.doubleValue();
if (d != Double.POSITIVE_INFINITY && d != Double.NEGATIVE_INFINITY) {
// BigDecimal -> Double
return Double.valueOf(d);
}
}
}
if (number instanceof BigInteger) {
BigInteger bi = (BigInteger) number;
if (bi.compareTo(INTEGER_MAX) <= 0 && bi.compareTo(INTEGER_MIN) >= 0) {
// BigInteger -> Integer
return Integer.valueOf(bi.intValue());
}
if (bi.compareTo(LONG_MAX) <= 0 && bi.compareTo(LONG_MIN) >= 0) {
// BigInteger -> Long
return Long.valueOf(bi.longValue());
}
}
return number;
}
}