/*
* Copyright 2016 Nabarun Mondal
* 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 com.noga.njexl.lang;
import java.math.MathContext;
/**
* A derived arithmetic that allows different threads to operate with
* different strict/lenient/math modes using the same JexlEngine.
* @since 2.1
*/
public class JexlThreadedArithmetic extends JexlArithmetic {
/** Holds the threaded version of some arithmetic features. */
static class Features {
/** Default ctor. */
Features() {}
/** Whether this JexlArithmetic instance behaves in strict or lenient mode. */
private Boolean lenient = null;
/** The big decimal math context. */
private MathContext mathContext = null;
/** The big decimal scale. */
private Integer mathScale = null;
}
/**
* Standard ctor.
* @param lenient lenient versus strict evaluation flag
*/
public JexlThreadedArithmetic(boolean lenient) {
super(lenient);
}
/**
* Creates a JexlThreadedArithmetic instance.
* @param lenient whether this arithmetic is lenient or strict
* @param bigdContext the math context instance to use for +,-,/,*,% operations on big decimals.
* @param bigdScale the scale used for big decimals.
*/
public JexlThreadedArithmetic(boolean lenient, MathContext bigdContext, int bigdScale) {
super(lenient, bigdContext, bigdScale);
}
/** Whether this JexlArithmetic instance behaves in strict or lenient mode for this thread. */
static final ThreadLocal<Features> FEATURES = new ThreadLocal<Features>() {
@Override
protected synchronized Features initialValue() {
return new Features();
}
};
/**
* Overrides the default behavior and sets whether this JexlArithmetic instance triggers errors
* during evaluation when null is used as an operand for the current thread.
* <p>It is advised to protect calls by either calling JexlThreadedArithmetic.setLenient explicitly
* before evaluation or add a try/finally clause resetting the flag to avoid unexpected reuse of the lenient
* flag value through thread pools side-effects.</p>
* @see JexlEngine#setSilent
* @see JexlEngine#setDebug
* @param flag true means no JexlException will occur, false allows them, null reverts to default behavior
*/
public static void setLenient(Boolean flag) {
FEATURES.get().lenient = flag;
}
/**
* Sets the math scale.
* <p>The goal and constraints are the same than for setLenient.</p>
* @param scale the scale
*/
public static void setMathScale(Integer scale) {
FEATURES.get().mathScale = scale;
}
/**
* Sets the math context.
* <p>The goal and constraints are the same than for setLenient.</p>
* @param mc the math context
*/
public static void setMathContext(MathContext mc) {
FEATURES.get().mathContext = mc;
}
/** {@inheritDoc} */
@Override
public boolean isLenient() {
Boolean lenient = FEATURES.get().lenient;
return lenient == null ? super.isLenient() : lenient.booleanValue();
}
@Override
public int getMathScale() {
Integer scale = FEATURES.get().mathScale;
return scale == null ? super.getMathScale() : scale.intValue();
}
@Override
public MathContext getMathContext() {
MathContext mc = FEATURES.get().mathContext;
return mc == null? super.getMathContext() : mc;
}
}