spring OpMinus 源码

spring OpMinus 代码

文件路径：/spring-expression/src/main/java/org/springframework/expression/spel/ast/OpMinus.java

/*
 * Copyright 2002-2022 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.expression.spel.ast;

import java.math.BigDecimal;
import java.math.BigInteger;

import org.springframework.asm.MethodVisitor;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.CodeFlow;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.util.Assert;
import org.springframework.util.NumberUtils;

/**
 * The minus operator supports:
 * <ul>
 * <li>subtraction of numbers
 * <li>subtraction of an int from a string of one character
 * (effectively decreasing that character), so 'd'-3='a'
 * </ul>
 *
 * <p>It can be used as a unary operator for numbers.
 * The standard promotions are performed when the operand types vary (double-int=double).
 * For other options it defers to the registered overloader.
 *
 * @author Andy Clement
 * @author Juergen Hoeller
 * @author Giovanni Dall'Oglio Risso
 * @author Sam Brannen
 * @since 3.0
 */
public class OpMinus extends Operator {

	public OpMinus(int startPos, int endPos, SpelNodeImpl... operands) {
		super("-", startPos, endPos, operands);
	}


	@Override
	public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
		SpelNodeImpl leftOp = getLeftOperand();

		if (this.children.length < 2) {  // if only one operand, then this is unary minus
			Object operand = leftOp.getValueInternal(state).getValue();
			if (operand instanceof Number number) {
				if (number instanceof BigDecimal bigDecimal) {
					return new TypedValue(bigDecimal.negate());
				}
				else if (number instanceof BigInteger bigInteger) {
					return new TypedValue(bigInteger.negate());
				}
				else if (number instanceof Double) {
					this.exitTypeDescriptor = "D";
					return new TypedValue(0 - number.doubleValue());
				}
				else if (number instanceof Float) {
					this.exitTypeDescriptor = "F";
					return new TypedValue(0 - number.floatValue());
				}
				else if (number instanceof Long) {
					this.exitTypeDescriptor = "J";
					return new TypedValue(0 - number.longValue());
				}
				else if (number instanceof Integer) {
					this.exitTypeDescriptor = "I";
					return new TypedValue(0 - number.intValue());
				}
				else if (number instanceof Short) {
					return new TypedValue(0 - number.shortValue());
				}
				else if (number instanceof Byte) {
					return new TypedValue(0 - number.byteValue());
				}
				else {
					// Unknown Number subtype -> best guess is double subtraction
					return new TypedValue(0 - number.doubleValue());
				}
			}
			return state.operate(Operation.SUBTRACT, operand, null);
		}

		Object left = leftOp.getValueInternal(state).getValue();
		Object right = getRightOperand().getValueInternal(state).getValue();

		if (left instanceof Number leftNumber && right instanceof Number rightNumber) {
			if (leftNumber instanceof BigDecimal || rightNumber instanceof BigDecimal) {
				BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
				BigDecimal rightBigDecimal = NumberUtils.convertNumberToTargetClass(rightNumber, BigDecimal.class);
				return new TypedValue(leftBigDecimal.subtract(rightBigDecimal));
			}
			else if (leftNumber instanceof Double || rightNumber instanceof Double) {
				this.exitTypeDescriptor = "D";
				return new TypedValue(leftNumber.doubleValue() - rightNumber.doubleValue());
			}
			else if (leftNumber instanceof Float || rightNumber instanceof Float) {
				this.exitTypeDescriptor = "F";
				return new TypedValue(leftNumber.floatValue() - rightNumber.floatValue());
			}
			else if (leftNumber instanceof BigInteger || rightNumber instanceof BigInteger) {
				BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
				BigInteger rightBigInteger = NumberUtils.convertNumberToTargetClass(rightNumber, BigInteger.class);
				return new TypedValue(leftBigInteger.subtract(rightBigInteger));
			}
			else if (leftNumber instanceof Long || rightNumber instanceof Long) {
				this.exitTypeDescriptor = "J";
				return new TypedValue(leftNumber.longValue() - rightNumber.longValue());
			}
			else if (CodeFlow.isIntegerForNumericOp(leftNumber) || CodeFlow.isIntegerForNumericOp(rightNumber)) {
				this.exitTypeDescriptor = "I";
				return new TypedValue(leftNumber.intValue() - rightNumber.intValue());
			}
			else {
				// Unknown Number subtypes -> best guess is double subtraction
				return new TypedValue(leftNumber.doubleValue() - rightNumber.doubleValue());
			}
		}

		if (left instanceof String theString && right instanceof Integer theInteger && theString.length() == 1) {
			// Implements character - int (ie. b - 1 = a)
			return new TypedValue(Character.toString((char) (theString.charAt(0) - theInteger)));
		}

		return state.operate(Operation.SUBTRACT, left, right);
	}

	@Override
	public String toStringAST() {
		if (this.children.length < 2) {  // unary minus
			return "-" + getLeftOperand().toStringAST();
		}
		return super.toStringAST();
	}

	@Override
	public SpelNodeImpl getRightOperand() {
		if (this.children.length < 2) {
			throw new IllegalStateException("No right operand");
		}
		return this.children[1];
	}

	@Override
	public boolean isCompilable() {
		if (!getLeftOperand().isCompilable()) {
			return false;
		}
		if (this.children.length > 1) {
			if (!getRightOperand().isCompilable()) {
				return false;
			}
		}
		return (this.exitTypeDescriptor != null);
	}

	@Override
	public void generateCode(MethodVisitor mv, CodeFlow cf) {
		getLeftOperand().generateCode(mv, cf);
		String leftDesc = getLeftOperand().exitTypeDescriptor;
		String exitDesc = this.exitTypeDescriptor;
		Assert.state(exitDesc != null, "No exit type descriptor");
		char targetDesc = exitDesc.charAt(0);
		CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, leftDesc, targetDesc);
		if (this.children.length > 1) {
			cf.enterCompilationScope();
			getRightOperand().generateCode(mv, cf);
			String rightDesc = getRightOperand().exitTypeDescriptor;
			cf.exitCompilationScope();
			CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, rightDesc, targetDesc);
			switch (targetDesc) {
				case 'I' -> mv.visitInsn(ISUB);
				case 'J' -> mv.visitInsn(LSUB);
				case 'F' -> mv.visitInsn(FSUB);
				case 'D' -> mv.visitInsn(DSUB);
				default -> throw new IllegalStateException(
						"Unrecognized exit type descriptor: '" + this.exitTypeDescriptor + "'");
			}
		}
		else {
			switch (targetDesc) {
				case 'I' -> mv.visitInsn(INEG);
				case 'J' -> mv.visitInsn(LNEG);
				case 'F' -> mv.visitInsn(FNEG);
				case 'D' -> mv.visitInsn(DNEG);
				default -> throw new IllegalStateException(
						"Unrecognized exit type descriptor: '" + this.exitTypeDescriptor + "'");
			}
		}
		cf.pushDescriptor(this.exitTypeDescriptor);
	}

}

相关信息

spring 源码目录

相关文章

spring Assign 源码

spring AstUtils 源码

spring BeanReference 源码

spring BooleanLiteral 源码

spring CompoundExpression 源码

spring ConstructorReference 源码

spring Elvis 源码

spring FloatLiteral 源码

spring FormatHelper 源码

spring FunctionReference 源码