spring OpPlus 源码

spring OpPlus 代码

文件路径：/spring-expression/src/main/java/org/springframework/expression/spel/ast/OpPlus.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.core.convert.TypeDescriptor;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypeConverter;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.CodeFlow;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.NumberUtils;

/**
 * The plus operator will:
 * <ul>
 * <li>add numbers
 * <li>concatenate strings
 * </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 Ivo Smid
 * @author Giovanni Dall'Oglio Risso
 * @since 3.0
 */
public class OpPlus extends Operator {

	public OpPlus(int startPos, int endPos, SpelNodeImpl... operands) {
		super("+", startPos, endPos, operands);
		Assert.notEmpty(operands, "Operands must not be empty");
	}


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

		if (this.children.length < 2) {  // if only one operand, then this is unary plus
			Object operandOne = leftOp.getValueInternal(state).getValue();
			if (operandOne instanceof Number) {
				if (operandOne instanceof Double) {
					this.exitTypeDescriptor = "D";
				}
				else if (operandOne instanceof Float) {
					this.exitTypeDescriptor = "F";
				}
				else if (operandOne instanceof Long) {
					this.exitTypeDescriptor = "J";
				}
				else if (operandOne instanceof Integer) {
					this.exitTypeDescriptor = "I";
				}
				return new TypedValue(operandOne);
			}
			return state.operate(Operation.ADD, operandOne, null);
		}

		TypedValue operandOneValue = leftOp.getValueInternal(state);
		Object leftOperand = operandOneValue.getValue();
		TypedValue operandTwoValue = getRightOperand().getValueInternal(state);
		Object rightOperand = operandTwoValue.getValue();

		if (leftOperand instanceof Number leftNumber && rightOperand 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.add(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.add(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 addition
				return new TypedValue(leftNumber.doubleValue() + rightNumber.doubleValue());
			}
		}

		if (leftOperand instanceof String leftString && rightOperand instanceof String rightString) {
			this.exitTypeDescriptor = "Ljava/lang/String";
			return new TypedValue(leftString + rightString);
		}

		if (leftOperand instanceof String) {
			return new TypedValue(
					leftOperand + (rightOperand == null ? "null" : convertTypedValueToString(operandTwoValue, state)));
		}

		if (rightOperand instanceof String) {
			return new TypedValue(
					(leftOperand == null ? "null" : convertTypedValueToString(operandOneValue, state)) + rightOperand);
		}

		return state.operate(Operation.ADD, leftOperand, rightOperand);
	}

	@Override
	public String toStringAST() {
		if (this.children.length < 2) {  // unary plus
			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];
	}

	/**
	 * Convert operand value to string using registered converter or using
	 * {@code toString} method.
	 * @param value typed value to be converted
	 * @param state expression state
	 * @return {@code TypedValue} instance converted to {@code String}
	 */
	private static String convertTypedValueToString(TypedValue value, ExpressionState state) {
		TypeConverter typeConverter = state.getEvaluationContext().getTypeConverter();
		TypeDescriptor typeDescriptor = TypeDescriptor.valueOf(String.class);
		if (typeConverter.canConvert(value.getTypeDescriptor(), typeDescriptor)) {
			return String.valueOf(typeConverter.convertValue(value.getValue(),
					value.getTypeDescriptor(), typeDescriptor));
		}
		return String.valueOf(value.getValue());
	}

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

	/**
	 * Walk through a possible tree of nodes that combine strings and append
	 * them all to the same (on stack) StringBuilder.
	 */
	private void walk(MethodVisitor mv, CodeFlow cf, @Nullable SpelNodeImpl operand) {
		if (operand instanceof OpPlus plus) {
			walk(mv, cf, plus.getLeftOperand());
			walk(mv, cf, plus.getRightOperand());
		}
		else if (operand != null) {
			cf.enterCompilationScope();
			operand.generateCode(mv,cf);
			if (!"Ljava/lang/String".equals(cf.lastDescriptor())) {
				mv.visitTypeInsn(CHECKCAST, "java/lang/String");
			}
			cf.exitCompilationScope();
			mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
		}
	}

	@Override
	public void generateCode(MethodVisitor mv, CodeFlow cf) {
		if ("Ljava/lang/String".equals(this.exitTypeDescriptor)) {
			mv.visitTypeInsn(NEW, "java/lang/StringBuilder");
			mv.visitInsn(DUP);
			mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "()V", false);
			walk(mv, cf, getLeftOperand());
			walk(mv, cf, getRightOperand());
			mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;", false);
		}
		else {
			this.children[0].generateCode(mv, cf);
			String leftDesc = this.children[0].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();
				this.children[1].generateCode(mv, cf);
				String rightDesc = this.children[1].exitTypeDescriptor;
				cf.exitCompilationScope();
				CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, rightDesc, targetDesc);
				switch (targetDesc) {
					case 'I' -> mv.visitInsn(IADD);
					case 'J' -> mv.visitInsn(LADD);
					case 'F' -> mv.visitInsn(FADD);
					case 'D' -> mv.visitInsn(DADD);
					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