程序包 cn.taketoday.expression.spel.ast

类 Elvis

java.lang.Object

cn.taketoday.expression.spel.ast.SpelNodeImpl

cn.taketoday.expression.spel.ast.Elvis

所有已实现的接口:

Opcodes, SpelNode

public class Elvis
extends SpelNodeImpl

Represents the Elvis operator ?:. For an expression a?:b if a is neither null nor an empty String, the value of the expression is a. If a is null or the empty String, then the value of the expression is b.

从以下版本开始:

4.0

作者:

Andy Clement, Juergen Hoeller

字段概要

从类继承的字段 cn.taketoday.expression.spel.ast.SpelNodeImpl

children, exitTypeDescriptor

从接口继承的字段 cn.taketoday.bytecode.Opcodes

AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_DEPRECATED, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_MANDATED, ACC_MODULE, ACC_NATIVE, ACC_OPEN, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_RECORD, ACC_STATIC, ACC_STATIC_PHASE, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_TRANSITIVE, ACC_VARARGS, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DMUL, DNEG, DOUBLE, DREM, DRETURN, DSTORE, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F_APPEND, F_CHOP, F_FULL, F_NEW, F_SAME, F_SAME1, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAT, FMUL, FNEG, FREM, FRETURN, FSTORE, FSUB, GETFIELD, GETSTATIC, GOTO, H_GETFIELD, H_GETSTATIC, H_INVOKEINTERFACE, H_INVOKESPECIAL, H_INVOKESTATIC, H_INVOKEVIRTUAL, H_NEWINVOKESPECIAL, H_PUTFIELD, H_PUTSTATIC, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, IMUL, INEG, INSTANCEOF, INTEGER, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISUB, IUSHR, IXOR, JAVA_VERSION, JSR, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDIV, LLOAD, LMUL, LNEG, LONG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, NULL, POP, POP2, PRIVATE_FINAL_STATIC, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SOURCE_DEPRECATED, SOURCE_MASK, SWAP, SWITCH_STYLE_HASH, SWITCH_STYLE_HASHONLY, SWITCH_STYLE_TRIE, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, TOP, UNINITIALIZED_THIS, V_PREVIEW, V1_1, V1_2, V1_3, V1_4, V1_5, V1_6, V1_7, V1_8, V10, V11, V12, V13, V14, V15, V16, V17, V18, V19, V20, V21, V9

构造器概要

构造器

构造器	说明
Elvis(int startPos, int endPos, SpelNodeImpl... args)

方法概要

修饰符和类型	方法	说明
private void	computeExitTypeDescriptor()
void	generateCode(MethodVisitor mv, CodeFlow cf)	Generate the bytecode for this node into the supplied visitor.
TypedValue	getValueInternal(ExpressionState state)	Evaluate the condition and if neither null nor an empty String, return it.
boolean	isCompilable()	Check whether a node can be compiled to bytecode.
String	toStringAST()	Return the string form the this AST node.

从类继承的方法 cn.taketoday.expression.spel.ast.SpelNodeImpl

generateCodeForArgument, generateCodeForArguments, getChild, getChildCount, getEndPosition, getExitDescriptor, getObjectClass, getStartPosition, getTypedValue, getValue, getValue, getValueRef, isWritable, nextChildIs, setValue, setValueInternal

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

Elvis

public Elvis(int startPos,
 int endPos,
 SpelNodeImpl... args)

方法详细资料

getValueInternal

public TypedValue getValueInternal(ExpressionState state)
                            throws EvaluationException

Evaluate the condition and if neither null nor an empty String, return it. If it is null or an empty String, return the other value.

指定者:

getValueInternal 在类中 SpelNodeImpl

参数:

state - the expression state

抛出:

EvaluationException - if the condition does not evaluate correctly to a boolean or there is a problem executing the chosen alternative

toStringAST

public String toStringAST()

从接口复制的说明: SpelNode

Return the string form the this AST node.

返回:

the string form

isCompilable

public boolean isCompilable()

从类复制的说明: SpelNodeImpl

Check whether a node can be compiled to bytecode. The reasoning in each node may be different but will typically involve checking whether the exit type descriptor of the node is known and any relevant child nodes are compilable.

覆盖:

isCompilable 在类中 SpelNodeImpl

返回:

true if this node can be compiled to bytecode

generateCode

public void generateCode(MethodVisitor mv,
 CodeFlow cf)

从类复制的说明: SpelNodeImpl

Generate the bytecode for this node into the supplied visitor. Context info about the current expression being compiled is available in the codeflow object, e.g. including information about the type of the object currently on the stack.

覆盖:

generateCode 在类中 SpelNodeImpl

参数:

mv - the ASM MethodVisitor into which code should be generated

cf - a context object with info about what is on the stack

computeExitTypeDescriptor

private void computeExitTypeDescriptor()