org.springframework.expression.spel.ast

Class Elvis

java.lang.Object

org.springframework.expression.spel.ast.SpelNodeImpl

org.springframework.expression.spel.ast.Elvis

All Implemented Interfaces:

Opcodes, SpelNode

public class Elvis
extends SpelNodeImpl

Represents the elvis operator ?:. For an expression "a?:b" if a is not null, the value of the expression is "a", if a is null then the value of the expression is "b".

Since:

3.0

Author:

Andy Clement, Juergen Hoeller

Field Summary

Fields inherited from class org.springframework.expression.spel.ast.SpelNodeImpl

children, exitTypeDescriptor, pos

Fields inherited from interface org.springframework.asm.Opcodes

AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_DEPRECATED, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_MANDATED, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASM4, ASM5, 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, 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, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, TOP, UNINITIALIZED_THIS, V1_1, V1_2, V1_3, V1_4, V1_5, V1_6, V1_7, V1_8

Constructor Summary

Constructors

Constructor and Description
Elvis(int pos, SpelNodeImpl... args)

Method Summary

Modifier and Type	Method and Description
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 not null, return it.
boolean	isCompilable() Check whether a node can be compiled to bytecode.
String	toStringAST()

Methods inherited from class org.springframework.expression.spel.ast.SpelNodeImpl

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

Methods inherited from class java.lang.Object

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

Constructor Detail

Elvis

public Elvis(int pos,
             SpelNodeImpl... args)

Method Detail

getValueInternal

public TypedValue getValueInternal(ExpressionState state)
                            throws EvaluationException

Evaluate the condition and if not null, return it. If it is null, return the other value.

Specified by:

getValueInternal in class SpelNodeImpl

Parameters:

state - the expression state

Throws:

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

toStringAST

public String toStringAST()

Returns:

the string form of this AST node

isCompilable

public boolean isCompilable()

Description copied from class: 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.

Overrides:

isCompilable in class SpelNodeImpl

Returns:

true if this node can be compiled to bytecode

generateCode

public void generateCode(MethodVisitor mv,
                         CodeFlow cf)

Description copied from class: 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. For example it will include information about the type of the object currently on the stack.

Overrides:

generateCode in class SpelNodeImpl

Parameters:

mv - the ASM MethodVisitor into which code should be generated

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