SpelNodeImpl (Spring Framework 5.2.16.RELEASE API)

java.lang.Object
- org.springframework.expression.spel.ast.SpelNodeImpl

All Implemented Interfaces:

Opcodes, SpelNode

Direct Known Subclasses:

Assign, BeanReference, CompoundExpression, ConstructorReference, Elvis, FunctionReference, Identifier, Indexer, InlineList, InlineMap, Literal, MethodReference, Operator, OperatorNot, Projection, PropertyOrFieldReference, QualifiedIdentifier, Selection, Ternary, TypeReference, VariableReference
```
public abstract class SpelNodeImpl
extends Object
implements SpelNode, Opcodes
```
The common supertype of all AST nodes in a parsed Spring Expression Language format expression.

Since:

3.0

Author:

Andy Clement, Juergen Hoeller

Field Summary

Fields
Modifier and Type Field and Description

protected SpelNodeImpl[] children

protected String exitTypeDescriptor
Indicates the type descriptor for the result of this expression node.
- 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_MODULE, ACC_NATIVE, ACC_OPEN, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, 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, ASM4, ASM5, ASM6, ASM7, ASM8_EXPERIMENTAL, 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, SOURCE_DEPRECATED, SOURCE_MASK, SWAP, 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, V9

Fields
Modifier and Type	Field and Description
`protected SpelNodeImpl[]`	`children`
`protected String`	`exitTypeDescriptor` Indicates the type descriptor for the result of this expression node.

Constructor Summary

Constructors
Constructor and Description

SpelNodeImpl(int startPos, int endPos, SpelNodeImpl... operands)

Constructors
Constructor and Description
`SpelNodeImpl(int startPos, int endPos, SpelNodeImpl... operands)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`generateCode(MethodVisitor mv, CodeFlow cf)` Generate the bytecode for this node into the supplied visitor.
`protected static void`	`generateCodeForArgument(MethodVisitor mv, CodeFlow cf, SpelNodeImpl argument, String paramDesc)` Ask an argument to generate its bytecode and then follow it up with any boxing/unboxing/checkcasting to ensure it matches the expected parameter descriptor.
`protected static void`	`generateCodeForArguments(MethodVisitor mv, CodeFlow cf, Member member, SpelNodeImpl[] arguments)` Generate code that handles building the argument values for the specified method.
`SpelNode`	`getChild(int index)` Helper method that returns a SpelNode rather than an Antlr Tree node.
`int`	`getChildCount()` Return the number of children under this node.
`int`	`getEndPosition()` Return the end position of this AST node in the expression string.
`String`	`getExitDescriptor()`
`Class<?>`	`getObjectClass(Object obj)` Determine the class of the object passed in, unless it is already a class object.
`int`	`getStartPosition()` Return the start position of this AST node in the expression string.
`TypedValue`	`getTypedValue(ExpressionState expressionState)` Evaluate the expression node in the context of the supplied expression state and return the typed value.
`Object`	`getValue(ExpressionState expressionState)` Evaluate the expression node in the context of the supplied expression state and return the value.
`protected <T> T`	`getValue(ExpressionState state, Class<T> desiredReturnType)`
`abstract TypedValue`	`getValueInternal(ExpressionState expressionState)`
`protected ValueRef`	`getValueRef(ExpressionState state)`
`boolean`	`isCompilable()` Check whether a node can be compiled to bytecode.
`boolean`	`isWritable(ExpressionState expressionState)` Determine if this expression node will support a setValue() call.
`protected boolean`	`nextChildIs(Class<?>... classes)` Return `true` if the next child is one of the specified classes.
`void`	`setValue(ExpressionState expressionState, Object newValue)` Evaluate the expression to a node and then set the new value on that node.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.springframework.expression.spel.SpelNode
toStringAST

- Field Detail
  - children
```
protected SpelNodeImpl[] children
```
  - exitTypeDescriptor
```
@Nullable
protected volatile String exitTypeDescriptor
```
    Indicates the type descriptor for the result of this expression node. This is set as soon as it is known. For a literal node it is known immediately. For a property access or method invocation it is known after one evaluation of that node.
    The descriptor is like the bytecode form but is slightly easier to work with. It does not include the trailing semicolon (for non array reference types). Some examples: Ljava/lang/String, I, [I
- Constructor Detail
  - SpelNodeImpl
```
public SpelNodeImpl(int startPos,
                    int endPos,
                    SpelNodeImpl... operands)
```
- Method Detail
  - nextChildIs
```
protected boolean nextChildIs(Class<?>... classes)
```
    Return true if the next child is one of the specified classes.
  - getValue
```
@Nullable
public final Object getValue(ExpressionState expressionState)
                                throws EvaluationException
```
    Description copied from interface: SpelNode
    
    Evaluate the expression node in the context of the supplied expression state and return the value.
    
    Specified by:
    
    getValue in interface SpelNode
    
    Parameters:
    
    expressionState - the current expression state (includes the context)
    
    Returns:
    
    the value of this node evaluated against the specified state
    
    Throws:
    
    EvaluationException
  - getTypedValue
```
public final TypedValue getTypedValue(ExpressionState expressionState)
                               throws EvaluationException
```
    Description copied from interface: SpelNode
    
    Evaluate the expression node in the context of the supplied expression state and return the typed value.
    
    Specified by:
    
    getTypedValue in interface SpelNode
    
    Parameters:
    
    expressionState - the current expression state (includes the context)
    
    Returns:
    
    the type value of this node evaluated against the specified state
    
    Throws:
    
    EvaluationException
  - isWritable
```
public boolean isWritable(ExpressionState expressionState)
                   throws EvaluationException
```
    Description copied from interface: SpelNode
    
    Determine if this expression node will support a setValue() call.
    
    Specified by:
    
    isWritable in interface SpelNode
    
    Parameters:
    
    expressionState - the current expression state (includes the context)
    
    Returns:
    
    true if the expression node will allow setValue()
    
    Throws:
    
    EvaluationException - if something went wrong trying to determine if the node supports writing
  - setValue
```
public void setValue(ExpressionState expressionState,
                     @Nullable
                     Object newValue)
              throws EvaluationException
```
    Description copied from interface: SpelNode
    
    Evaluate the expression to a node and then set the new value on that node. For example, if the expression evaluates to a property reference, then the property will be set to the new value.
    
    Specified by:
    
    setValue in interface SpelNode
    
    Parameters:
    
    expressionState - the current expression state (includes the context)
    
    newValue - the new value
    
    Throws:
    
    EvaluationException - if any problem occurs evaluating the expression or setting the new value
  - getChild
```
public SpelNode getChild(int index)
```
    Description copied from interface: SpelNode
    
    Helper method that returns a SpelNode rather than an Antlr Tree node.
    
    Specified by:
    
    getChild in interface SpelNode
    
    Returns:
    
    the child node cast to a SpelNode
  - getChildCount
```
public int getChildCount()
```
    Description copied from interface: SpelNode
    
    Return the number of children under this node.
    
    Specified by:
    
    getChildCount in interface SpelNode
    
    Returns:
    
    the child count
  - getObjectClass
```
@Nullable
public Class<?> getObjectClass(@Nullable
                                         Object obj)
```
    Description copied from interface: SpelNode
    
    Determine the class of the object passed in, unless it is already a class object.
    
    Specified by:
    
    getObjectClass in interface SpelNode
    
    Parameters:
    
    obj - the object that the caller wants the class of
    
    Returns:
    
    the class of the object if it is not already a class object, or null if the object is null
  - getStartPosition
```
public int getStartPosition()
```
    Description copied from interface: SpelNode
    
    Return the start position of this AST node in the expression string.
    
    Specified by:
    
    getStartPosition in interface SpelNode
    
    Returns:
    
    the start position
  - getEndPosition
```
public int getEndPosition()
```
    Description copied from interface: SpelNode
    
    Return the end position of this AST node in the expression string.
    
    Specified by:
    
    getEndPosition in interface SpelNode
    
    Returns:
    
    the end position
  - isCompilable
```
public boolean isCompilable()
```
    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.
    
    Returns:
    
    true if this node can be compiled to bytecode
  - generateCode
```
public void generateCode(MethodVisitor mv,
                         CodeFlow cf)
```
    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.
    
    Parameters:
    
    mv - the ASM MethodVisitor into which code should be generated
    
    cf - a context object with info about what is on the stack
  - getExitDescriptor
```
@Nullable
public String getExitDescriptor()
```
  - getValue
```
@Nullable
protected final <T> T getValue(ExpressionState state,
                                         Class<T> desiredReturnType)
                                  throws EvaluationException
```
    Throws:
    
    EvaluationException
  - getValueRef
```
protected ValueRef getValueRef(ExpressionState state)
                        throws EvaluationException
```
    Throws:
    
    EvaluationException
  - getValueInternal
```
public abstract TypedValue getValueInternal(ExpressionState expressionState)
                                     throws EvaluationException
```
    Throws:
    
    EvaluationException
  - generateCodeForArguments
```
protected static void generateCodeForArguments(MethodVisitor mv,
                                               CodeFlow cf,
                                               Member member,
                                               SpelNodeImpl[] arguments)
```
    Generate code that handles building the argument values for the specified method. This method will take account of whether the invoked method is a varargs method and if it is then the argument values will be appropriately packaged into an array.
    
    Parameters:
    
    mv - the method visitor where code should be generated
    
    cf - the current codeflow
    
    member - the method or constructor for which arguments are being setup
    
    arguments - the expression nodes for the expression supplied argument values
  - generateCodeForArgument
```
protected static void generateCodeForArgument(MethodVisitor mv,
                                              CodeFlow cf,
                                              SpelNodeImpl argument,
                                              String paramDesc)
```
    Ask an argument to generate its bytecode and then follow it up with any boxing/unboxing/checkcasting to ensure it matches the expected parameter descriptor.

Class SpelNodeImpl

Field Summary

Fields inherited from interface org.springframework.asm.Opcodes

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.springframework.expression.spel.SpelNode

Field Detail

children

exitTypeDescriptor

Constructor Detail

SpelNodeImpl

Method Detail

nextChildIs

getValue

getTypedValue

isWritable

setValue

getChild

getChildCount

getObjectClass

getStartPosition

getEndPosition

isCompilable

generateCode

getExitDescriptor

getValue

getValueRef

getValueInternal

generateCodeForArguments

generateCodeForArgument