Package org.springframework.expression.spel.ast

Class Selection

java.lang.Object

org.springframework.expression.spel.ast.SpelNodeImpl

org.springframework.expression.spel.ast.Selection

All Implemented Interfaces:

Opcodes, SpelNode

public class Selection
extends SpelNodeImpl

Represents selection over a Map, Iterable, or array.

For example, {1,2,3,4,5,6,7,8,9,10}.?[#isEven(#this)] evaluates to [2, 4, 6, 8, 10].

Basically a subset of the input data is returned based on the evaluation of the expression supplied as selection criteria.

Null-safe Selection

Null-safe selection is supported via the '?.?' operator. For example, 'names?.?[#this.length > 5]' will evaluate to null if names is null and will otherwise evaluate to a sequence containing the names whose length is greater than 5. As of Spring Framework 7.0, null-safe selection also applies when performing selection on an Optional target. For example, if names is of type Optional<List<String>>, the expression 'names?.?[#this.length > 5]' will evaluate to null if names is null or empty and will otherwise evaluate to a sequence containing the names whose lengths are greater than 5, effectively names.get().stream().filter(s -> s.length() > 5).toList().

Since:

3.0

Author:

Andy Clement, Mark Fisher, Sam Brannen, Juergen Hoeller

Field Summary

Fields

Modifier and Type	Field	Description
static final int	ALL	All items (?[]).
static final int	FIRST	The first item (^[]).
static final int	LAST	The last item ($[]).

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

children, exitTypeDescriptor

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_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, ASM10_EXPERIMENTAL, ASM4, ASM5, ASM6, ASM7, ASM8, ASM9, 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, V16, V17, V18, V19, V20, V21, V22, V23, V24, V9

Constructor Summary

Constructors

Constructor	Description
Selection(boolean nullSafe, int variant, int startPos, int endPos, SpelNodeImpl expression)

Method Summary

Modifier and Type	Method	Description
TypedValue	getValueInternal(ExpressionState state)
protected ValueRef	getValueRef(ExpressionState state)
final boolean	isNullSafe()	Does this node represent a null-safe selection operation?
String	toStringAST()	Return the string form of this AST node.

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

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

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

generateCode, isCompilable

Field Details

ALL

public static final int ALL

All items (?[]).

See Also:

• Constant Field Values

FIRST

public static final int FIRST

The first item (^[]).

See Also:

• Constant Field Values

LAST

public static final int LAST

The last item ($[]).

See Also:

• Constant Field Values

Constructor Details

Selection

public Selection(boolean nullSafe,
 int variant,
 int startPos,
 int endPos,
 SpelNodeImpl expression)

Method Details

isNullSafe

public final boolean isNullSafe()

Does this node represent a null-safe selection operation?

Overrides:

isNullSafe in class SpelNodeImpl

Returns:

true if this node is the target of a null-safe operation

Since:

6.1.6

getValueInternal

public TypedValue getValueInternal(ExpressionState state)
                            throws EvaluationException

Specified by:

getValueInternal in class SpelNodeImpl

Throws:

EvaluationException

getValueRef

protected ValueRef getValueRef(ExpressionState state)
                        throws EvaluationException

Overrides:

getValueRef in class SpelNodeImpl

Throws:

EvaluationException

toStringAST

public String toStringAST()

Description copied from interface: SpelNode

Return the string form of this AST node.

Returns:

the string form