Class Selection

java.lang.Object
org.springframework.expression.spel.ast.SpelNodeImpl
org.springframework.expression.spel.ast.Selection
All Implemented Interfaces:
org.springframework.asm.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 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, V25, V26, 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 SpelNodeImpl

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

    Methods inherited from class Object

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

    Methods inherited from interface SpelNode

    generateCode, isCompilable