src/java.base/share/classes/jdk/internal/classfile/impl/NonterminalCodeBuilder.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package jdk.internal.classfile.impl;

import java.lang.classfile.CodeBuilder;
import java.lang.classfile.Label;
import java.lang.classfile.constantpool.ConstantPoolBuilder;

public abstract sealed class NonterminalCodeBuilder implements CodeBuilder
    permits ChainedCodeBuilder, BlockCodeBuilderImpl {
    protected final TerminalCodeBuilder terminal;
    protected final CodeBuilder parent;

    public NonterminalCodeBuilder(CodeBuilder parent) {
        this.parent = parent;
        this.terminal = findTerminal(parent);
    }

    static TerminalCodeBuilder findTerminal(CodeBuilder cob) {
        return cob instanceof NonterminalCodeBuilder ncb ?
                ncb.terminal : (TerminalCodeBuilder) cob;
    }

    @Override
    public int receiverSlot() {
        return terminal.receiverSlot();
    }

    @Override
    public int parameterSlot(int paramNo) {
        return terminal.parameterSlot(paramNo);
    }

    @Override
    public ConstantPoolBuilder constantPool() {
        return terminal.constantPool();
    }

    @Override
    public Label newLabel() {
        return terminal.newLabel();
    }
}