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Hi all,</div>
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I observed that a frequent pattern in class file transformation is that we test if a call matches given descriptors, and we subsequently replace it with a new call. For example, we might want to redirect calls to MethodHandle.Lookup to a proxy class that performs
run-time remapping of incoming class, method, or field names.</div>
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Currently, the best way to test for such call patterns is to examine their owner class, name, and type individually. For example, user would check:</div>
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owner.name().equalsString("java/lang/invoke/MethodHandles$Lookup")</div>
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Which has these problems:</div>
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<div class="elementToProof">Users might not be aware of this approach; they might do things like</div>
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<div class="elementToProof">owner.asInternalName().equals(...)</div>
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<div class="elementToProof">which will suffer from performance penalties due to the eager evaluation of internal names.</div>
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<div class="elementToProof">Users might get the internal name wrong, or confuse internal names with descriptors.</div>
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As a consequence, I propose addition of "equalsSymbol" method to these classes:</div>
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- ClassEntry::equalsSymbol(ClassDesc)</div>
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- MethodTypeEntry::equalsSymbol(MethodTypeDesc)</div>
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- ModuleEntry::equalsSymbol(ModuleDesc)</div>
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- PackageEntry::equalsSymbol(PackageDesc)</div>
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- StringEntry::equalsString(String)</div>
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- Utf8Entry::equalsSymbol(ClassDesc) // Might consider rename to "equalsTypeSymbol" to avoid confusion with ClassEntry?</div>
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- Utf8Entry::equalsSymbol(MethodTypeDesc)</div>
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With the following purposes:</div>
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<div class="elementToProof">To help such usages of descriptor matching tests to be less error-prone</div>
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<div class="elementToProof">To allow faster comparison with reduced processing on many constant pool entries</div>
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Please don't hesitate to share your thoughts about this proposal, such as renaming suggestions or problems with these new APIs.</div>
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Regards,</div>
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Chen Liang</div>
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