Update (2025-08-31): Clarify the scope and implementation plan. - We will keep the original method isNumeric(String, boolean) behavior unchanged (signed inputs still fail). - Add a new overload: isNumeric(String str, boolean allowDot, boolean allowSign). - The old method will delegate to the new one with allowSign = false. - Unit tests will include regression checks for the old method and new tests for signed numbers.

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Apache Dubbo Component

Java SDK (apache/dubbo)

Descriptions

Summary

Add an overload StringUtils.isNumeric(String str, boolean allowDot, boolean allowSign) to optionally allow a single leading + or - while keeping the existing API and behavior unchanged.

Motivation

Some call sites need to accept signed integers/decimals (e.g., -1, +1.23). The current isNumeric(String, boolean allowDot) rejects any leading sign, which leads to ad-hoc checks or rejecting valid inputs. Centralizing this logic in StringUtils reduces duplication and avoids subtle bugs.

Proposed change

  • Introduce isNumeric(String, boolean allowDot, boolean allowSign).
  • When allowSign == true, accept exactly one leading sign at index 0.
  • A lone sign ("+" or "-") remains invalid.
  • Dot rule unchanged: at most one dot if allowDot == true; otherwise any dot fails.
  • Whitespace is not trimmed: any whitespace causes false.
  • Only ASCII digits are recognized; no scientific notation or locale digits.

Non-goals

  • Do not change the semantics of the existing isNumeric(String, boolean).
  • Do not support scientific notation (1e3) or locale-specific numerals.
  • Do not add parsing/normalization (e.g., no trimming or BigDecimal parsing).

Compatibility

  • Strictly backward compatible: the original method and its semantics remain intact; existing callers observe no behavior change.

Affected component

  • Module: dubbo-common
  • Class: org.apache.dubbo.common.utils.StringUtils

Test plan / Acceptance criteria

Add unit tests covering: - Signed and unsigned integers/decimals: - "-1" → pass only when allowSign == true - "+1.23" → pass only when allowDot && allowSign - Lone sign: "+", "-" → always false - Multiple dots: "1.2.3" → false - Non-digit characters: "12a", "--1", "+-1" → false - Whitespace: " 1", "1 " → false - Null / empty: null, "" → false - Regression: the original method still returns false for "-1" / "+1.23"

CI note

Run mvn -q -pl dubbo-common -am test in a networked environment so the parent POM and dependencies can be resolved.

Related issues

None found after searching for “StringUtils.isNumeric” / “allow sign” / “signed number”. This issue will be referenced by the upcoming PR.

Are you willing to submit a pull request to fix on your own?

  • [x] Yes I am willing to submit a pull request on my own!

Code of Conduct