[BUG] AbstractCategoryItemLabelGenerator.equals() ignores percentFormat while hashCode() includes it.

[OldTruckDriver]

Summary

AbstractCategoryItemLabelGenerator.equals(Object) does not compare percentFormat, but hashCode() includes it. This means two generators with different percent formatters can compare equal while producing different labels. nullValueString has the same situation.

Affected code

File: src/main/java/org/jfree/chart/labels/AbstractCategoryItemLabelGenerator.java

private final NumberFormat percentFormat;

@Override
public boolean equals(Object obj) {
    if (obj == this) {
        return true;
    }
    if (!(obj instanceof AbstractCategoryItemLabelGenerator)) {
        return false;
    }

    AbstractCategoryItemLabelGenerator<R, C> that
        = (AbstractCategoryItemLabelGenerator<R, C>) obj;
    if (!this.labelFormat.equals(that.labelFormat)) {
        return false;
    }
    if (!Objects.equals(this.dateFormat, that.dateFormat)) {
        return false;
    }
    if (!Objects.equals(this.numberFormat, that.numberFormat)) {
        return false;
    }
    return true;
}

@Override
public int hashCode() {
    int result = 127;
    result = HashUtils.hashCode(result, this.labelFormat);
    result = HashUtils.hashCode(result, this.nullValueString);
    result = HashUtils.hashCode(result, this.dateFormat);
    result = HashUtils.hashCode(result, this.numberFormat);
    result = HashUtils.hashCode(result, this.percentFormat);
    return result;
}

Reproducer

Add the following test to src/test/java/org/jfree/chart/labels/StandardCategoryItemLabelGeneratorTest.java:

@Test
public void testEqualsDifferentPercentFormat() {
    StandardCategoryItemLabelGenerator g1
            = new StandardCategoryItemLabelGenerator("{2}",
            new DecimalFormat("0.000"), new DecimalFormat("0.0%"));
    StandardCategoryItemLabelGenerator g2
            = new StandardCategoryItemLabelGenerator("{2}",
            new DecimalFormat("0.000"), new DecimalFormat("0.00%"));
    assertNotEquals(g1, g2);
}

Run:

mvn -q -Dtest=org.jfree.chart.labels.StandardCategoryItemLabelGeneratorTest test

Observed behavior

StandardCategoryItemLabelGeneratorTest.testEqualsDifferentPercentFormat:125
expected: not equal but was: <org.jfree.chart.labels.StandardCategoryItemLabelGenerator@...>

Expected behavior

Objects with different percentFormat values should not compare equal.

Why this is a bug

• percentFormat affects the rendered item label text.
• equals() ignores it.
• hashCode() includes it.

So the current implementation violates both semantic equality and the equals/hashCode contract.