How to use

getSourceCRS

method

in

org.apache.sis.referencing.operation.DefaultConversion

/**
 * Returns the source CRS, which must be geographic or {@code null}.
 */
@Override
public final GeographicCRS getSourceCRS() {
  return (GeographicCRS) super.getSourceCRS();
}

/**
 * Returns the source CRS, which must be geographic or {@code null}.
 */
@Override
public final GeographicCRS getSourceCRS() {
  return (GeographicCRS) super.getSourceCRS();
}

/**
 * Creates a dummy derived CRS defined by a longitude rotation from Paris to Greenwich prime meridian,
 * and swapping the axis order. The result is equivalent to {@link HardCodedCRS#WGS84_φλ},
 * which of course makes the returned {@code DerivedCRS} totally useless.
 * Its purpose is only to perform easy tests.
 */
private static DefaultDerivedCRS createLongitudeRotation() {
  final DefaultConversion conversion = DefaultConversionTest.createLongitudeRotation(false);
  return new DefaultDerivedCRS(Collections.singletonMap(DefaultDerivedCRS.NAME_KEY, conversion.getTargetCRS().getName()),
      (SingleCRS) conversion.getSourceCRS(), conversion, HardCodedCS.GEODETIC_φλ);
}

assertSame(op, op.specialize(Conversion.class, op.getSourceCRS(), op.getTargetCRS(), factory));
op = op.specialize(DefaultConversion.class, op.getSourceCRS(),
    changeCS(op.getTargetCRS(), HardCodedCS.GEODETIC_φλ), factory);
assertMatrixEquals("Longitude rotation of a two-dimensional CRS", Matrices.create(3, 4, new double[] {

assertNull("sourceCRS", definingConversion.getSourceCRS());
assertNull("targetCRS", definingConversion.getTargetCRS());
assertFalse(definingConversion.equals(reference));
    changeCS(reference.getSourceCRS(), HardCodedCS.GEODETIC_φλ),
    reference.getTargetCRS(),
    DefaultFactories.forBuildin(MathTransformFactory.class));

assertNull("sourceCRS",        c.getSourceCRS());
assertNull("targetCRS",        c.getTargetCRS());
assertNull("interpolationCRS", c.getInterpolationCRS());

op.getSourceCRS(),          // Keep the same source CRS.

/**
 * Asserts that at least some of the properties of the given {@code op} instance have the expected values
 * for an instance created by {@link #createLongitudeRotation(GeographicCRS, GeographicCRS, TemporalCRS)}.
 */
@SuppressWarnings("SuspiciousToArrayCall")
private static void verifyProperties(final DefaultConversion op, final boolean swapSourceAxes) {
  assertEquals("name",       "Paris to Greenwich", op.getName().getCode());
  assertEquals("sourceCRS",  "NTF (Paris)",        op.getSourceCRS().getName().getCode());
  assertEquals("targetCRS",  "Back to Greenwich",  op.getTargetCRS().getName().getCode());
  assertEquals("method",     "Longitude rotation", op.getMethod().getName().getCode());
  assertEquals("parameters", "Longitude rotation", op.getParameterDescriptors().getName().getCode());
  final ParameterValueGroup parameters = op.getParameterValues();
  final ParameterValue<?>[] values = parameters.values().toArray(new ParameterValue<?>[1]);
  assertEquals("parameters",    "Longitude rotation", parameters.getDescriptor().getName().getCode());
  assertEquals("parameters[0]", "Longitude offset",    values[0].getDescriptor().getName().getCode());
  assertEquals("parameters[0]", OFFSET, values[0].doubleValue(), STRICT);
  assertEquals(1, values.length);
  final Matrix3 expected = new Matrix3();
  expected.m02 = OFFSET;
  if (swapSourceAxes) {
    expected.m00 = expected.m11 = 0;
    expected.m01 = expected.m10 = 1;
  }
  assertMatrixEquals("Longitude rotation of a two-dimensional CRS", expected,
      MathTransforms.getMatrix(op.getMathTransform()), STRICT);
}