How to use

filter

method

in

org.apache.sis.internal.util.CollectionsExt

/**
 * Returns some map projection methods supported by {@literal Proj.4}.
 * Current implementation can not return the complete list of Proj.4 method, but returns the main ones.
 * For each operation method in the returned set, the Proj.4 projection name can be obtained as below:
 *
 * {@preformat java
 *     String proj = IdentifiedObjects.getName(method, Citations.PROJ4);
 * }
 *
 * The {@code proj} names obtained as above can be given in argument to the
 * {@link #getOperationMethod(String)} and {@link #getDefaultParameters(String)} methods.
 *
 * @param  type <code>{@linkplain SingleOperation}.class</code> for fetching all operation methods, or
 *              <code>{@linkplain Projection}.class</code> for fetching only map projection methods.
 * @return methods available in this factory for coordinate operations of the given type.
 *
 * @see org.apache.sis.referencing.operation.transform.DefaultMathTransformFactory#getAvailableMethods(Class)
 */
public Set<OperationMethod> getAvailableMethods(final Class<? extends SingleOperation> type) {
  return new LazySet<>(CollectionsExt.filter(mtFactory.getAvailableMethods(type).iterator(), Proj4Factory::isSupported));
}

/**
 * Returns some map projection methods supported by {@literal Proj.4}.
 * Current implementation can not return the complete list of Proj.4 method, but returns the main ones.
 * For each operation method in the returned set, the Proj.4 projection name can be obtained as below:
 *
 * {@preformat java
 *     String proj = IdentifiedObjects.getName(method, Citations.PROJ4);
 * }
 *
 * The {@code proj} names obtained as above can be given in argument to the
 * {@link #getOperationMethod(String)} and {@link #getDefaultParameters(String)} methods.
 *
 * @param  type <code>{@linkplain SingleOperation}.class</code> for fetching all operation methods, or
 *              <code>{@linkplain Projection}.class</code> for fetching only map projection methods.
 * @return methods available in this factory for coordinate operations of the given type.
 *
 * @see org.apache.sis.referencing.operation.transform.DefaultMathTransformFactory#getAvailableMethods(Class)
 */
public Set<OperationMethod> getAvailableMethods(final Class<? extends SingleOperation> type) {
  return new LazySet<>(CollectionsExt.filter(mtFactory.getAvailableMethods(type).iterator(), new Predicate<IdentifiedObject>() {
    @Override public boolean test(final IdentifiedObject method) {
      return isSupported(method);
    }
  }));
}

/**
 * Tests {@link CollectionsExt#filter(Iterator, Predicate)}.
 */
@Test
public void testFilter() {
  final Iterator<Integer> it = CollectionsExt.filter(Arrays.asList(2, 5, 7, 4, 8).iterator(), (Integer n) -> (n & 1) == 0);
  assertTrue  (   it.hasNext());
  assertEquals(2, it.next().intValue());
  assertEquals(4, it.next().intValue());
  assertTrue  (   it.hasNext());
  assertTrue  (   it.hasNext());
  assertEquals(8, it.next().intValue());
  assertFalse (   it.hasNext());
}