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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  package org.apache.commons.geometry.euclidean.twod;
    18
    19  import java.util.Iterator;
    20  import java.util.stream.Stream;
    21
    22  /** Class used to construct {@link Bounds2D} instances representing the min and
    23   * max points present in a {@link BoundarySource2D}. The implementation examines
    24   * the vertices of each boundary in turn. Null is returned if any boundaries are
    25   * infinite or no vertices are present.
    26   */
    27  final class BoundarySourceBoundsBuilder2D {
    28
    29      /** Get a {@link Bounds2D} instance containing all vertices in the given boundary source.
    30       * Null is returned if any encountered boundaries were not finite or no vertices were found.
    31       * @param src boundary source to compute the bounds of
    32       * @return the bounds of the argument or null if no valid bounds could be determined
    33       */
    34      public Bounds2D getBounds(final BoundarySource2D src) {
    35
    36          final Bounds2D.Builder builder = Bounds2D.builder();
    37
    38          try (Stream<LineConvexSubset> stream = src.boundaryStream()) {
    39              final Iterator<LineConvexSubset> it = stream.iterator();
    40
    41              LineConvexSubset boundary;
    42              while (it.hasNext()) {
    43                  boundary = it.next();
    44
    45                  if (boundary.isInfinite()) {
    46                      return null; // break out early
    47                  }
    48
    49                  builder.add(boundary.getStartPoint());
    50                  builder.add(boundary.getEndPoint());
    51              }
    52          }
    53
    54          return builder.hasBounds() ?
    55                  builder.build() :
    56                  null;
    57      }
    58  }