BluePortCandidateProvider.java

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package input.portcandidateprovider;

import com.yworks.yfiles.graph.IGraph;
import com.yworks.yfiles.graph.INode;
import com.yworks.yfiles.graph.portlocationmodels.FreeNodePortLocationModel;
import com.yworks.yfiles.view.input.AbstractPortCandidateProvider;
import com.yworks.yfiles.view.input.DefaultPortCandidate;
import com.yworks.yfiles.view.input.IInputModeContext;
import com.yworks.yfiles.view.input.IPortCandidate;
import com.yworks.yfiles.view.input.PortCandidateValidity;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * This port candidate provider returns a list of port candidates that are
 * the equivalent to the node's pre-defined ports. Only candidates of
 * unconnected ports are valid, i.e. if a port already has a connected edge, its
 * port candidate is marked as invalid.
 */
class BluePortCandidateProvider extends AbstractPortCandidateProvider {

  private final INode node;

  BluePortCandidateProvider(INode node) {
    this.node = node;
  }


  /**
   * Returns an enumeration that contains one port candidate for each of the node's pre-defined
   * ports. Each candidate has the same location as the port. Only candidates of
   * unconnected ports are valid, i.e. if a port already has a connected
   * edge, its port candidate is marked as invalid.
   * <p>
   *   Note that the various variants of getPortCandidates of
   *   {@link AbstractPortCandidateProvider} delegate to this method. This can be
   *   used to provide the same candidates for all use-cases.
   * </p>
   */
  @Override
  protected Iterable<IPortCandidate> getPortCandidates(IInputModeContext context) {
    List<IPortCandidate> candidates = new ArrayList<>();
    IGraph graph = context.getGraph();
    if (graph != null) {
      // create a port candidate for each port on the node
      List<DefaultPortCandidate> defaultPortCandidates = node.getPorts().stream().map(DefaultPortCandidate::new).collect(Collectors.toList());
      // per default, a DefaultPortCandidate is valid. we want to make those candidates with ports that have already edges connected to them to be invalid.
      defaultPortCandidates.stream()
          .filter(portCandidate -> graph.degree(portCandidate.getPort()) > 0)
          .forEach(portCandidate -> portCandidate.setValidity(PortCandidateValidity.INVALID));
      candidates.addAll(defaultPortCandidates);
    }
    if (candidates.isEmpty()) {
      // if there a no candidates at all, we create a fallback candidate in the middle of the node
      DefaultPortCandidate item = new DefaultPortCandidate(node, FreeNodePortLocationModel.NODE_CENTER_ANCHORED);
      item.setValidity(PortCandidateValidity.INVALID);
      candidates.add(item);
    }
    return candidates;
  }
}