DeleteConnectorCommand.java

/*
 * Copyright 2017 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.kie.workbench.common.stunner.core.graph.command.impl;

import org.jboss.errai.common.client.api.annotations.MapsTo;
import org.jboss.errai.common.client.api.annotations.Portable;
import org.kie.workbench.common.stunner.core.command.CommandResult;
import org.kie.workbench.common.stunner.core.command.util.CommandUtils;
import org.kie.workbench.common.stunner.core.graph.Edge;
import org.kie.workbench.common.stunner.core.graph.Node;
import org.kie.workbench.common.stunner.core.graph.command.GraphCommandExecutionContext;
import org.kie.workbench.common.stunner.core.graph.content.view.View;
import org.kie.workbench.common.stunner.core.graph.content.view.ViewConnector;
import org.kie.workbench.common.stunner.core.rule.RuleViolation;
import org.uberfire.commons.validation.PortablePreconditions;

/**
 * A Command to delete an edge from a graph
 */
@Portable
public final class DeleteConnectorCommand extends AbstractGraphCompositeCommand {

    private final String edgeUUID;
    private transient Edge<? extends View, Node> edge;

    public DeleteConnectorCommand(final @MapsTo("edge") String edgeUUID) {
        this.edgeUUID = PortablePreconditions.checkNotNull("edgeUUID",
                                                           edgeUUID);
    }

    public DeleteConnectorCommand(final Edge<? extends View, Node> edge) {
        this(edge.getUUID());
        this.edge = edge;
    }

    @Override
    @SuppressWarnings("unchecked")
    protected DeleteConnectorCommand initialize(final GraphCommandExecutionContext context) {
        super.initialize(context);
        final Edge<? extends ViewConnector, Node> edge = getCandidateEdge(context);
        final Node<View<?>, Edge> targetNode = edge.getTargetNode();
        final Node<View<?>, Edge> sourceNode = edge.getSourceNode();
        if (null != sourceNode) {
            commands.add(new SetConnectionSourceNodeCommand(null,
                                                            edge));
        }
        if (null != targetNode) {
            commands.add(new SetConnectionTargetNodeCommand(null,
                                                            edge));
        }
        return this;
    }

    @Override
    public CommandResult<RuleViolation> execute(final GraphCommandExecutionContext context) {
        final CommandResult<RuleViolation> result = super.execute(context);
        if (!CommandUtils.isError(result)) {
            final Edge<? extends ViewConnector, Node> edge = getCandidateEdge(context);
            getMutableIndex(context).removeEdge(edge);
        }
        return result;
    }

    @Override
    public CommandResult<RuleViolation> undo(final GraphCommandExecutionContext context) {
        getMutableIndex(context).addEdge(edge);
        final CommandResult<RuleViolation> result = super.undo(context,
                                                               true);
        if (CommandUtils.isError(result)) {
            getMutableIndex(context).removeEdge(edge);
        }
        return result;
    }

    @SuppressWarnings("unchecked")
    private Edge<? extends ViewConnector, Node> getCandidateEdge(final GraphCommandExecutionContext context) {
        if (null == edge) {
            edge = getViewEdge(context,
                               edgeUUID);
        }
        return (Edge<? extends ViewConnector, Node>) edge;
    }

    public Edge<? extends View, Node> getEdge() {
        return edge;
    }

    @Override
    public String toString() {
        return getClass().getName() + "[edge=" + edgeUUID + "]";
    }

    @Override
    protected boolean delegateRulesContextToChildren() {
        return true;
    }
}