/*
 * Copyright 2015 the original author or authors.
 *
 * 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.gradle.tooling.events;

import org.gradle.api.Incubating;
import org.gradle.api.Nullable;

/**
 * Describes an operation for which an event has occurred.
 *
 * <p>You can use {@code equals()} to determine whether 2 different descriptors refer to the same operation.</p>
 *
 * @since 2.4
 */
@Incubating
public interface OperationDescriptor {

    /**
     * Descriptor that is set when a reference to an operation cannot be resolved. This only happens when an operation points to a parent operation and the parent operation is unknown because the
     * events for that operation have not been registered to listen for.
     */
    OperationDescriptor UNKNOWN = new OperationDescriptor() {
        @Override
        public String getName() {
            return "unknown";
        }

        @Override
        public String getDisplayName() {
            return "descriptor not found";
        }

        @Nullable
        @Override
        public OperationDescriptor getParent() {
            return null;
        }
    };

    /**
     * Returns the name of the operation. This name does not necessarily uniquely identify the operation.
     *
     * @return The name of the operation.
     */
    String getName();

    /**
     * Returns a human consumable display name for the operation.
     *
     * @return The display name of the operation.
     */
    String getDisplayName();

    /**
     * Returns the parent operation, if any.
     *
     * @return The parent operation.
     */
    @Nullable
    OperationDescriptor getParent();

}

@@ -1636,16 +1636,117 @@
        %7D
+%0A%0A        @Override%0A        public String toString() %7B%0A            return getDisplayName();%0A        %7D
 %0A    %7D;%0A

Implement toString