/*
 * Copyright 2002-2020 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
 *
 *      https://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.springframework.core.metrics;

import java.util.Collections;
import java.util.Iterator;
import java.util.function.Supplier;

/**
 * Default "no op" {@code ApplicationStartup} implementation.
 *
 * <p>This variant is designed for minimal overhead and does not record events.
 *
 * @author Brian Clozel
 */
class DefaultApplicationStartup implements ApplicationStartup {

	@Override
	public DefaultStartupStep start(String name) {
		return new DefaultStartupStep();
	}


	static class DefaultStartupStep implements StartupStep {

		boolean recorded = false;

		private final DefaultTags TAGS = new DefaultTags();

		@Override
		public String getName() {
			return "default";
		}

		@Override
		public long getId() {
			return 0L;
		}

		@Override
		public Long getParentId() {
			return null;
		}

		@Override
		public Tags getTags() {
			return this.TAGS;
		}

		@Override
		public StartupStep tag(String key, String value) {
			if (this.recorded) {
				throw new IllegalArgumentException();
			}
			return this;
		}

		@Override
		public StartupStep tag(String key, Supplier<String> value) {
			if (this.recorded) {
				throw new IllegalArgumentException();
			}
			return this;
		}

		@Override
		public void end() {
			this.recorded = true;
		}


		static class DefaultTags implements StartupStep.Tags {

			@Override
			public Iterator<StartupStep.Tag> iterator() {
				return Collections.emptyIterator();
			}
		}
	}

}

@@ -17,17 +17,17 @@
 2002-202
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  the ori
@@ -998,16 +998,107 @@
 rtup %7B%0A%0A
+%09private static final DefaultStartupStep DEFAULT_STARTUP_STEP = new DefaultStartupStep();%0A%0A
 %09@Overri
@@ -1100,16 +1100,16 @@
 verride%0A
-
 %09public 
@@ -1161,32 +1161,28 @@
 urn 
-new DefaultStartupStep()
+DEFAULT_STARTUP_STEP
 ;%0A%09%7D
@@ -1247,37 +1247,8 @@
  %7B%0A%0A
-%09%09boolean recorded = false;%0A%0A
 %09%09pr
@@ -1615,79 +1615,8 @@
 ) %7B%0A
-%09%09%09if (this.recorded) %7B%0A%09%09%09%09throw new IllegalArgumentException();%0A%09%09%09%7D%0A
 %09%09%09r
@@ -1711,79 +1711,8 @@
 ) %7B%0A
-%09%09%09if (this.recorded) %7B%0A%09%09%09%09throw new IllegalArgumentException();%0A%09%09%09%7D%0A
 %09%09%09r
@@ -1766,32 +1766,8 @@
 ) %7B%0A
-%09%09%09this.recorded = true;
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Return static DefaultApplicationStartup step