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 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you 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.elasticsearch.action.support;

import org.elasticsearch.action.ActionListener;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.test.ESTestCase;

import java.io.IOException;

public class ContextPreservingActionListenerTests extends ESTestCase {

    public void testOriginalContextIsPreservedAfterOnResponse() throws IOException {
        try (ThreadContext threadContext = new ThreadContext(Settings.EMPTY)) {
            final boolean nonEmptyContext = randomBoolean();
            if (nonEmptyContext) {
                threadContext.putHeader("not empty", "value");
            }
            final ContextPreservingActionListener<Void> actionListener;
            try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
                threadContext.putHeader("foo", "bar");
                final ActionListener<Void> delegate = new ActionListener<Void>() {
                    @Override
                    public void onResponse(Void aVoid) {
                        assertEquals("bar", threadContext.getHeader("foo"));
                        assertNull(threadContext.getHeader("not empty"));
                    }

                    @Override
                    public void onFailure(Exception e) {
                        throw new RuntimeException("onFailure shouldn't be called", e);
                    }
                };
                if (randomBoolean()) {
                    actionListener = new ContextPreservingActionListener<>(threadContext.newRestorableContext(true), delegate);
                } else {
                    actionListener = ContextPreservingActionListener.wrapPreservingContext(delegate, threadContext);
                }
            }

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));

            actionListener.onResponse(null);

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));
        }
    }

    public void testOriginalContextIsPreservedAfterOnFailure() throws Exception {
        try (ThreadContext threadContext = new ThreadContext(Settings.EMPTY)) {
            final boolean nonEmptyContext = randomBoolean();
            if (nonEmptyContext) {
                threadContext.putHeader("not empty", "value");
            }
            final ContextPreservingActionListener<Void> actionListener;
            try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
                threadContext.putHeader("foo", "bar");
                final ActionListener<Void> delegate = new ActionListener<Void>() {
                    @Override
                    public void onResponse(Void aVoid) {
                        throw new RuntimeException("onResponse shouldn't be called");
                    }

                    @Override
                    public void onFailure(Exception e) {
                        assertEquals("bar", threadContext.getHeader("foo"));
                        assertNull(threadContext.getHeader("not empty"));
                    }
                };

                if (randomBoolean()) {
                    actionListener = new ContextPreservingActionListener<>(threadContext.newRestorableContext(true), delegate);
                } else {
                    actionListener = ContextPreservingActionListener.wrapPreservingContext(delegate, threadContext);
                }

            }

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));

            actionListener.onFailure(null);

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));
        }
    }

    public void testOriginalContextIsWhenListenerThrows() throws Exception {
        try (ThreadContext threadContext = new ThreadContext(Settings.EMPTY)) {
            final boolean nonEmptyContext = randomBoolean();
            if (nonEmptyContext) {
                threadContext.putHeader("not empty", "value");
            }
            final ContextPreservingActionListener<Void> actionListener;
            try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
                threadContext.putHeader("foo", "bar");
                final ActionListener<Void> delegate = new ActionListener<Void>() {
                    @Override
                    public void onResponse(Void aVoid) {
                        assertEquals("bar", threadContext.getHeader("foo"));
                        assertNull(threadContext.getHeader("not empty"));
                        throw new RuntimeException("onResponse called");
                    }

                    @Override
                    public void onFailure(Exception e) {
                        assertEquals("bar", threadContext.getHeader("foo"));
                        assertNull(threadContext.getHeader("not empty"));
                        throw new RuntimeException("onFailure called");
                    }
                };

                if (randomBoolean()) {
                    actionListener = new ContextPreservingActionListener<>(threadContext.newRestorableContext(true), delegate);
                } else {
                    actionListener = ContextPreservingActionListener.wrapPreservingContext(delegate, threadContext);
                }
            }

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));

            RuntimeException e = expectThrows(RuntimeException.class, () -> actionListener.onResponse(null));
            assertEquals("onResponse called", e.getMessage());

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));

            e = expectThrows(RuntimeException.class, () -> actionListener.onFailure(null));
            assertEquals("onFailure called", e.getMessage());

            assertNull(threadContext.getHeader("foo"));
            assertEquals(nonEmptyContext ? "value" : null, threadContext.getHeader("not empty"));
        }
    }
}