diff --git a/spring-geode/src/main/java/org/springframework/geode/core/io/ResourceReader.java b/spring-geode/src/main/java/org/springframework/geode/core/io/ResourceReader.java new file mode 100644 index 00000000..23d6bdcb --- /dev/null +++ b/spring-geode/src/main/java/org/springframework/geode/core/io/ResourceReader.java @@ -0,0 +1,87 @@ +/* + * Copyright 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.geode.core.io; + +import java.nio.ByteBuffer; + +import org.springframework.core.io.Resource; +import org.springframework.lang.NonNull; +import org.springframework.lang.Nullable; + +/** + * Interface (contract) for readers to define the algorithm and strategy for reading data from a {@link Resource}, + * such as by using the {@link Resource Resource's} {@link Resource#getInputStream() InputStream}. + * + * @author John Blum + * @see java.nio.ByteBuffer + * @see org.springframework.core.io.Resource + * @since 1.3.1 + */ +@FunctionalInterface +@SuppressWarnings("unused") +public interface ResourceReader { + + /** + * Reads data from the {@literal non-null} {@link Resource} into a byte array. + * + * This method should throw an {@link UnhandledResourceException} if the algorithm and strategy used by this reader + * is not able to or capable of reading from the {@link Resource} at its location. This allows subsequent readers + * in a composition to possibly handle the {@link Resource}. Any other {@link Throwable} thrown by this {@code read} + * method will break the chain of read calls in the composition. + * + * @param resource {@link Resource} to read data from. + * @return a {@literal non-null} byte array containing the data from the {@link Resource}. + * @see org.springframework.core.io.Resource + */ + @NonNull byte[] read(@NonNull Resource resource); + + /** + * Reads data from the {@literal non-null} {@link Resource} into a {@link ByteBuffer}. + * + * @param resource {@link Resource} to read data from. + * @return a {@literal non-null} {@link ByteBuffer} containing the data from the {@link Resource}. + * @see org.springframework.core.io.Resource + * @see java.nio.ByteBuffer + * @see #read(Resource) + */ + default @NonNull ByteBuffer readIntoByteBuffer(@NonNull Resource resource) { + return ByteBuffer.wrap(read(resource)); + } + + /** + * Composes this {@link ResourceReader} with the given {@link ResourceReader} + * using the {@literal Composite Software Design Pattern}. + * + * @param reader {@link ResourceReader} to compose with this reader. + * @return a composite {@link ResourceReader} composed of this {@link ResourceReader} + * and the given {@link ResourceReader}. If the given {@link ResourceReader} is {@literal null}, + * then this {@link ResourceReader} is returned. + * @see Compsite Software Design Pattern + * @see ResourceReader + */ + default @NonNull ResourceReader thenReadFrom(@Nullable ResourceReader reader) { + + return reader == null ? this + : resource -> { + try { + return this.read(resource); + } + catch (UnhandledResourceException ignore) { + return reader.read(resource); + } + }; + } +} diff --git a/spring-geode/src/test/java/org/springframework/geode/core/io/ResourceReaderUnitTests.java b/spring-geode/src/test/java/org/springframework/geode/core/io/ResourceReaderUnitTests.java new file mode 100644 index 00000000..fddcc4c4 --- /dev/null +++ b/spring-geode/src/test/java/org/springframework/geode/core/io/ResourceReaderUnitTests.java @@ -0,0 +1,141 @@ +/* + * Copyright 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.geode.core.io; + +import static org.assertj.core.api.Assertions.assertThat; +import static org.mockito.ArgumentMatchers.any; +import static org.mockito.ArgumentMatchers.eq; +import static org.mockito.Mockito.doCallRealMethod; +import static org.mockito.Mockito.doReturn; +import static org.mockito.Mockito.doThrow; +import static org.mockito.Mockito.mock; +import static org.mockito.Mockito.never; +import static org.mockito.Mockito.times; +import static org.mockito.Mockito.verify; +import static org.mockito.Mockito.verifyNoInteractions; + +import java.nio.ByteBuffer; + +import org.junit.Test; + +import org.springframework.core.io.Resource; + +/** + * Unit Tests for {@link ResourceReader}. + * + * @author John Blum + * @see java.nio.ByteBuffer + * @see org.junit.Test + * @see org.mockito.Mockito + * @see org.springframework.core.io.Resource + * @see org.springframework.geode.core.io.ResourceReader + * @since 1.3.1 + */ +public class ResourceReaderUnitTests { + + @Test + public void readIntoByteBufferCallsRead() { + + byte[] array = { (byte) 0xCA, (byte) 0xFE, (byte) 0xBA, (byte) 0xBE }; + + Resource mockResource = mock(Resource.class); + + ResourceReader mockResourceReader = mock(ResourceReader.class); + + doReturn(array).when(mockResourceReader).read(eq(mockResource)); + doCallRealMethod().when(mockResourceReader).readIntoByteBuffer(any()); + + ByteBuffer byteBuffer = mockResourceReader.readIntoByteBuffer(mockResource); + + assertThat(byteBuffer).isNotNull(); + assertThat(byteBuffer.array()).isEqualTo(array); + + verify(mockResourceReader, times(1)).read(eq(mockResource)); + verifyNoInteractions(mockResource); + } + + @Test + public void thenReadFromNullReturnsThis() { + + ResourceReader mockResourceReader = mock(ResourceReader.class); + + doCallRealMethod().when(mockResourceReader).thenReadFrom(any()); + + assertThat(mockResourceReader.thenReadFrom(null)).isEqualTo(mockResourceReader); + } + + @Test + public void thenReadFromResourceReaderReturnsComposite() { + + ResourceReader thisMockResourceReader = mock(ResourceReader.class, "this"); + ResourceReader thatMockResourceReader = mock(ResourceReader.class, "that"); + + doCallRealMethod().when(thisMockResourceReader).thenReadFrom(any()); + + ResourceReader composite = thisMockResourceReader.thenReadFrom(thatMockResourceReader); + + assertThat(composite).isNotNull(); + assertThat(composite).isNotEqualTo(thisMockResourceReader); + assertThat(composite).isNotEqualTo(thatMockResourceReader); + } + + @Test + public void thenReadFromResourceReaderReadsFromThis() { + + byte[] array = { (byte) 0xBA, (byte) 0xBE }; + + Resource mockResource = mock(Resource.class); + + ResourceReader thisMockResourceReader = mock(ResourceReader.class, "this"); + ResourceReader thatMockResourceReader = mock(ResourceReader.class, "that"); + + doCallRealMethod().when(thisMockResourceReader).thenReadFrom(any()); + doReturn(array).when(thisMockResourceReader).read(eq(mockResource)); + + ResourceReader composite = thisMockResourceReader.thenReadFrom(thatMockResourceReader); + + assertThat(composite).isNotNull(); + assertThat(composite.read(mockResource)).isEqualTo(array); + + verify(thisMockResourceReader, times(1)).read(eq(mockResource)); + verify(thatMockResourceReader, never()).read(any()); + verifyNoInteractions(mockResource); + } + + @Test + public void thenReadFromResourceReaderReadsFromThat() { + + byte[] array = { (byte) 0xFA, (byte) 0xDE }; + + Resource mockResource = mock(Resource.class); + + ResourceReader thisMockResourceReader = mock(ResourceReader.class, "this"); + ResourceReader thatMockResourceReader = mock(ResourceReader.class, "that"); + + doCallRealMethod().when(thisMockResourceReader).thenReadFrom(any()); + doThrow(new UnhandledResourceException("TEST")).when(thisMockResourceReader).read(eq(mockResource)); + doReturn(array).when(thatMockResourceReader).read(eq(mockResource)); + + ResourceReader composite = thisMockResourceReader.thenReadFrom(thatMockResourceReader); + + assertThat(composite).isNotNull(); + assertThat(composite.read(mockResource)).isEqualTo(array); + + verify(thisMockResourceReader, times(1)).read(eq(mockResource)); + verify(thatMockResourceReader, times(1)).read(eq(mockResource)); + verifyNoInteractions(mockResource); + } +}