Define ResourceReader interface for reading data from a resource identified by a Resource handle.

Ressolves gh-92.

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);
+	}
+}