From d7f1091754e82f8ba7e902bf0bc7c4380443d93f Mon Sep 17 00:00:00 2001
From: John Blum <jblum@pivotal.io>
Date: Thu, 9 Jul 2020 17:08:29 -0700
Subject: [PATCH] Add null-safe isReadable(:Resource) and isWritable(:Resource)
 utility methods.

Resolve gh-92.
---
 .../geode/core/io/support/ResourceUtils.java  | 45 +++++++++---
 .../io/support/ResourceUtilsUnitTests.java    | 73 +++++++++++++++++++
 2 files changed, 108 insertions(+), 10 deletions(-)

diff --git a/spring-geode/src/main/java/org/springframework/geode/core/io/support/ResourceUtils.java b/spring-geode/src/main/java/org/springframework/geode/core/io/support/ResourceUtils.java
index 2bc576d2..131e15ba 100644
--- a/spring-geode/src/main/java/org/springframework/geode/core/io/support/ResourceUtils.java
+++ b/spring-geode/src/main/java/org/springframework/geode/core/io/support/ResourceUtils.java
@@ -34,6 +34,41 @@ import org.springframework.lang.Nullable;
  */
 public abstract class ResourceUtils {
 
+	/**
+	 * Determines whether the given byte array is {@literal null} or {@literal empty}.
+	 *
+	 * @param array byte array to evaluate.
+	 * @return a boolean value indicating whether the given byte array is {@literal null} or {@literal empty}.
+	 */
+	public static boolean isNotEmpty(@Nullable byte[] array) {
+		return array != null && array.length > 0;
+	}
+
+	/**
+	 * Null-safe operation to determine whether the given {@link Resource} is readable.
+	 *
+	 * @param resource {@link Resource} to evaluate.
+	 * @return a boolean value indicating whether the given {@link Resource} is readable.
+	 * @see org.springframework.core.io.Resource#isReadable()
+	 * @see org.springframework.core.io.Resource
+	 */
+	public static boolean isReadable(@Nullable Resource resource) {
+		return resource != null && resource.isReadable();
+	}
+
+	/**
+	 * Null-safe operation to determine whether the given {@link Resource} is writable.
+	 *
+	 * @param resource {@link Resource} to evaluate.
+	 * @return a boolean value indicating whether the given {@link Resource} is writable.
+	 * @see org.springframework.core.io.WritableResource#isWritable()
+	 * @see org.springframework.core.io.WritableResource
+	 * @see org.springframework.core.io.Resource
+	 */
+	public static boolean isWritable(@Nullable Resource resource) {
+		return resource instanceof WritableResource && ((WritableResource) resource).isWritable();
+	}
+
 	/**
 	 * Returns the {@link Resource} as a {@link WritableResource} if possible.
 	 *
@@ -56,16 +91,6 @@ public abstract class ResourceUtils {
 				ResourceUtils.nullSafeGetDescription(resource)));
 	}
 
-	/**
-	 * Determines whether the given byte array is {@literal null} or {@literal empty}.
-	 *
-	 * @param array byte array to evaluate.
-	 * @return a boolean value indicating whether the given byte array is {@literal null} or {@literal empty}.
-	 */
-	public static boolean isNotEmpty(@Nullable byte[] array) {
-		return array != null && array.length > 0;
-	}
-
 	/**
 	 * Null-safe method to get the {@link Resource#getDescription() description} of the given {@link Resource}.
 	 *
diff --git a/spring-geode/src/test/java/org/springframework/geode/core/io/support/ResourceUtilsUnitTests.java b/spring-geode/src/test/java/org/springframework/geode/core/io/support/ResourceUtilsUnitTests.java
index f5d98058..b45940c5 100644
--- a/spring-geode/src/test/java/org/springframework/geode/core/io/support/ResourceUtilsUnitTests.java
+++ b/spring-geode/src/test/java/org/springframework/geode/core/io/support/ResourceUtilsUnitTests.java
@@ -20,6 +20,7 @@ import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import org.junit.Test;
@@ -40,6 +41,78 @@ import org.springframework.core.io.WritableResource;
  */
 public class ResourceUtilsUnitTests {
 
+	@Test
+	public void isReadableWithReadableResourceReturnsTrue() {
+
+		Resource mockResource = mock(Resource.class);
+
+		doReturn(true).when(mockResource).isReadable();
+
+		assertThat(ResourceUtils.isReadable(mockResource)).isTrue();
+
+		verify(mockResource, times(1)).isReadable();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test
+	public void isReadableWithNonReadableResourceReturnsFalse() {
+
+		Resource mockResource = mock(Resource.class);
+
+		doReturn(false).when(mockResource).isReadable();
+
+		assertThat(ResourceUtils.isReadable(mockResource)).isFalse();
+
+		verify(mockResource, times(1)).isReadable();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test
+	public void isReadableWithNullResourceIsNullSafeReturnsFalse() {
+		assertThat(ResourceUtils.isReadable(null)).isFalse();
+	}
+
+	@Test
+	public void isWritableWithWritableResourceReturnsTrue() {
+
+		WritableResource mockResource = mock(WritableResource.class);
+
+		doReturn(true).when(mockResource).isWritable();
+
+		assertThat(ResourceUtils.isWritable(mockResource)).isTrue();
+
+		verify(mockResource, times(1)).isWritable();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test
+	public void isWritableWithNonWritableResourceReturnsFalse() {
+
+		WritableResource mockResource = mock(WritableResource.class);
+
+		doReturn(false).when(mockResource).isWritable();
+
+		assertThat(ResourceUtils.isWritable(mockResource)).isFalse();
+
+		verify(mockResource, times(1)).isWritable();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test
+	public void isWritableWithNonWritableResourceTypeReturnsFalse() {
+
+		Resource mockResource = mock(Resource.class);
+
+		assertThat(ResourceUtils.isWritable(mockResource)).isFalse();
+
+		verifyNoInteractions(mockResource);
+	}
+
+	@Test
+	public void isWritableWithNullResourceIsNullSafeReturnsFalse() {
+		assertThat(ResourceUtils.isWritable(null)).isFalse();
+	}
+
 	@Test
 	public void getWritableResourceReturnsWritableResourceFromResource() {