Add abstract base class supporting the development of Spring Data Repository, Apache Geode CacheLoader/CacheWriter implementations.

spring-geode/src/main/java/org/springframework/geode/cache/support/RepositoryCacheLoaderWriterSupport.java

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+/*
+ * Copyright 2019 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.cache.support;
+
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import org.apache.geode.cache.CacheLoader;
+import org.apache.geode.cache.CacheLoaderException;
+import org.apache.geode.cache.CacheRuntimeException;
+import org.apache.geode.cache.CacheWriter;
+import org.apache.geode.cache.LoaderHelper;
+import org.springframework.context.EnvironmentAware;
+import org.springframework.core.env.Environment;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.repository.Repository;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * Abstract base class supporting the implementation of Apache Geode / Pivotal GemFire {@link CacheLoader CacheLoaders}
+ * and {@link CacheWriter CacheWriters} backed by Spring Data {@link Repository Repositories}.
+ *
+ * @author John Blum
+ * @see org.apache.geode.cache.CacheLoader
+ * @see org.apache.geode.cache.CacheWriter
+ * @see org.springframework.context.EnvironmentAware
+ * @see org.springframework.core.env.Environment
+ * @see org.springframework.data.repository.CrudRepository
+ * @see org.springframework.data.repository.Repository
+ * @see org.springframework.geode.cache.support.CacheLoaderSupport
+ * @since 1.1.0
+ */
+public abstract class RepositoryCacheLoaderWriterSupport<T, ID>
+		implements CacheLoaderSupport<ID, T>, CacheWriterSupport<ID, T>, EnvironmentAware {
+
+	public static final String NUKE_AND_PAVE_PROPERTY = "spring.boot.data.gemfire.data.source.nuke-and-pave";
+
+	protected static final String DATA_ACCESS_ERROR =
+		"Exception occurred while accessing entity [%s] in external data source";
+
+	private final CrudRepository<T, ID> repository;
+
+	private Environment environment;
+
+	protected RepositoryCacheLoaderWriterSupport(CrudRepository<T, ID> repository) {
+
+		Assert.notNull(repository, "Repository is required");
+
+		this.repository = repository;
+	}
+
+	protected boolean isNukeAndPaveEnabled() {
+
+		return getEnvironment()
+			.map(env -> env.getProperty(NUKE_AND_PAVE_PROPERTY, Boolean.class))
+			.orElse(Boolean.getBoolean(NUKE_AND_PAVE_PROPERTY));
+	}
+
+	@Override @SuppressWarnings("all")
+	public void setEnvironment(@Nullable Environment environment) {
+		this.environment = environment;
+	}
+
+	protected Optional<Environment> getEnvironment() {
+		return Optional.ofNullable(this.environment);
+	}
+
+	protected @NonNull CrudRepository<T, ID> getRepository() {
+		return this.repository;
+	}
+
+	@SuppressWarnings("all")
+	protected <S, R> R doRepositoryOp(S entity, Function<S, R> repositoryOperation) {
+
+		try {
+			return repositoryOperation.apply(entity);
+		}
+		catch (Throwable cause) {
+			throw newCacheRuntimeException(() -> String.format(DATA_ACCESS_ERROR, entity), cause);
+		}
+	}
+
+	@Override
+	public T load(LoaderHelper<ID, T> helper) throws CacheLoaderException {
+		return null;
+	}
+
+	protected abstract CacheRuntimeException newCacheRuntimeException(
+		Supplier<String> messageSupplier, Throwable cause);
+
+	@SuppressWarnings("unchecked")
+	public <U extends RepositoryCacheLoaderWriterSupport<T, ID>> U with(Environment environment) {
+
+		setEnvironment(environment);
+
+		return (U) this;
+	}
+}