Create ConfigurationMetadataReader.java

microsphere-core-spring-boot-starter/src/main/java/io/microsphere/spring/boot/configuration/metadata/ConfigurationMetadataReader.java

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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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 io.microsphere.spring.boot.configuration.metadata;
+
+import io.microsphere.logging.Logger;
+import io.microsphere.logging.LoggerFactory;
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.core.io.support.ResourcePatternResolver;
+import org.springframework.lang.NonNull;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.util.HashSet;
+import java.util.Set;
+
+import static io.microsphere.text.FormatUtils.format;
+import static io.microsphere.util.ClassLoaderUtils.getDefaultClassLoader;
+import static io.microsphere.util.StringUtils.replace;
+import static org.springframework.core.io.support.ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX;
+
+/**
+ * The Reader of {@link ConfigurationMetadata}
+ *
+ * @author <a href="mailto:mercyblitz@gmail.com">Mercy<a/>
+ * @see ConfigurationMetadata
+ * @since 1.0.0
+ */
+public class ConfigurationMetadataReader {
+
+    private static final Logger logger = LoggerFactory.getLogger(ConfigurationMetadataReader.class);
+
+    private static final String METADATA_RESOURCE_NAME = "spring-configuration-metadata.json";
+
+    private static final String ADDITIONAL_METADATA_RESOURCE_NAME = "additional-spring-configuration-metadata.json";
+
+    private static final String META_INFO_PATH = "/META-INF/";
+
+    private static final String METADATA_RESOURCE_PATH = META_INFO_PATH + METADATA_RESOURCE_NAME;
+
+    private static final String ADDITIONAL_METADATA_RESOURCE_PATH = META_INFO_PATH + ADDITIONAL_METADATA_RESOURCE_NAME;
+
+    public static final String METADATA_RESOURCE_PATTERN_PATH = CLASSPATH_ALL_URL_PREFIX + METADATA_RESOURCE_PATH;
+
+    public static final String ADDITIONAL_METADATA_RESOURCE_PATTERN_PATH = CLASSPATH_ALL_URL_PREFIX + ADDITIONAL_METADATA_RESOURCE_PATH;
+
+    private final ResourcePatternResolver resourcePatternResolver;
+
+    public ConfigurationMetadataReader() {
+        this(getDefaultClassLoader());
+    }
+
+    public ConfigurationMetadataReader(ClassLoader classLoader) {
+        this.resourcePatternResolver = new PathMatchingResourcePatternResolver(classLoader);
+    }
+
+    public ConfigurationMetadata read() {
+        ConfigurationMetadata configurationMetadata = new ConfigurationMetadata();
+        Resource[] metadataResources = getMetadataResources();
+        int metadataResourcesSize = metadataResources.length;
+        Set<Resource> processedAdditionalMetadataResources = new HashSet<>(metadataResourcesSize);
+        for (int i = 0; i < metadataResourcesSize; i++) {
+            Resource resource = metadataResources[i];
+            processConfigurationMetadata(configurationMetadata, resource, processedAdditionalMetadataResources);
+        }
+        Resource[] additionalMetadataResources = getAdditionalMetadataResources();
+        for (Resource additionalMetadataResource : additionalMetadataResources) {
+            if (processedAdditionalMetadataResources.remove(additionalMetadataResource)) {
+                continue;
+            }
+            processConfigurationMetadata(configurationMetadata, additionalMetadataResource);
+        }
+        return configurationMetadata;
+    }
+
+    private void processConfigurationMetadata(ConfigurationMetadata configurationMetadata, Resource metadataResource,
+                                              Set<Resource> processedAdditionalMetadataResources) {
+        processConfigurationMetadata(configurationMetadata, metadataResource);
+        tryProcessAdditionalMetadataResource(configurationMetadata, metadataResource, processedAdditionalMetadataResources);
+    }
+
+    private void tryProcessAdditionalMetadataResource(ConfigurationMetadata configurationMetadata, Resource metadataResource,
+                                                      Set<Resource> processedAdditionalMetadataResources) {
+        try {
+            URI uri = metadataResource.getURI();
+            String metadataResourcePath = uri.toString();
+            String additionalMetadataResourcePath = replace(metadataResourcePath, METADATA_RESOURCE_NAME, ADDITIONAL_METADATA_RESOURCE_NAME);
+            Resource additionalMetadataResource = this.resourcePatternResolver.getResource(additionalMetadataResourcePath);
+            if (additionalMetadataResource.exists()) {
+                processConfigurationMetadata(configurationMetadata, additionalMetadataResource);
+                processedAdditionalMetadataResources.add(additionalMetadataResource);
+            } else {
+                if (logger.isDebugEnabled()) {
+                    logger.debug("The Additional Configuration Metadata resource[{}] can't be found", additionalMetadataResource);
+                }
+            }
+        } catch (IOException e) {
+            String message = format("The Additional Configuration Metadata resource[{}] can't be open", metadataResource);
+            throw new RuntimeException(message, e);
+        }
+    }
+
+    private void processConfigurationMetadata(ConfigurationMetadata configurationMetadata, Resource metadataResource) {
+        ConfigurationMetadata metadata = loadConfigurationMetadata(metadataResource);
+        configurationMetadata.merge(metadata);
+    }
+
+    private ConfigurationMetadata loadConfigurationMetadata(Resource metadataResource) {
+        JsonMarshaller jsonMarshaller = new JsonMarshaller();
+        final ConfigurationMetadata configurationMetadata;
+        try (InputStream inputStream = metadataResource.getInputStream()) {
+            configurationMetadata = jsonMarshaller.read(inputStream);
+            if (logger.isDebugEnabled()) {
+                logger.debug("Loaded the Configuration Metadata resource[{}] : {}", metadataResource, configurationMetadata);
+            }
+        } catch (Throwable e) {
+            String message = format("The Configuration Metadata resource[{}] can't be loaded", metadataResource);
+            throw new RuntimeException(message, e);
+        }
+        return configurationMetadata;
+    }
+
+    @NonNull
+    private Resource[] getMetadataResources() {
+        return getResources(METADATA_RESOURCE_PATTERN_PATH);
+    }
+
+    @NonNull
+    private Resource[] getAdditionalMetadataResources() {
+        return getResources(ADDITIONAL_METADATA_RESOURCE_PATTERN_PATH);
+    }
+
+    @NonNull
+    private Resource[] getResources(String metadataResourcePatternPath) {
+        Resource[] metadataResources = null;
+        try {
+            metadataResources = this.resourcePatternResolver.getResources(metadataResourcePatternPath);
+        } catch (IOException e) {
+            String message = format("The Configuration Metadata resources[pattern : {}] can't be read", metadataResourcePatternPath);
+            throw new RuntimeException(message, e);
+        }
+        return metadataResources;
+    }
+}