[ISSUES #8622] Add NacosEnvironment and add some unit tests (#8680)

* [ISSUES #8622] Add NacosEnvironment and add some unit tests

- remove magic number
- refactor all of them
- add some unit tests for env
- modify search rule and reformat
- fix search order
- fix p3c error

* fix ci error

* add some type converters

- enhance search method
- default_setting.properties is renamed nacos_default_setting.properties

* the property key of system environment replace dot with underscore

* add some default values and enhance SystemEnvPropertySource

* add the copyright information

client/src/main/java/com/alibaba/nacos/client/constant/Constants.java

@@ -35,6 +35,8 @@ public static class SysEnv {
 
         public static final String JM_SNAPSHOT_PATH = "JM.SNAPSHOT.PATH";
 
+        public static final String NACOS_ENVS_SEARCH = "nacos.envs.search";
+
     }
 
     public static class Disk {

client/src/main/java/com/alibaba/nacos/client/env/AbstractPropertySource.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 1999-2022 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      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 com.alibaba.nacos.client.env;
+
+abstract class AbstractPropertySource {
+
+    /**
+     * get property's type.
+     * @return name
+     */
+    abstract SourceType getType();
+
+    /**
+     * get property, if the value can not be got by the special key, the null will be returned.
+     * @param key special key
+     * @return value or null
+     */
+    abstract String getProperty(String key);
+
+}

client/src/main/java/com/alibaba/nacos/client/env/DefaultSettingPropertySource.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 1999-2022 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      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 com.alibaba.nacos.client.env;
+
+import com.alibaba.nacos.common.utils.ResourceUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Properties;
+
+class DefaultSettingPropertySource extends AbstractPropertySource {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultSettingPropertySource.class);
+
+    private static final String DEFAULT_SETTING_PATH = "classpath:nacos_default_setting.properties";
+
+    private final Properties defaultSetting = new Properties();
+
+    DefaultSettingPropertySource() {
+        try {
+            final URL resourceUrl = ResourceUtils.getResourceUrl(DEFAULT_SETTING_PATH);
+            final InputStream inputStream = resourceUrl.openStream();
+            defaultSetting.load(inputStream);
+        } catch (Exception e) {
+            LOGGER.warn("load default setting failed");
+        }
+    }
+
+    @Override
+    SourceType getType() {
+        return SourceType.DEFAULT_SETTING;
+    }
+
+    @Override
+    String getProperty(String key) {
+        return defaultSetting.getProperty(key);
+    }
+}

client/src/main/java/com/alibaba/nacos/client/env/JvmArgsPropertySource.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 1999-2022 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      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 com.alibaba.nacos.client.env;
+
+import java.util.Properties;
+
+class JvmArgsPropertySource extends AbstractPropertySource {
+
+    private final Properties properties;
+
+    JvmArgsPropertySource() {
+        this.properties = System.getProperties();
+    }
+
+    @Override
+    SourceType getType() {
+        return SourceType.JVM;
+    }
+
+    @Override
+    String getProperty(String key) {
+        return properties.getProperty(key);
+    }
+}

client/src/main/java/com/alibaba/nacos/client/env/NacosEnvironment.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 1999-2022 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      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 com.alibaba.nacos.client.env;
+
+/**
+ * nacos env interface.
+ *
+ * @author onewe
+ */
+public interface NacosEnvironment {
+
+    /**
+     * get property, if the value can not be got by the special key, the null will be returned.
+     *
+     * @param key special key
+     * @return string value or null.
+     */
+    String getProperty(String key);
+
+    /**
+     * get property, if the value can not be got by the special key, the default value will be returned.
+     * @param key special key
+     * @param defaultValue default value
+     * @return string value or default value.
+     */
+    String getProperty(String key, String defaultValue);
+
+    /**
+     * get boolean, if the value can not be got by the special key, the null will be returned.
+     *
+     * @param key special key
+     * @return boolean value or null.
+     */
+    Boolean getBoolean(String key);
+
+    /**
+     * get boolean, if the value can not be got by the special key, the default value will be returned.
+     * @param key special key
+     * @param defaultValue default value
+     * @return boolean value or defaultValue.
+     */
+    Boolean getBoolean(String key, Boolean defaultValue);
+
+    /**
+     * get integer, if the value can not be got by the special key, the null will be returned.
+     *
+     * @param key special key
+     * @return integer value or null
+     */
+    Integer getInteger(String key);
+
+    /**
+     * get integer, if the value can not be got by the special key, the default value will be returned.
+     * @param key special key
+     * @param defaultValue default value
+     * @return integer value or default value
+     */
+    Integer getInteger(String key, Integer defaultValue);
+
+    /**
+     * get long, if the value can not be got by the special key, the null will be returned.
+     *
+     * @param key special key
+     * @return long value or null
+     */
+    Long getLong(String key);
+
+    /**
+     * get long, if the value can not be got by the special key, the default value will be returned.
+     * @param key special key
+     * @param defaultValue default value
+     * @return long value or default value
+     */
+    Long getLong(String key, Long defaultValue);
+
+}

client/src/main/java/com/alibaba/nacos/client/env/NacosEnvironmentFactory.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 1999-2022 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      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 com.alibaba.nacos.client.env;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.Properties;
+
+class NacosEnvironmentFactory {
+
+    /**
+     * create nacos environment.
+     * @return NacosEnvironment's proxy object, it contains a SearchableEnvironment object.
+     * @see SearchableEnvironment
+     */
+    static NacosEnvironment createEnvironment() {
+
+        return (NacosEnvironment) Proxy.newProxyInstance(NacosEnvironmentFactory.class.getClassLoader(), new Class[] {NacosEnvironment.class},
+                new NacosEnvironmentDelegate() {
+                    volatile NacosEnvironment environment;
+
+                    @Override
+                    public void init(Properties properties) {
+                        if (environment == null) {
+                            synchronized (NacosEnvironmentFactory.class) {
+                                if (environment == null) {
+                                    environment = new SearchableEnvironment(properties);
+                                }
+                            }
+                        }
+                    }
+
+                    @Override
+                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+                        if (environment == null) {
+                            throw new IllegalStateException(
+                                    "Nacos environment doesn't init, please call NacosEnvs#init method then try it again.");
+                        }
+                        return method.invoke(environment, args);
+                    }
+                });
+    }
+
+    interface NacosEnvironmentDelegate extends InvocationHandler {
+
+        /**
+         * init environment.
+         * @param properties user customize properties
+         */
+        void init(Properties properties);
+    }
+
+}