| /* |
| * 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 org.apache.nifi.registry; |
| |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Provides a registry of variables available for use by various components and |
| * extension points. This enables components to reference variable names rather |
| * than explicit values which can make configurations of those components more |
| * portable. |
| */ |
| public interface VariableRegistry { |
| |
| /** |
| * Returns an empty registry which can be used as a more intentional null |
| * value. |
| */ |
| public static final VariableRegistry EMPTY_REGISTRY = () -> Collections.emptyMap(); |
| |
| /** |
| * Provides a registry containing all environment variables and system |
| * properties. System properties receive precedence. |
| */ |
| public static final VariableRegistry ENVIRONMENT_SYSTEM_REGISTRY = new VariableRegistry() { |
| final Map<VariableDescriptor, String> map = new HashMap<>(); |
| |
| { |
| System.getenv().entrySet().stream().forEach((entry) -> { |
| final VariableDescriptor desc = new VariableDescriptor.Builder(entry.getKey()) |
| .description("Env Var") |
| .sensitive(false) |
| .build(); |
| map.put(desc, entry.getValue()); |
| }); |
| System.getProperties().entrySet().stream().forEach((entry) -> { |
| final VariableDescriptor desc = new VariableDescriptor.Builder(entry.getKey().toString()) |
| .description("System Property") |
| .sensitive(false) |
| .build(); |
| map.put(desc, entry.getValue().toString()); |
| }); |
| } |
| |
| @Override |
| public Map<VariableDescriptor, String> getVariableMap() { |
| return Collections.unmodifiableMap(map); |
| |
| } |
| |
| }; |
| |
| /** |
| * Provides access to a map of variable key/value pairs. For variables |
| * considered to be sensitive care must be taken to ensure their values are |
| * protected whenever stored or exposed. |
| * |
| * @return An immutable map of all variables in the registry |
| */ |
| |
| Map<VariableDescriptor, String> getVariableMap(); |
| |
| /** |
| * Returns the VariableDescriptor for the given key name if it exists. |
| * |
| * @param name the string name of the VariableDescriptor to lookup. |
| * @return the variable descriptor registered for this name if it exists; |
| * null otherwise |
| */ |
| default VariableDescriptor getVariableKey(final String name) { |
| if (name == null) { |
| return null; |
| } |
| final VariableDescriptor spec = new VariableDescriptor(name); |
| for (final Map.Entry<VariableDescriptor, String> entry : getVariableMap().entrySet()) { |
| if (entry.getKey().equals(spec)) { |
| return entry.getKey(); |
| } |
| } |
| return null; |
| |
| } |
| |
| /** |
| * Gets the variable value |
| * |
| * @param name the string name of the VariableDescriptor that is the key of |
| * the value to lookup. |
| * @return the value associated with the given variable name if found; null |
| * otherwise |
| */ |
| default String getVariableValue(final String name) { |
| if (name == null) { |
| return null; |
| } |
| return getVariableMap().get(new VariableDescriptor(name)); |
| } |
| |
| /** |
| * Gets the variable value |
| * |
| * @param descriptor the descriptor for which to lookup the variable value. |
| * @return the variable value if the given descriptor is equivalent to one |
| * of the entries in the registry; null otherwise |
| */ |
| default String getVariableValue(final VariableDescriptor descriptor) { |
| if (descriptor == null) { |
| return null; |
| } |
| return getVariableMap().get(descriptor); |
| } |
| |
| } |