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/*
* Copyright (c) 2017, 2021 Oracle and/or its affiliates.
*
* 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 io.helidon.config.spi;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import io.helidon.config.ListNodeBuilderImpl;
import io.helidon.config.ObjectNodeBuilderImpl;
import io.helidon.config.ValueNodeImpl;
/**
* Marker interface identifying a config node implementation.
*/
public interface ConfigNode {
/**
* Get the type of this node.
*
* @return NodeType this node represents
*/
NodeType nodeType();
/**
* Get the direct value of this config node. Any node type can have a direct value.
*
* @return a value if present, {@code empty} otherwise
*/
Optional value();
/**
* Base types of config nodes.
*/
enum NodeType {
/**
* An object (complex structure), optionally may have a value.
*/
OBJECT,
/**
* A list of values, optionally may have a value.
*/
LIST,
/**
* Only has value.
*/
VALUE
}
/**
* Single string-based configuration value.
*
* NOTE: Do not implement this interface yourself but rather use {@link #create(String)}.
*/
interface ValueNode extends ConfigNode {
@Override
default NodeType nodeType() {
return NodeType.VALUE;
}
/**
* Get the value of this value node.
* @return string with the node value
*/
String get();
/**
* Create new instance of the {@link ValueNode} from specified String {@code value}.
*
* @param value string value
* @return new instance of the {@link ValueNode}
*/
static ValueNode create(String value) {
return ValueNodeImpl.create(value);
}
}
/**
* ConfigNode-based list of configuration values.
*
* List contains instance of {@link ValueNode}, {@link ListNode} as well as {@link ObjectNode}.
*
* NOTE: Do not implement this interface yourself but rather use {@link #builder()}.
*/
interface ListNode extends ConfigNode, List {
@Override
default NodeType nodeType() {
return NodeType.LIST;
}
/**
* Creates new instance of {@link Builder}.
*
* @return new instance of {@link Builder}.
*/
static Builder builder() {
return new ListNodeBuilderImpl();
}
/**
* Builder to build {@link ListNode} instance.
*/
interface Builder extends io.helidon.common.Builder {
/**
* Adds String value to the list.
*
* @param value string value
* @return modified builder
*/
default Builder addValue(String value) {
return addValue(ValueNode.create(value));
}
/**
* Adds String value to the list.
*
* @param value string value
* @return modified builder
*/
Builder addValue(ValueNode value);
/**
* Adds Object node to the list.
*
* @param object object node
* @return modified builder
*/
Builder addObject(ObjectNode object);
/**
* Adds List node to the list.
*
* @param list list node
* @return modified builder
*/
Builder addList(ListNode list);
/**
* Sets the node value associated with the current node.
*
* @param value value to be assigned
* @return modified builder
*/
Builder value(String value);
}
}
/**
* Configuration node representing a hierarchical structure parsed by a
* suitable {@link ConfigParser} if necessary.
*
* In the map exposed by this interface, the map keys are {@code String}s
* containing the fully-qualified dotted names of the config keys and the
* map values are the corresponding {@link ValueNode} or {@link ListNode}
* instances. The map never contains {@link ObjectNode} values because the
* {@link ObjectNode} is implemented as a flat map.
*
* NOTE: Do not implement this interface yourself but rather use
* {@link #builder()}.
*/
interface ObjectNode extends ConfigNode, Map {
@Override
default NodeType nodeType() {
return NodeType.OBJECT;
}
/**
* Returns empty object node.
*
* @return empty object node.
*/
static ObjectNode empty() {
return SpiHelper.EmptyObjectNodeHolder.EMPTY;
}
/**
* Returns an object node containing a single simple value.
*
* @param key key of the value
* @param value value
* @return a new object node
*/
static ObjectNode simple(String key, String value) {
return ObjectNode.builder()
.addValue(key, value)
.build();
}
/**
* Creates new instance of {@link Builder}.
*
* @return new instance of {@link Builder}.
*/
static Builder builder() {
return ObjectNodeBuilderImpl.create();
}
/**
* Builder to build {@link ObjectNode} instance.
*/
interface Builder {
/**
* Sets String value associated with specified {@code key}.
*
* @param key member key
* @param value string value
* @return modified builder
*/
default Builder addValue(String key, String value) {
return addValue(key, ValueNode.create(value));
}
/**
* Sets String value associated with specified {@code key}.
*
* @param key member key
* @param value string value
* @return modified builder
*/
Builder addValue(String key, ValueNode value);
/**
* Sets Object node associated with specified {@code key}.
*
* @param key member key
* @param object object node
* @return modified builder
*/
Builder addObject(String key, ObjectNode object);
/**
* Sets List node associated with specified {@code key}.
*
* @param key member key
* @param list list node
* @return modified builder
*/
Builder addList(String key, ListNode list);
/**
* Sets the node value associated with the current node.
*
* @param value value to be assigned
* @return modified builder
*/
Builder value(String value);
/**
* Build new instance of {@link ObjectNode}.
*
* @return new instance of {@link ObjectNode}.
*/
ObjectNode build();
/**
* Add a config node.
* The method will determine the type of the node and add it to builder.
*
* @param key key of the node
* @param node node to be added
* @return modified builder
*/
Builder addNode(String key, ConfigNode node);
}
}
}