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Configuration Core module.
/*
* Copyright (c) 2020 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;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import io.helidon.config.spi.ConfigNode;
import io.helidon.config.spi.ConfigNode.ListNode;
import io.helidon.config.spi.ConfigNode.ObjectNode;
import io.helidon.config.spi.ConfigNode.ValueNode;
/**
* Common implementation of {@link ListNode.Builder} and {@link ObjectNode.Builder}.
*
* @param type of id
* @param type of builder implementation
*/
public abstract class AbstractNodeBuilderImpl {
private final B thisBuilder;
private Function tokenResolver;
@SuppressWarnings("unchecked")
AbstractNodeBuilderImpl(Function tokenResolver) {
this.tokenResolver = tokenResolver;
thisBuilder = (B) this;
}
/**
* Wraps node into mergeable one.
*
* @param node original node
* @return new instance of mergeable node or original node if already was mergeable.
*/
static MergeableNode wrap(ConfigNode node) {
return wrap(node, Function.identity());
}
/**
* Wraps node into mergeable one.
*
* @param node original node
* @param resolveTokenFunction a token resolver
* @return new instance of mergeable node or original node if already was mergeable.
*/
static MergeableNode wrap(ConfigNode node, Function resolveTokenFunction) {
switch (node.nodeType()) {
case OBJECT:
return ObjectNodeImpl.wrap((ObjectNode) node, resolveTokenFunction);
case LIST:
return ListNodeImpl.wrap((ListNode) node, resolveTokenFunction);
case VALUE:
return ValueNodeImpl.wrap((ValueNode) node);
default:
throw new IllegalArgumentException("Unsupported node type: " + node.getClass().getName());
}
}
static String formatFrom(String from) {
if (from != null) {
return " from " + from;
} else {
return "";
}
}
/**
* Human readable description of current builder implementation to be used in logs and exception messages.
*
* @return builder description
*/
protected abstract String typeDescription();
/**
* Returns id computed from key.
*
* @param key key to be used to extract id from
* @return id computed from key
*/
protected abstract ID id(MergingKey key);
/**
* Returns member instance associated with specified id.
*
* @param id member id
* @return member instance associated with specified id.
*/
protected abstract MergeableNode member(ID id);
/**
* Updates/replaces a member of specified id by specified node.
*
* @param id member id
* @param node new node
*/
protected abstract void update(ID id, MergeableNode node);
/**
* Merges a member of specified id with specified node.
*
* @param id member id
* @param node new node
*/
protected abstract void merge(ID id, MergeableNode node);
/**
* Applies deep merging through whole structure.
*
* @param key key of node
* @param node node to be merged into
* @return modified builder
*/
protected B deepMerge(MergingKey key, MergeableNode node) {
// compotes id from current key
ID id = id(key);
if (key.isLeaf()) {
// merges leaf nodes
merge(id, node);
} else {
// get current member associated with id
MergeableNode member = member(id);
// merges current member with specified node
switch (member.nodeType()) {
case OBJECT:
mergeObjectMember((ObjectNode) member, key, node, id);
break;
case LIST:
mergeListMember((ListNode) member, key, node, id);
break;
case VALUE:
mergeValueMember((ValueNode) member, key, node, id);
break;
default:
throw new IllegalArgumentException("Unsupported node type: " + member.getClass().getName());
}
}
return thisBuilder;
}
private void mergeValueMember(ValueNode member, MergingKey key, MergeableNode node, ID id) {
ObjectNode on = ObjectNodeBuilderImpl.create(Map.of(), tokenResolver).value(member.value()).build();
ConfigNode merged = ObjectNodeBuilderImpl
.create(on, tokenResolver) // make copy of member
.value(on.value())
.deepMerge(key.rest(), node) // merge it with specified node
.build();
update(id, wrap(merged, tokenResolver));
}
private void mergeListMember(ListNode member, MergingKey key, MergeableNode node, ID id) {
try {
// deep merge of list with specified node
ConfigNode merged = ListNodeBuilderImpl.from(member, tokenResolver) // make copy of member
.value(member.value())
.deepMerge(key.rest(), node) // merge it with specified node
.build();
// updates/replaces original member associated by id with new merged value
update(id, wrap(merged, tokenResolver));
} catch (ConfigException ex) {
throw new ConfigException(id + ": " + ex.getLocalizedMessage(), ex);
}
}
private void mergeObjectMember(ObjectNode member, MergingKey key, MergeableNode node, ID id) {
try {
// deep merge of object with specified node
ConfigNode merged = ObjectNodeBuilderImpl
.create(member, tokenResolver) // make copy of member
.value(member.value())
.deepMerge(key.rest(), node) // merge it with specified node
.build();
// updates/replaces original member associated by id with new merged value
update(id, wrap(merged, tokenResolver));
} catch (ConfigException ex) {
throw new ConfigException(id + ": " + ex.getLocalizedMessage(), ex);
}
}
Function tokenResolver() {
return tokenResolver;
}
/**
* Internal config node key useful during internal structure building.
*/
public static class MergingKey {
private final String first;
private final MergingKey rest;
private MergingKey(String first, MergingKey rest) {
Objects.requireNonNull(first, "first cannot be null");
this.first = first;
this.rest = rest;
}
/**
* Creates instance of Key parsed from string representation.
*
* @param key fully-qualified key
* @return new instance of Key
*/
public static MergingKey of(String key) {
Objects.requireNonNull(key, "key cannot be null");
int index = key.indexOf('.');
if (index == -1) {
return new MergingKey(key, null);
} else {
return new MergingKey(key.substring(0, index), MergingKey.of(key.substring(index + 1)));
}
}
/**
* Returns first key token.
*
* @return first key token.
*/
public String first() {
return first;
}
/**
* Returns a sub-key of the key. If the key represents a leaf node it returns {@code null}.
*
* @return a sub-key of the key.
*/
public MergingKey rest() {
return rest;
}
/**
* Returns {@code true} in case the key represents a leaf node.
*
* @return {@code true} in case the key represents a leaf node.
*/
public boolean isLeaf() {
return (rest == null);
}
@Override
public String toString() {
return first + (rest != null ? "." + rest : "");
}
}
}