com.virtlink.commons.configuration2.jackson.JacksonConfiguration Maven / Gradle / Ivy
/*
* Copyright 2015-2023 - Daniel A. A. Pelsmaeker
*
* 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.virtlink.commons.configuration2.jackson;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import org.apache.commons.configuration2.BaseHierarchicalConfiguration;
import org.apache.commons.configuration2.FileBasedConfiguration;
import org.apache.commons.configuration2.HierarchicalConfiguration;
import org.apache.commons.configuration2.ex.ConfigurationException;
import org.apache.commons.configuration2.io.FileLocator;
import org.apache.commons.configuration2.io.FileLocatorAware;
import org.apache.commons.configuration2.io.InputStreamSupport;
import org.apache.commons.configuration2.tree.ImmutableNode;
import org.apache.commons.configuration2.tree.ImmutableNode.Builder;
import javax.annotation.Nullable;
import java.io.*;
import java.util.*;
/**
* A configuration using a Jackson language (e.g. YAML, JSON).
*/
@SuppressWarnings("RedundantThrows")
public abstract class JacksonConfiguration extends BaseHierarchicalConfiguration implements FileBasedConfiguration, InputStreamSupport, FileLocatorAware {
private static final TypeReference> HASH_MAP_TYPE_REFERENCE
= new TypeReference>() {};
private final SimpleModule module;
private final ObjectMapper mapper;
/**
* The {@link FileLocator} that may specify where the source/destination file is.
*
* This is for use by derived classses, if necessary.
*/
@Nullable
protected FileLocator locator = null;
/**
* Initializes a new instance of the {@link JacksonConfiguration} class.
*
* @param factory the Jackson factory to use
*/
protected JacksonConfiguration(final JsonFactory factory) {
this(factory, null);
}
/**
* Initializes a new instance of the {@link JacksonConfiguration} class.
*
* @param factory the Jackson factory to use
* @param config the configuration whose nodes to copy into this configuration
*/
protected JacksonConfiguration(final JsonFactory factory, final HierarchicalConfiguration config) {
super(config);
Preconditions.checkNotNull(factory);
this.module = new SimpleModule();
this.mapper = new ObjectMapper(factory);
this.mapper.registerModule(this.module);
}
/**
* Reads the configuration.
*
* @param inputStream the input stream to read from
* @throws IOException if an I/O error occurs
* @throws ConfigurationException if a non-I/O related problem occurs
*/
@Override
public void read(final InputStream inputStream) throws ConfigurationException, IOException {
try (Reader reader = new InputStreamReader(inputStream)) {
read(reader);
}
}
/**
* Reads the configuration.
*
* @param reader the reader to read from
* @throws IOException if an I/O error occurs
* @throws ConfigurationException if a non-I/O related problem occurs
*/
@Override
public void read(final Reader reader) throws ConfigurationException, IOException {
Preconditions.checkNotNull(reader);
final HashMap settings = this.mapper.readValue(reader, HASH_MAP_TYPE_REFERENCE);
final ImmutableNode rootNode = toNode(new Builder(), settings);
this.getSubConfigurationParentModel().mergeRoot(rootNode, null, null, null, this);
}
/**
* Writes the configuration.
*
* @param writer the writer to write to
* @throws IOException if an I/O error occurs
* @throws ConfigurationException if a non-I/O related problem occurs
*/
@Override
public void write(final Writer writer) throws ConfigurationException, IOException {
Preconditions.checkNotNull(writer);
@SuppressWarnings("unchecked")
final HashMap settings = (HashMap) fromNode(this.getModel().getInMemoryRepresentation());
this.mapper.writerWithDefaultPrettyPrinter().writeValue(writer, settings);
}
/**
* Sets the file locator to use for the next invocation of {@link #read(InputStream)} or {@link #write(Writer)}.
*
* @param locator the file locator to use; or {@code null}
*/
@Override
public void initFileLocator(@Nullable final FileLocator locator) {
this.locator = locator;
}
/**
* Creates a node for the specified object.
*
* @param builder the node builder
* @param obj the object
* @return the created node
*/
private ImmutableNode toNode(final Builder builder, final Object obj) {
assert !(obj instanceof List);
if (obj instanceof Map) {
@SuppressWarnings("unchecked")
final Map map = (Map) obj;
return mapToNode(builder, map);
} else {
return valueToNode(builder, obj);
}
}
/**
* Creates a node for the specified map.
*
* @param builder the node builder
* @param map the map
* @return the created node
*/
private ImmutableNode mapToNode(final Builder builder, final Map map) {
for (final Map.Entry entry : map.entrySet()) {
final String key = entry.getKey();
final Object value = entry.getValue();
if (value instanceof List) {
// For a list, add each list item as a child of this node.
for (final Object item : (List)value) {
addChildNode(builder, key, item);
}
} else {
// Otherwise, add the value as a child of this node.
addChildNode(builder, key, value);
}
}
return builder.create();
}
/**
* Adds a child node to the specified builder.
*
* @param builder the builder to add the node to
* @param name the name of the node
* @param value the value of the node
*/
private void addChildNode(final Builder builder, final String name, final Object value) {
assert !(value instanceof List);
final Builder childBuilder = new Builder();
// Set the name of the child node.
childBuilder.name(name);
// Set the value of the child node.
final ImmutableNode childNode = toNode(childBuilder, value);
// Add the node to the children of the node being built.
builder.addChild(childNode);
}
/**
* Creates a node for the specified value.
*
* @param builder the node builder
* @param value the value
* @return the created node
*/
private ImmutableNode valueToNode(final Builder builder, final Object value) {
// Set the value of the node being built.
return builder.value(value).create();
}
/**
* Gets a serialization object from a node.
*
* @param node the node
* @return the object representing the node
*/
private Object fromNode(final ImmutableNode node) {
if (!node.getChildren().isEmpty()) {
final Map> children = getChildrenWithName(node);
final HashMap map = new HashMap<>();
for (final Map.Entry> entry : children.entrySet()) {
assert !entry.getValue().isEmpty();
if (entry.getValue().size() == 1) {
// Just one node.
final ImmutableNode child = entry.getValue().get(0);
final Object childValue = fromNode(child);
map.put(entry.getKey(), childValue);
} else {
// Multiple nodes.
final ArrayList