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/*
* Copyright 2021 obvj.net
*
* 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 net.obvj.confectory;
import java.util.*;
import java.util.function.Function;
import java.util.stream.Stream;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import net.obvj.confectory.settings.ConfectorySettings;
/**
* An object that holds multiple {@code Configuration} objects and retrieves configuration
* data seamlessly, by namespace and key.
*
* The {@code Configuration} objects are sorted by precedence (from highest to lowest).
* So, in case of key collision, the object with the highest precedence will be selected
* first. The container may still select other lower-precedence {@code Configuration}
* objects if a key is not found in the highest-precedence {@code Configuration}.
*
* To create a new empty container, use the default constructor
* {@code new ConfigurationContainer()}. To create a new container with preset
* {@code Configuration} objects, pass them as "var-args".
*
* Use the {@code add(Configuration)} method at any time to register new objects inside
* the container.
*
* To retrieve {@code Configuration} data, use any of the getter methods, specifying a
* namespace and key.
*
* Single-argument getter methods can be used to retrieve data from {@code Configuration}
* objects that do not have a declared namespace. These methods may also retrieve data
* from all {@code Configuration} objects if the selected data-fetch strategy is
* {@code LENIENT}.
*
* Each container may have a custom {@link DataFetchStrategy} which may be specified at
* container construction time and modified using the setter method anytime. If not
* specified, the container uses the default choice configured via
* {@link ConfectorySettings}.
*
* IMPORTANT: This class works only with map-based {@code Configuration}
* objects (e.g.: {@code Properties}, {@code JSONObject}, {@code JsonNode}, etc.). In
* other words, only "container" objects which values can be accessed using either a key
* or path expression (e.g. {@code JSONPath}). POJO-based {@code Configuration} objects
* are not supported inside a the {@link ConfigurationContainer}.
*
* @author oswaldo.bapvic.jr (Oswaldo Junior)
* @since 0.1.0
*
* @see Configuration
* @see DataFetchStrategy
*/
public class ConfigurationContainer
{
protected static final String DEFAULT_NAMESPACE = "";
private Map>> configMap = new HashMap<>();
private DataFetchStrategy dataFetchStrategy;
/**
* Builds a new {@code ConfigurationContainer} with an arbitrary number of preset
* {@code Configuration} objects to be registered.
*
* @param configs an arbitrary number of {@code Configuration} objects (zero or more) to
* be registered at constructor time
*/
public ConfigurationContainer(Configuration... configs)
{
this(null, configs);
}
/**
* Builds a new {@code ConfigurationContainer} with a custom {@link DataFetchStrategy} and
* an arbitrary number of preset {@code Configuration} objects.
*
* @param dataFetchStrategy an optional {@link DataFetchStrategy} to be applied by this
* container; {@code null} is allowed and means the default
* strategy will be applied
* @param configs an arbitrary number of {@code Configuration} objects (zero or
* more) to be registered at constructor time
*/
public ConfigurationContainer(DataFetchStrategy dataFetchStrategy, Configuration... configs)
{
ConfectorySettings settings = Confectory.settings();
setDataFetchStrategy(ObjectUtils.defaultIfNull(dataFetchStrategy, settings.getDefaultDataFetchStrategy()));
Arrays.stream(configs).forEach(this::add);
}
/**
* Returns the {@code DataFetchStrategy} associated with this container.
*
* @return a {@link DataFetchStrategy}
*/
public DataFetchStrategy getDataFetchStrategy()
{
return dataFetchStrategy;
}
/**
* Defines a custom {@code DataFetchStrategy} for this container.
*
* @param strategy the {@link DataFetchStrategy} to set; not null
* @throws NullPointerException if the specified {@code strategy} is null
*/
public void setDataFetchStrategy(DataFetchStrategy strategy)
{
dataFetchStrategy = Objects.requireNonNull(strategy, "the DataFetchStrategy must not be null");
}
/**
* Adds the specified {@code Configuration} to this container.
*
* @param configuration the {@link Configuration} to be added to the container
*/
public void add(Configuration configuration)
{
String namespace = parseNamespace(configuration.getNamespace());
Set> configSet = configMap.computeIfAbsent(namespace, k -> new HashSet<>());
configSet.add(configuration);
}
/**
* Copies all of the {@code Configuration} objects from another container to this
* container.
*
* @param source the source container which {@code Configuration} objects are to be stored
* in this container; {@code null} is allowed
*/
public void addAll(ConfigurationContainer source)
{
if (source != null)
{
source.configMap.values().stream().flatMap(Collection::stream).forEach(this::add);
}
}
/**
* Removes all of the {@code Configuration} objects from this container.
*/
public void clear()
{
configMap.clear();
}
/**
* Returns the {@code Boolean} object associated with the specified {@code key} in the
* default namespace (or in all namespaces depending on the {@link DataFetchStrategy} in
* scope).
*
* @param key the object key (or path)
* @return the {@code Boolean} object associated with the specified {@code key};
* {@code null} if not found
*
* @see DataFetchStrategy
*/
public Boolean getBoolean(String key)
{
return getBoolean(DEFAULT_NAMESPACE, key);
}
/**
* Returns the {@code Boolean} object associated with the specified {@code key} in the
* specified {@code namespace}.
*
* @param namespace the namespace to be used
* @param key the object key (or path)
* @return the {@code Boolean} object associated with the specified {@code key};
* {@code null} if not found
*/
public Boolean getBoolean(String namespace, String key)
{
return getValue(namespace, config -> config.getBoolean(key));
}
/**
* Returns the {@code Integer} object associated with the specified {@code key} in the
* default namespace (or in all namespaces depending on the {@link DataFetchStrategy} in
* scope).
*
* @param key the object key (or path)
* @return the {@code Integer} object associated with the specified {@code key};
* {@code null} if not found
*
* @see DataFetchStrategy
*/
public Integer getInteger(String key)
{
return getInteger(DEFAULT_NAMESPACE, key);
}
/**
* Returns the {@code Integer} object associated with the specified {@code key} in the
* specified {@code namespace}.
*
* @param namespace the namespace to be used
* @param key the object key (or path)
* @return the {@code Integer} object associated with the specified {@code key};
* {@code null} if not found
*/
public Integer getInteger(String namespace, String key)
{
return getValue(namespace, config -> config.getInteger(key));
}
/**
* Returns the {@code Long} object associated with the specified {@code key} in the
* default namespace (or in all namespaces depending on the {@link DataFetchStrategy} in
* scope).
*
* @param key the object key (or path)
* @return the {@code Long} object associated with the specified {@code key}; {@code null}
* if not found
*
* @see DataFetchStrategy
*/
public Long getLong(String key)
{
return getLong(DEFAULT_NAMESPACE, key);
}
/**
* Returns the {@code Long} object associated with the specified {@code key} in the
* specified {@code namespace}.
*
* @param namespace the namespace to be used
* @param key the object key (or path)
* @return the {@code Long} object associated with the specified {@code key}; {@code null}
* if not found
*/
public Long getLong(String namespace, String key)
{
return getValue(namespace, config -> config.getLong(key));
}
/**
* Returns the {@code Double} object associated with the specified {@code key} in the
* default namespace (or in all namespaces depending on the {@link DataFetchStrategy} in
* scope).
*
* @param key the object key (or path)
* @return the {@code Double} value associated with the specified {@code key};
* {@code null} if not found
*
* @see DataFetchStrategy
*/
public Double getDouble(String key)
{
return getDouble(DEFAULT_NAMESPACE, key);
}
/**
* Returns the {@code Double} object associated with the specified {@code key} in the
* specified {@code namespace}.
*
* @param namespace the namespace to be used
* @param key the object key (or path)
* @return the {@code Double} object associated with the specified {@code key};
* {@code null} if not found
*/
public Double getDouble(String namespace, String key)
{
return getValue(namespace, config -> config.getDouble(key));
}
/**
* Returns the {@code String} object associated with the specified {@code key} in the
* default namespace (or in all namespaces depending on the {@link DataFetchStrategy} in
* scope).
*
* @param key the object key (or path)
* @return the {@code String} object associated with the specified {@code key};
* {@code null} if not found
*
* @see DataFetchStrategy
*/
public String getString(String key)
{
return getString(DEFAULT_NAMESPACE, key);
}
/**
* Returns the {@code String} object associated with the specified {@code key} in the
* specified {@code namespace}.
*
* @param namespace the namespace to be used
* @param key the object key (or path)
* @return the {@code String} object associated with the specified {@code key};
* {@code null} if not found
*/
public String getString(String namespace, String key)
{
return getValue(namespace, config -> config.getString(key));
}
/**
* Template method for retrieving properties from the {@code configMap}.
*
* @param the value return type
* @param namespace the namespace which property is to be fetched
* @param mainFunction the main data fetch function; applies a particular method to the
* {@code Configuration} objects in process
*
* @return the value evaluated by the {@code mainFunction}, or {@code null} if not found
*/
protected T getValue(String namespace, Function, T> mainFunction)
{
Iterator> iterator = getConfigurationStream(namespace).iterator();
while (iterator.hasNext())
{
Configuration config = iterator.next();
T value = mainFunction.apply(config);
if (value != null)
{
return value;
}
}
return null;
}
/**
* Retrieves a stream of {@link Configuration} objects on a given namespace.
*
* @param namespace the namespace to be searched
* @return a stream of {@link Configuration} objects or an empty stream, never
* {@code null}
*/
private Stream> getConfigurationStream(String namespace)
{
return dataFetchStrategy.getConfigurationStream(namespace, configMap);
}
/**
* Returns either the passed namespace, or the value defined for
* {@code DEFAULT_NAMESPACE}, if the passed argument is empty or null
*
* @param namespace the namespace to the checked
* @return the passed namespace, or the value of {@code DEFAULT_NAMESPACE}, never
* {@code null}
*/
private String parseNamespace(String namespace)
{
return StringUtils.defaultString(namespace, DEFAULT_NAMESPACE);
}
/**
* Returns the number of {@code Configuration} objects in this container.
*
* @return the number of {@code Configuration} objects in this container
* @since 1.0.0
*/
public long size()
{
return configMap.values().stream().mapToInt(Set::size).sum();
}
/**
* Returns the number of {@code Configuration} objects associated with the specified
* {@code namespace} in this container.
*
* @param namespace the namespace to be tested
* @return the number of {@code Configuration} objects associated with the specified
* {@code namespace}
*/
public long size(String namespace)
{
return configMap.getOrDefault(parseNamespace(namespace), Collections.emptySet()).size();
}
/**
* Returns {@code true} if this container contains no {@code Configuration} objects.
*
* @return {@code true} if this container contains no {@code Configuration} objects
* @since 1.0.0
*/
public boolean isEmpty()
{
return configMap.isEmpty();
}
/**
* Returns all of the namespaces defined inside this container.
*
* @return a set of namespaces
*/
public Collection getNamespaces()
{
return configMap.keySet();
}
}