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/*
* Copyright 2016 Davide Maestroni
*
* 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.github.dm.jrt.object.config;
import com.github.dm.jrt.core.util.ConstantConditions;
import com.github.dm.jrt.core.util.DeepEqualObject;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import static com.github.dm.jrt.core.util.Reflection.asArgs;
/**
* Class storing the object routine configuration.
*
* Each instance is immutable, thus, in order to modify an existing configuration, a new builder
* must be created from it.
*
* The configuration allows to set:
*
* - The set of fields which are shared by the target methods and need to be synchronized. By
* default the access to all the fields is protected. Note, however, that methods sharing the same
* fields will never be executed in parallel.
*
*
* Created by davide-maestroni on 04/20/2015.
*/
public final class ObjectConfiguration extends DeepEqualObject {
private static final DefaultConfigurable sDefaultConfigurable = new DefaultConfigurable();
private static final ObjectConfiguration sDefaultConfiguration = builder().buildConfiguration();
private final Set mFieldNames;
/**
* Constructor.
*
* @param fieldNames the shared field names.
*/
private ObjectConfiguration(@Nullable final Set fieldNames) {
super(asArgs(fieldNames));
mFieldNames = (fieldNames != null) ? Collections.unmodifiableSet(fieldNames) : null;
}
/**
* Returns an object configuration builder.
*
* @return the builder.
*/
@NotNull
public static Builder builder() {
return new Builder(sDefaultConfigurable);
}
/**
* Returns an object configuration builder initialized with the specified configuration.
*
* @param initialConfiguration the initial object configuration.
* @return the builder.
*/
@NotNull
public static Builder builderFrom(
@Nullable final ObjectConfiguration initialConfiguration) {
return (initialConfiguration == null) ? builder()
: new Builder(sDefaultConfigurable, initialConfiguration);
}
/**
* Returns a configuration with all the options set to their default.
*
* @return the configuration instance.
*/
@NotNull
public static ObjectConfiguration defaultConfiguration() {
return sDefaultConfiguration;
}
/**
* Returns an object configuration builder initialized with this configuration.
*
* @return the builder.
*/
@NotNull
public Builder builderFrom() {
return builderFrom(this);
}
/**
* Returns the shared field names (null by default).
*
* @param valueIfNotSet the default value if none was set.
* @return the field names.
*/
public Set getSharedFieldsOrElse(@Nullable final Set valueIfNotSet) {
final Set fieldNames = mFieldNames;
return (fieldNames != null) ? fieldNames : valueIfNotSet;
}
/**
* Interface defining a configurable object.
*
* @param the configurable object type.
*/
public interface Configurable {
/**
* Sets the specified configuration and returns the configurable instance.
*
* @param configuration the configuration.
* @return the configurable instance.
*/
@NotNull
TYPE apply(@NotNull ObjectConfiguration configuration);
}
/**
* Builder of object configurations.
*
* @param the configurable object type.
*/
public static final class Builder {
private final Configurable mConfigurable;
private Set mFieldNames;
/**
* Constructor.
*
* @param configurable the configurable instance.
*/
public Builder(@NotNull final Configurable configurable) {
mConfigurable = ConstantConditions.notNull("configurable instance", configurable);
}
/**
* Constructor.
*
* @param configurable the configurable instance.
* @param initialConfiguration the initial object configuration.
*/
public Builder(@NotNull final Configurable configurable,
@NotNull final ObjectConfiguration initialConfiguration) {
mConfigurable = ConstantConditions.notNull("configurable instance", configurable);
setConfiguration(initialConfiguration);
}
@NotNull
private static Set toSet(@NotNull final String[] values) {
final HashSet set = new HashSet();
Collections.addAll(set, values);
return set;
}
/**
* Applies this configuration and returns the configured object.
*
* @return the configured object.
*/
@NotNull
public TYPE configured() {
return mConfigurable.apply(buildConfiguration());
}
/**
* Applies the specified configuration to this builder. A null value means that all the
* configuration options will be reset to their default, otherwise only the non-default
* options will be applied.
*
* @param configuration the object configuration.
* @return this builder.
*/
@NotNull
public Builder with(@Nullable final ObjectConfiguration configuration) {
if (configuration == null) {
setConfiguration(defaultConfiguration());
return this;
}
final Set fieldNames = configuration.mFieldNames;
if (fieldNames != null) {
withSharedFields(fieldNames);
}
return this;
}
/**
* Sets the shared field names to empty, that is, no field is shared.
*
* @return this builder.
*/
@NotNull
public Builder withSharedFields() {
mFieldNames = Collections.emptySet();
return this;
}
/**
* Sets the shared field names. A null value means that all fields are shared.
*
* @param fieldNames the field names.
* @return this builder.
*/
@NotNull
public Builder withSharedFields(@Nullable final String... fieldNames) {
mFieldNames = (fieldNames != null) ? toSet(fieldNames) : null;
return this;
}
/**
* Sets the shared field names. A null value means that all fields are shared.
*
* @param fieldNames the field names.
* @return this builder.
*/
@NotNull
public Builder withSharedFields(@Nullable final Collection fieldNames) {
mFieldNames = (fieldNames != null) ? new HashSet(fieldNames) : null;
return this;
}
@NotNull
private ObjectConfiguration buildConfiguration() {
return new ObjectConfiguration(mFieldNames);
}
private void setConfiguration(@NotNull final ObjectConfiguration configuration) {
mFieldNames = configuration.mFieldNames;
}
}
/**
* Default configurable implementation.
*/
private static class DefaultConfigurable implements Configurable {
@NotNull
public ObjectConfiguration apply(@NotNull final ObjectConfiguration configuration) {
return configuration;
}
}
}