org.opentcs.data.TCSObject Maven / Gradle / Ivy
/**
* Copyright (c) The openTCS Authors.
*
* This program is free software and subject to the MIT license. (For details,
* see the licensing information (LICENSE.txt) you should have received with
* this copy of the software.)
*/
package org.opentcs.data;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static java.util.Objects.requireNonNull;
import java.util.Set;
import java.util.stream.Collectors;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
/**
* Describes the base behaviour of TCS data objects.
*
* @author Stefan Walter (Fraunhofer IML)
* @param The actual object class.
*/
public abstract class TCSObject>
implements Serializable {
/**
* A transient reference to this business object.
*/
protected TCSObjectReference reference;
/**
* A set of properties (key-value pairs) associated with this object.
*/
private final Map properties;
/**
* An unmodifiable view on this object's properties.
* This mainly exists for {@link #getProperties()}, as the alternative of
* creating ad-hoc copies or unmodifiable views can lead to performance issues
* related to garbage collection in situations where {@link #getProperties()}
* is called often.
*/
private final Map propertiesReadOnly;
/**
* The name of the business object.
*/
private final String name;
/**
* A history of events related to this object.
*/
private final ObjectHistory history;
/**
* Creates a new TCSObject.
*
* @param objectName The new object's name.
*/
protected TCSObject(@Nonnull String objectName) {
this(objectName, new HashMap<>(), new ObjectHistory());
}
/**
* Creates a new TCSObject.
*
* @param objectName The new object's name.
* @param properties A set of properties (key-value pairs) associated with this object.
* @param history A history of events related to this object.
*/
protected TCSObject(@Nonnull String objectName,
@Nonnull Map properties,
@Nonnull ObjectHistory history) {
this.name = requireNonNull(objectName, "objectName");
this.properties = mapWithoutNullValues(properties);
this.propertiesReadOnly = Collections.unmodifiableMap(this.properties);
this.reference = new TCSObjectReference<>(this);
this.history = requireNonNull(history, "history");
}
/**
* Returns this object's name.
*
* @return This object's name.
*/
@Nonnull
public String getName() {
return name;
}
/**
* Returns a transient/soft reference to this object.
*
* @return A transient/soft reference to this object.
*/
public TCSObjectReference getReference() {
return reference;
}
/**
* Returns an unmodifiable view on this object's properties.
*
* @return This object's properties.
*/
@Nonnull
public Map getProperties() {
return propertiesReadOnly;
}
/**
* Returns the property value for the given key.
* This is basically a shortcut for getProperties().get(key).
*
* @param key The property's key.
* @return The property value for the given key, or null, if there is none.
*/
@Nullable
public String getProperty(String key) {
return properties.get(key);
}
/**
* Creates a copy of this object, with the given property integrated.
*
* @param key The key of the property to be changed.
* @param value The new value of the property, or null, if the property is to be
* removed.
* @return A copy of this object, with the given property integrated.
*/
public abstract TCSObject withProperty(String key, String value);
/**
* Creates a copy of this object, with the given properties.
*
* @param properties The properties.
* @return A copy of this object, with the given properties.
*/
public abstract TCSObject withProperties(Map properties);
public ObjectHistory getHistory() {
return history;
}
/**
* Creates a copy of this object, with the given history entry integrated.
*
* @param entry The history entry to be integrated.
* @return A copy of this object, with the given history entry integrated.
*/
public abstract TCSObject withHistoryEntry(ObjectHistory.Entry entry);
/**
* Creates a copy of this object, with the given history.
*
* @param history The history.
* @return A copy of this object, with the given history.
*/
public abstract TCSObject withHistory(ObjectHistory history);
@Override
public String toString() {
return getClass().getSimpleName() + "{name=" + name + '}';
}
/**
* Checks if this object is equal to another one.
* Two TCSObjects are equal if both their IDs and their runtime
* classes are equal.
*
* @param obj The object to compare this one to.
* @return true if, and only if, obj is also a
* TCSObject and both its ID and runtime class equal those of
* this object.
*/
@Override
public boolean equals(Object obj) {
if (obj instanceof TCSObject) {
TCSObject other = (TCSObject) obj;
return this.getName().equals(other.getName()) && this.getClass().equals(other.getClass());
}
else {
return false;
}
}
/**
* Returns this object's hashcode.
* A TCSObject's hashcode is calculated by XORing its ID's
* hashcode and the hashcode of its runtime class's name.
*
* @return This object's hashcode.
*/
@Override
public int hashCode() {
return getName().hashCode()
^ this.getClass().getName().hashCode();
}
/**
* Returns a new map of this object's properties, with the given property integrated.
*
* @param key The key of the property to be changed.
* @param value The new value of the property, or null, if the property is to be
* removed.
* @return A new map of this object's properties, with the given property integrated.
*/
protected final Map propertiesWith(String key, String value) {
requireNonNull(key, "key");
Map result = new HashMap<>(properties);
if (value == null) {
result.remove(key);
}
else {
result.put(key, value);
}
return result;
}
/**
* Returns a new map with the entries from the given map but all entries with null
* values removed.
*
* @param The type of the map's keys.
* @param The type of the map's values.
* @param original The original map.
* @return A new map with the entries from the given map but all entries with null
* values removed.
*/
protected static final Map mapWithoutNullValues(Map original) {
requireNonNull(original, "original");
Map result = new HashMap<>();
for (Map.Entry entry : original.entrySet()) {
if (entry.getValue() != null) {
result.put(entry.getKey(), entry.getValue());
}
}
return result;
}
/**
* Returns a new list with the values from the given list but all null values
* removed.
*
* @param The type of the list's values.
* @param original The original list.
* @return A new list with the values from the given list but all null values
* removed.
*/
protected static final List listWithoutNullValues(List original) {
requireNonNull(original, "original");
return original.stream()
.filter(value -> value != null)
.collect(Collectors.toList());
}
/**
* Returns a new set with the values from the given set but all null values removed.
*
* @param The type of the set's values.
* @param original The original set.
* @return A new set with the values from the given set but all null values removed.
*/
protected static final Set setWithoutNullValues(Set original) {
requireNonNull(original, "original");
return original.stream()
.filter(value -> value != null)
.collect(Collectors.toSet());
}
}
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