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JaVers - object auditing and diff framework for Java
package org.javers.core;
import org.javers.common.collections.Lists;
import org.javers.common.string.PrettyValuePrinter;
import org.javers.common.validation.Validate;
import org.javers.core.commit.CommitMetadata;
import org.javers.core.diff.Change;
import org.javers.core.diff.changetype.PropertyChange;
import org.javers.core.metamodel.object.GlobalId;
import org.javers.repository.jql.JqlQuery;
import java.io.Serializable;
import java.util.*;
import java.util.stream.Collectors;
import static java.util.Collections.unmodifiableList;
import static java.util.stream.Collectors.groupingBy;
import static java.util.stream.Collectors.toList;
import static org.javers.common.validation.Validate.argumentIsNotNull;
/**
* Convenient wrapper for the list of Changes returned by {@link Javers#findChanges(JqlQuery)}.
*
* Can be used as List<Change>,
* but also provides additional methods:
*
*
*
* - {@link #groupByCommit()}, {@link #groupByObject()} —
* allow traversing over the list of Changes grouped by commits
* and grouped by objects
* - {@link #getChangesByType(Class)} — a subset of Changes with a given type
*
- {@link #prettyPrint()} — prints Changes to a String, nicely formatted, user-readable style
*
- {@link #devPrint()} — prints Changes to a String, simple and technical style
*
*
* @see http://javers.org/documentation/repository-examples/#change-log
* @since 3.9
*/
public class Changes extends AbstractList implements Serializable {
private final List changes;
private final transient PrettyValuePrinter valuePrinter;
public Changes(List changes, PrettyValuePrinter valuePrinter) {
Validate.argumentsAreNotNull(changes, valuePrinter);
this.changes = Collections.unmodifiableList(changes);
this.valuePrinter = valuePrinter;
}
/**
* Returns changes grouped by commits.
*
*
* When formatting a changelog,
* usually you need to group changes by commits and then by objects.
*
*
* A simple changelog, like {@link #devPrint()}, can be printed by this code:
*
*
*
* changes.groupByCommit().forEach(byCommit -> {
* System.out.println("commit " + byCommit.getCommit().getId());
* byCommit.groupByObject().forEach(byObject -> {
* System.out.println(" changes on " + byObject.getGlobalId().value() + ":");
* byObject.get().forEach(change -> System.out.println(" - " + change));
* });
* });
*
*
* @since 3.9
*/
public List groupByCommit() {
if (changes.size() == 0) {
return Collections.emptyList();
}
if (!changes.get(0).getCommitMetadata().isPresent()) {
return Lists.immutableListOf(
new ChangesByCommit(CommitMetadata.nullObject(), changes, valuePrinter)
);
}
Map> changesByCommit = changes.stream().collect(
groupingBy(c -> c.getCommitMetadata().orElseThrow( () -> new IllegalStateException("No CommitMetadata in this Change")),
() -> new LinkedHashMap<>(), toList()));
List result = new ArrayList<>();
changesByCommit.forEach((k,v) -> {
result.add(new ChangesByCommit(k, v, valuePrinter));
});
return unmodifiableList(result);
}
public List getPropertyChanges(String propertyName) {
return (List)changes.stream()
.filter(it -> it instanceof PropertyChange
&& ((PropertyChange) it).getPropertyName().equals(propertyName))
.collect(Collectors.toList());
}
/**
* Changes grouped by entities.
*
*
* See example in {@link #groupByCommit()}
*
* @since 3.9
*/
public List groupByObject() {
Map> changesByObject = changes.stream().collect(
groupingBy(c -> c.getAffectedGlobalId().masterObjectId()));
List result = new ArrayList<>();
changesByObject.forEach((k, v) -> {
result.add(new ChangesByObject(k, v, valuePrinter));
});
return unmodifiableList(result);
}
@Override
public Change get(int index) {
return changes.get(index);
}
@Override
public int size() {
return changes.size();
}
/**
* Returns a subset of Changes with a given type
*/
public List getChangesByType(final Class type) {
argumentIsNotNull(type);
return (List) unmodifiableList(
changes.stream().filter(input -> type.isAssignableFrom(input.getClass())).collect(Collectors.toList()));
}
/**
* Delegates to {@link #devPrint()}.
* See {@link #prettyPrint()}
*/
@Override
public String toString() {
return devPrint();
}
/**
* Prints the list of Changes to a nicely formatted String.
* Can be used on GUI to show Changes to your users.
*
* Example:
*
*
*
* Changes:
* Commit 2.00 done by author at 14 Mar 2021, 12:37:37 :
* * changes on Employee/Frodo :
* - 'lastPromotionDate' = '14.37.2021 12:37'
* - 'performance' map changes :
* · entry ['1' : 'bb'] -> ['1' : 'aa']
* · entry ['2' : 'bb'] added
* · entry ['3' : 'aa'] removed
* - 'position' = 'Hero'
* - 'postalAddress.city' = 'Shire'
* - 'primaryAddress.city' changed: 'Shire' -> 'Mordor'
* - 'primaryAddress.street' = 'Some Street'
* - 'salary' changed: '10000' -> '12000'
* - 'skills' collection changes :
* · 'agile coaching' added
* - 'subordinates' collection changes :
* 0. 'Employee/Sam' added
* * new object: Employee/Sam
* - 'name' = 'Sam'
* - 'salary' = '10000'
* Commit 1.00 done by author at 14 Mar 2021, 12:37:37 :
* * new object: Employee/Frodo
* - 'name' = 'Frodo'
* - 'performance' map changes :
* · entry ['1' : 'bb'] added
* · entry ['3' : 'aa'] added
* - 'primaryAddress.city' = 'Shire'
* - 'salary' = '10000'
* - 'skills' collection changes :
* · 'management' added
*
*/
public final String prettyPrint() {
StringBuilder b = new StringBuilder();
b.append("Changes:\n");
for (ChangesByCommit c : groupByCommit()){
b.append(c.prettyPrint());
}
return b.toString();
}
/**
* Prints the Changes in a technical style.
* Useful for development and debugging.
*
* You can use the implementation of this method as a template to create your own changelog
* (if {@link #prettyPrint()} is not ok for you).
*
*
* Example:
*
*
* Changes (18):
* commit 2.00
* changes on Employee/Frodo :
* - ValueChange{ property: 'city', left:'Shire', right:'Mordor' }
* - ValueChange{ property: 'street', left:'', right:'Some Street' }
* - ValueChange{ property: 'position', left:'', right:'Hero' }
* - ValueChange{ property: 'salary', left:'10000', right:'12000' }
* - ListChange{ property: 'subordinates', elementChanges:1 }
* - SetChange{ property: 'skills', elementChanges:1 }
* - MapChange{ property: 'performance', entryChanges:3 }
* - ValueChange{ property: 'lastPromotionDate', left:'', right:'14 Mar 2021, 12:58:06+0100' }
* - InitialValueChange{ property: 'city', left:'', right:'Shire' }
* changes on Employee/Sam :
* - NewObject{ new object: Employee/Sam }
* - InitialValueChange{ property: 'name', left:'', right:'Sam' }
* - InitialValueChange{ property: 'salary', left:'', right:'10000' }
* commit 1.00
* changes on Employee/Frodo :
* - InitialValueChange{ property: 'city', left:'', right:'Shire' }
* - NewObject{ new object: Employee/Frodo }
* - InitialValueChange{ property: 'name', left:'', right:'Frodo' }
* - InitialValueChange{ property: 'salary', left:'', right:'10000' }
* - SetChange{ property: 'skills', elementChanges:1 }
* - MapChange{ property: 'performance', entryChanges:2 }
*
*/
public String devPrint() {
StringBuilder b = new StringBuilder();
b.append("Changes ("+size()+"):\n");
groupByCommit().forEach(byCommit -> {
b.append("commit " + byCommit.getCommit().getId() + " \n");
byCommit.groupByObject().forEach(byObject -> {
b.append("* changes on " + byObject.getGlobalId().value() + " :\n");
byObject.get().forEach(change -> b.append(" - " + change + " \n"));
});
});
return b.toString();
}
}