liquibase.ext.hibernate.snapshot.IndexSnapshotGenerator Maven / Gradle / Ivy

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package liquibase.ext.hibernate.snapshot;

import liquibase.Scope;
import liquibase.exception.DatabaseException;
import liquibase.snapshot.DatabaseSnapshot;
import liquibase.snapshot.InvalidExampleException;
import liquibase.structure.DatabaseObject;
import liquibase.structure.core.*;

import java.util.Iterator;

public class IndexSnapshotGenerator extends HibernateSnapshotGenerator {

    private static final String HIBERNATE_ORDER_ASC = "asc";
    private static final String HIBERNATE_ORDER_DESC = "desc";

    @SuppressWarnings("unchecked")
    public IndexSnapshotGenerator() {
        super(Index.class, new Class[]{Table.class, ForeignKey.class, UniqueConstraint.class});
    }

    @Override
    protected DatabaseObject snapshotObject(DatabaseObject example, DatabaseSnapshot snapshot) throws DatabaseException, InvalidExampleException {
        if (example.getSnapshotId() != null) {
            return example;
        }
        Relation table = ((Index) example).getRelation();
        org.hibernate.mapping.Table hibernateTable = findHibernateTable(table, snapshot);
        if (hibernateTable == null) {
            return example;
        }
        Iterator indexIterator = hibernateTable.getIndexIterator();
        while (indexIterator.hasNext()) {
            org.hibernate.mapping.Index hibernateIndex = indexIterator.next();
            Index index = new Index();
            index.setRelation(table);
            index.setName(hibernateIndex.getName());
            index.setUnique(isUniqueIndex(hibernateIndex));
            Iterator columnIterator = hibernateIndex.getColumnIterator();
            while (columnIterator.hasNext()) {
                org.hibernate.mapping.Column hibernateColumn = columnIterator.next();
                String hibernateOrder = hibernateIndex.getColumnOrderMap().get(hibernateColumn);
                Boolean descending = HIBERNATE_ORDER_ASC.equals(hibernateOrder)
                        ? Boolean.FALSE
                        : (HIBERNATE_ORDER_DESC.equals(hibernateOrder) ? Boolean.TRUE : null);
                index.getColumns().add(new Column(hibernateColumn.getName()).setRelation(table).setDescending(descending));
            }

            if (index.getColumnNames().equalsIgnoreCase(((Index) example).getColumnNames())) {
                Scope.getCurrentScope().getLog(getClass()).info("Found index " + index.getName());
                table.getIndexes().add(index);
                return index;
            }
        }
        return example;

    }

    @Override
    protected void addTo(DatabaseObject foundObject, DatabaseSnapshot snapshot) throws DatabaseException, InvalidExampleException {
        if (!snapshot.getSnapshotControl().shouldInclude(Index.class)) {
            return;
        }
        if (foundObject instanceof Table) {
            Table table = (Table) foundObject;
            org.hibernate.mapping.Table hibernateTable = findHibernateTable(table, snapshot);
            if (hibernateTable == null) {
                return;
            }
            Iterator indexIterator = hibernateTable.getIndexIterator();
            while (indexIterator.hasNext()) {
                org.hibernate.mapping.Index hibernateIndex =  indexIterator.next();
                Index index = new Index();
                index.setRelation(table);
                index.setName(hibernateIndex.getName());
                index.setUnique(isUniqueIndex(hibernateIndex));
                Iterator columnIterator = hibernateIndex.getColumnIterator();
                while (columnIterator.hasNext()) {
                    org.hibernate.mapping.Column hibernateColumn = columnIterator.next();
                    String hibernateOrder = hibernateIndex.getColumnOrderMap().get(hibernateColumn);
                    Boolean descending = HIBERNATE_ORDER_ASC.equals(hibernateOrder)
                            ? Boolean.FALSE
                            : (HIBERNATE_ORDER_DESC.equals(hibernateOrder) ? Boolean.TRUE : null);
                    index.getColumns().add(new Column(hibernateColumn.getName()).setRelation(table).setDescending(descending));
                }
                Scope.getCurrentScope().getLog(getClass()).info("Found index " + index.getName());
                table.getIndexes().add(index);
            }
        }
    }

    private Boolean isUniqueIndex(org.hibernate.mapping.Index hibernateIndex) {
        /*
        This seems to be necessary to explicitly tell liquibase that there's no
        actual diff in certain non-unique indexes
        */
        if (hibernateIndex.getColumnSpan() == 1) {
            org.hibernate.mapping.Column col = hibernateIndex.getColumnIterator().next();
            return col.isUnique();
        } else {
            /*
            It seems that because Hibernate does not implement the unique property of the Jpa composite index,
            the diff command appears 'diffence', because the unique property of the entity index is 'null',
            and the value read from the database is 'false', resulting in the generated changeSet after the Drop and
            Recreate Index.
            */
            return false;
        }
    }
}