IndexIdFactory.java

package com.txtr.hibernatedelta;

import java.util.Collections;
import java.util.List;

import org.apache.commons.lang3.StringUtils;

import com.txtr.hibernatedelta.model.ExplicitHibernateIndex;
import com.txtr.hibernatedelta.model.HibernateColumn;
import com.txtr.hibernatedelta.model.HibernateDatabase;
import com.txtr.hibernatedelta.model.HibernateIndexName;
import com.txtr.hibernatedelta.model.HibernateIndexNames;
import com.txtr.hibernatedelta.model.HibernateTable;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Ordering;

public class IndexIdFactory {

    private IndexIdFactory() {
    }

    public static void setIndexNames(HibernateDatabase newDatabase, HibernateIndexNames indexNames) {
        for (HibernateTable table : newDatabase.getTables()) {
            setIndexNames(table, indexNames);
        }
    }

    public static void setIndexNames(HibernateTable newTable, HibernateIndexNames indexNames) {

        List<ExplicitHibernateIndex> explicitIndexes = newTable.getExplicitIndexes();
        Collections.sort(explicitIndexes, Ordering.from(String.CASE_INSENSITIVE_ORDER).onResultOf(new Function<ExplicitHibernateIndex, String>() {
            @Override
            public String apply(ExplicitHibernateIndex input) {
                return StringUtils.join(input.getColumns(), ",");
            }
        }));

        for (HibernateColumn column : newTable.getColumns()) {
            if (needsIndexName(column)) {
                column.setIndexName(getIndexName(newTable, ImmutableList.of(column.getName()), indexNames));
            }
        }

        for (ExplicitHibernateIndex index : explicitIndexes) {
            if (index.getName() == null) {
                index.setIndexName(getIndexName(newTable, index.getColumns(), indexNames));
            }
        }
    }

    private static boolean needsIndexName(HibernateColumn column) {
        return column.getTargetTable() != null && column.getForeignKeyIndexName() == null;
    }

    private static HibernateIndexName getIndexName(HibernateTable table, List<String> columns, HibernateIndexNames indexNames) {
        HibernateIndexName oldName = indexNames.find(table.getName(), columns);
        if (oldName != null) {
            return oldName;
        }

        HibernateIndexName name = new HibernateIndexName(createIndexName(table.getIndexPrefix(), indexNames), table.getName(), columns);
        indexNames.getIndexNames().add(name);
        return name;
    }

    private static String createIndexName(String tableName, HibernateIndexNames indexNames) {
        int i = 1;
        while (true) {
            String indexName = tableName + i;

            if (indexNames.findByName(indexName) == null) {
                return indexName;
            }
            i++;
        }
    }
}