net.lshift.hibernate.migrations.SQLStringHelpers.java Source code

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Here is the source code for net.lshift.hibernate.migrations.SQLStringHelpers.java

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/**
 * Copyright (C) 2011 LShift Ltd.
 *
 * 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 net.lshift.hibernate.migrations;

import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.Dialect;
import org.hibernate.mapping.Column;
import org.hibernate.mapping.Table;

import java.sql.Types;

/**
 * Helpers for various string manipulation operations.
 */
public class SQLStringHelpers {

    /**
     * Generates an identity column string
     * @throws UnsupportedOperationException If the underlying dialect does not support identity columns*
    */
    public static String generateIdentityColumnString(Dialect dialect, Column col) {

        if (!dialect.supportsIdentityColumns()) {
            String dialectName = Environment.getProperties().getProperty(Environment.DIALECT);
            throw new UnsupportedOperationException(dialectName + " does not support identity columns");
        }

        StringBuilder buffer = new StringBuilder();

        buffer.append(col.getQuotedName(dialect)).append(" ");

        // to support dialects that have their own identity data type
        if (dialect.hasDataTypeInIdentityColumn()) {
            buffer.append(getTypeName(dialect, col));
        }
        buffer.append(' ').append(dialect.getIdentityColumnString(col.getSqlTypeCode()));

        return buffer.toString();
    }

    public static String generateNonIdentityColumnString(Dialect dialect, Column col) {

        StringBuilder buffer = new StringBuilder();

        buffer.append(col.getQuotedName(dialect)).append(" ");
        buffer.append(getTypeName(dialect, col));

        buffer.append(" not null");

        return buffer.toString();
    }

    public static String generateColumnString(Dialect dialect, Column col, boolean newTable) {
        StringBuilder buffer = new StringBuilder();

        buffer.append(col.getQuotedName(dialect)).append(" ");
        buffer.append(getTypeName(dialect, col));

        if (!newTable && col.getDefaultValue() == null && !col.isNullable()) {
            throw new IllegalArgumentException(
                    "Cannot have a null default value for a non-nullable column when altering a table: " + col);
        }
        if (col.getDefaultValue() != null) {
            String defaultQuote;

            buffer.append(" default ");
            if (col.getSqlTypeCode() == Types.VARCHAR)
                defaultQuote = "'";
            else
                defaultQuote = "";

            buffer.append(defaultQuote);
            buffer.append(col.getDefaultValue());
            buffer.append(defaultQuote);
        }
        if (col instanceof VirtualColumn) {
            buffer.append(String.format(" GENERATED ALWAYS AS (%s) VIRTUAL", ((VirtualColumn) col).getGenerator()));
        }

        // HSQL Doesn't like the not null coming before the default stanza
        if (!col.isNullable()) {
            buffer.append(" not null");
        }

        return buffer.toString();
    }

    /**
     * Note to the unassuming maintenance developer:
     *
     * What happens with Oracle a dialect is when a varchar2 is larger than 4000,
     * the type name returned for java.sql.Type.VARCHAR is a long, which can be very confusing.
     *
     * I'm not sure that this is significant enough to warrant patching.
     *
     */
    private static String getTypeName(Dialect dialect, Column col) {
        return dialect.getTypeName(col.getSqlTypeCode(), col.getLength(), col.getPrecision(), col.getScale());
    }

    public static String qualifyName(Configuration config, Dialect dialect, String table) {
        String defaultCatalog = config.getProperties().getProperty(Environment.DEFAULT_CATALOG);
        String defaultSchema = config.getProperties().getProperty(Environment.DEFAULT_SCHEMA);
        return new Table(table).getQualifiedName(dialect, defaultCatalog, defaultSchema);
    }

    public static String maybeBracketTerm(String term, boolean bracket) {
        if (bracket)
            return "(" + term + ")";
        return term;
    }
}