TableExistsPrecondition.java

package liquibase.precondition.core;

import liquibase.changelog.DatabaseChangeLog;
import liquibase.changelog.ChangeSet;
import liquibase.database.Database;
import liquibase.exception.PreconditionErrorException;
import liquibase.exception.PreconditionFailedException;
import liquibase.exception.ValidationErrors;
import liquibase.exception.Warnings;
import liquibase.precondition.Precondition;
import liquibase.snapshot.DatabaseSnapshotGeneratorFactory;
import liquibase.util.StringUtils;

public class TableExistsPrecondition implements Precondition {
    private String schemaName;
    private String tableName;

    public String getSchemaName() {
        return schemaName;
    }

    public void setSchemaName(String schemaName) {
        this.schemaName = StringUtils.trimToNull(schemaName);
    }

    public String getTableName() {
        return tableName;
    }

    public void setTableName(String tableName) {
        this.tableName = tableName;
    }

        public Warnings warn(Database database) {
        return new Warnings();
    }

    public ValidationErrors validate(Database database) {
        return new ValidationErrors();
    }
    public void check(Database database, DatabaseChangeLog changeLog, ChangeSet changeSet) throws PreconditionFailedException, PreconditionErrorException {
        try {
            if (!DatabaseSnapshotGeneratorFactory.getInstance().getGenerator(database).hasTable(getSchemaName(), getTableName(), database)) {
                throw new PreconditionFailedException("Table "+database.escapeTableName(getSchemaName(), getTableName())+" does not exist", changeLog, this);
            }
        } catch (PreconditionFailedException e) {
            throw e;
        } catch (Exception e) {
            throw new PreconditionErrorException(e, changeLog, this);
        }
    }

    public String getName() {
        return "tableExists";
    }
}