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SchemaCrawler is an open-source Java API that makes working with database metadata as easy as working with plain old Java objects. SchemaCrawler is also a database schema discovery and comprehension, and schema documentation tool. You can search for database schema objects using regular expressions, and output the schema and data in a readable text format. The output is designed to be diff-ed against other database schemas.
/*
*
* SchemaCrawler
* http://www.schemacrawler.com
* Copyright (c) 2000-2016, Sualeh Fatehi.
*
* This library is free software; you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Foundation;
* either version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
*/
package schemacrawler.utility;
import static java.util.Objects.requireNonNull;
import static sf.util.Utility.containsWhitespace;
import static sf.util.Utility.filterOutBlank;
import static sf.util.Utility.isBlank;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import java.util.function.Function;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Allows working with database object identifiers. All SQL 2003
* keywords are considered identifiers. If a live connection is
* provided, a list of valid identifiers is obtained from the database
* server as well. Several utility methods for looking up and quoting
* and unquoting identifiers are provided.
*/
public final class Identifiers
{
public static class Builder
{
/**
* Load a list of SQL 2003 reserved words, and normalize them by
* converting to uppercase.
*/
private static Collection loadSql2003ReservedWords()
{
final BufferedReader reader = new BufferedReader(new InputStreamReader(Identifiers.class
.getResourceAsStream("/sql2003_reserved_words.txt")));
final Set reservedWords = new HashSet<>();
reader.lines().filter(filterOutBlank).map(toUpperCase)
.forEach(reservedWord -> reservedWords.add(reservedWord));
if (reservedWords.isEmpty())
{
throw new RuntimeException("No SQL 2003 reserved words found");
}
return reservedWords;
}
/**
* Lookup a list of reserved words for a database system, using
* database metadata.
*/
private static Collection lookupReservedWords(final DatabaseMetaData metaData)
{
String sqlKeywords = "";
try
{
sqlKeywords = metaData.getSQLKeywords();
}
catch (final Exception e)
{
LOGGER.log(Level.WARNING,
"Could not retrieve SQL keywords metadata",
e);
}
return Stream.of(sqlKeywords.split(",")).filter(filterOutBlank)
.map(toUpperCase).collect(Collectors.toSet());
}
private String identifierQuoteString;
private final Collection reservedWords;
private Builder()
{
identifierQuoteString = "";
reservedWords = loadSql2003ReservedWords();
}
public Identifiers build()
{
return new Identifiers(this);
}
/**
* Constructs a list of database object identifiers from SQL 2003
* keywords, and from the database server. Also obtains the
* identifier quote string from the database server.
*
* @param connection
* Live database connection
* @throws SQLException
*/
public Builder withConnection(final Connection connection)
throws SQLException
{
requireNonNull(connection, "No connection provided");
final DatabaseMetaData metaData = requireNonNull(connection
.getMetaData(), "No database metadata obtained");
reservedWords.addAll(lookupReservedWords(metaData));
if (!isIdentifierQuoteStringSet())
{
final String metaDataIdentifierQuoteString = metaData
.getIdentifierQuoteString();
if (metaDataIdentifierQuoteString != null)
{
identifierQuoteString = metaDataIdentifierQuoteString;
}
}
return this;
}
/**
* Uses the string used to quote database object identifiers as
* provided.
*
* @param identifierQuoteString
* Identifier quote string override, or null if not
* overridden
*/
public Builder withIdentifierQuoteString(final String identifierQuoteString)
{
requireNonNull(identifierQuoteString,
"No identifier quote string provided");
this.identifierQuoteString = identifierQuoteString;
return this;
}
private boolean isIdentifierQuoteStringSet()
{
return identifierQuoteString == null || !identifierQuoteString.isEmpty();
}
}
private static final Logger LOGGER = Logger
.getLogger(Identifiers.class.getName());
private static final Function toUpperCase = word -> word
.trim().toUpperCase();
private static final Pattern isIdentifierPattern = Pattern
.compile("^[\\p{Nd}\\p{L}\\p{M}_]*$");
private static final Pattern isNumericPattern = Pattern.compile("^\\p{Nd}*$");
public static Builder identifiers()
{
return new Builder();
}
/**
* Checks if the name is valid database object identifier, according
* to the rules of most databases.
*
* @param name
* Name to check.
* @return Whether the name is valid database object identifier.
*/
private static boolean isIdentifier(final String name)
{
if (isBlank(name))
{
return false;
}
else
{
return isIdentifierPattern.matcher(name).matches();
}
}
/**
* Checks if the name is composed of all numbers.
*
* @param name
* Name to check.
* @return Whether the string consists of all numbers.
*/
private static boolean isNumeric(final String name)
{
if (isBlank(name))
{
return false;
}
else
{
return isNumericPattern.matcher(name).matches();
}
}
private final String identifierQuoteString;
private final Collection reservedWords;
private Identifiers(final Builder builder)
{
identifierQuoteString = builder.identifierQuoteString;
reservedWords = builder.reservedWords;
}
/**
* Gets the string used to quote database object identifiers, as
* provided by the database server, or as overridden by the caller.
*
* @return Identifier quote string
*/
public String getIdentifierQuoteString()
{
return identifierQuoteString;
}
/**
* Get a list of reserved words, normalized to uppercase.
*/
public Collection getReservedWords()
{
return new HashSet<>(reservedWords);
}
/**
* Checks if an identifier name is quoted using the identifier quote
* character.
*
* @param name
* Identifier name to check
* @return Whether the identifier name is quoted
*/
public boolean isQuotedName(final String name)
{
if (isBlank(name) || identifierQuoteString.isEmpty())
{
return false;
}
final int quoteLength = identifierQuoteString.length();
return name.startsWith(identifierQuoteString)
&& name.endsWith(identifierQuoteString)
&& name.length() >= quoteLength * 2;
}
/**
* Checks if a given word is a reserved word. Searches are
* case-insensitive.
*
* @param word
* Word to check
* @return Whether the given word is reserved
*/
public boolean isReservedWord(final String word)
{
return filterOutBlank.test(word)
&& reservedWords.contains(toUpperCase.apply(word));
}
/**
* Checks if a given identifier name needs to be quoted. It uses
* generalized rules which are common across the majority of
* databases.
*
* @param name
* Identifier name to check
* @return Whether the given name needs to be quoted
*/
public boolean isToBeQuoted(final String name)
{
if (name == null || name.isEmpty() || isQuotedName(name))
{
return false;
}
else
{
return containsWhitespace(name) || isNumeric(name)
|| containsSpecialCharacters(name) || isReservedWord(name);
}
}
/**
* Quotes an identifier name using the identifier quote string. Does
* not quote the identifier name if quoting is not required, per
* generalized database rules.
*
* @param name
* Identifier name to quote
* @return Identifier name after quoting it, or the original name if
* quoting is not required
*/
public String quotedName(final String name)
{
final String quotedName;
if (isToBeQuoted(name))
{
quotedName = identifierQuoteString + name + identifierQuoteString;
}
else
{
quotedName = name;
}
return quotedName;
}
/**
* Remove quotes from an identifier name using the identifier quote
* string. Returns the original name if it was not quoted.
*
* @param name
* Identifier name to remove quotes from
* @return Identifier name after quoting it, or the original name if
* quoting is not required
*/
public String unquotedName(final String name)
{
if (isBlank(name))
{
return name;
}
final String unquotedName;
final int quoteLength = identifierQuoteString.length();
if (isQuotedName(name))
{
unquotedName = name.substring(quoteLength, name.length() - quoteLength);
}
else
{
unquotedName = name;
}
return unquotedName;
}
/**
* Checks if an identifier name contains characters other than the
* ones allowed by most databases for identifier names.
*/
private boolean containsSpecialCharacters(final String name)
{
return !isIdentifier(name);
}
}
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