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JDBC Driver for the Firebird RDBMS
/*
* Firebird Open Source JavaEE Connector - JDBC Driver
*
* Distributable under LGPL license.
* You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
*
* This program 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
* LGPL License for more details.
*
* This file was created by members of the firebird development team.
* All individual contributions remain the Copyright (C) of those
* individuals. Contributors to this file are either listed here or
* can be obtained from a source control history command.
*
* All rights reserved.
*/
package org.firebirdsql.encodings;
import org.firebirdsql.logging.Logger;
import org.firebirdsql.logging.LoggerFactory;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.StandardCharsets;
import java.nio.charset.UnsupportedCharsetException;
/**
* Definition of a Firebird encoding. This is the default implementation of {@link EncodingDefinition}.
*
* @author Mark Rotteveel
* @since 3.0
*/
public final class DefaultEncodingDefinition implements EncodingDefinition {
private static final Logger logger = LoggerFactory.getLogger(DefaultEncodingDefinition.class);
/**
* Marker object to indicate the encoding field of an instance hasn't been initialized yet
* (since null is a valid initialization).
*/
private static final Encoding NOT_INITIALIZED = new EncodingGeneric(null);
private final String charsetName;
private final String firebirdEncodingName;
private final int maxBytesPerChar;
private final int firebirdCharacterSetId;
private final boolean firebirdOnly;
private Encoding encoding = NOT_INITIALIZED;
private Charset charset;
/**
* Initializes an instance of DefaultEncodingDefinition.
*
* @param firebirdEncodingName
* Name of the Firebird encoding
* @param charset
* Java {@link Charset} instance ({@code null} for information-only instances)
* @param maxBytesPerChar
* Maximum number of bytes per character (eg 1 for ISO8859_1, 4 for UTF8, 3 for UNICODE-FSS)
* @param firebirdCharacterSetId
* Firebird character set id
* @param firebirdOnly
* Mapping only applies from Firebird to Java, but not from Java to Firebird (eg Firebird UNICODE-FSS maps
* to Java UTF-8, but Java UTF-8 does not map to Firebird UNICODE-FSS (but to Firebird UTF8)
*/
public DefaultEncodingDefinition(String firebirdEncodingName, Charset charset, int maxBytesPerChar,
int firebirdCharacterSetId, boolean firebirdOnly) {
this(firebirdEncodingName, charset != null ? charset.name() : null, maxBytesPerChar, firebirdCharacterSetId,
firebirdOnly);
this.charset = charset;
}
/**
* Initializes an instance of DefaultEncodingDefinition.
*
* The actual Java character set is loaded on-demand. If the provided name cannot be resolved to a {@link Charset}
* at on-demand load time, it will be handled as information-only.
*
*
* @param firebirdEncodingName
* Name of the Firebird encoding
* @param charsetName
* Java character set name, or {@code null} for information-only instances
* @param maxBytesPerChar
* Maximum number of bytes per character (eg 1 for ISO8859_1, 4 for UTF8, 3 for UNICODE-FSS)
* @param firebirdCharacterSetId
* Firebird character set id
* @param firebirdOnly
* Mapping only applies from Firebird to Java, but not from Java to Firebird (eg Firebird UNICODE-FSS maps
* to Java UTF-8, but Java UTF-8 does not map to Firebird UNICODE-FSS (but to Firebird UTF8)
*/
public DefaultEncodingDefinition(String firebirdEncodingName, String charsetName, int maxBytesPerChar,
int firebirdCharacterSetId, boolean firebirdOnly) {
this.firebirdEncodingName = firebirdEncodingName;
this.charsetName = charsetName;
if (charsetName == null) {
encoding = null;
}
this.maxBytesPerChar = maxBytesPerChar;
this.firebirdOnly = firebirdOnly;
this.firebirdCharacterSetId = firebirdCharacterSetId;
}
@Override
public int getMaxBytesPerChar() {
return maxBytesPerChar;
}
@Override
public String getJavaEncodingName() {
return charsetName;
}
@Override
public Charset getJavaCharset() {
if (charset == null && encoding == NOT_INITIALIZED) {
// We intentionally don't use synchronization or volatile here
// Multiple initialization might be a bit wasteful, but it has no other side effects
initCharset();
}
return charset;
}
@Override
public String getFirebirdEncodingName() {
return firebirdEncodingName;
}
@Override
public int getFirebirdCharacterSetId() {
return firebirdCharacterSetId;
}
@Override
public boolean isFirebirdOnly() {
return firebirdOnly;
}
@Override
public boolean isInformationOnly() {
return charsetName == null || getJavaCharset() == null;
}
/**
* Returns the {@link Encoding} instance for this definition. The same object is returned
* each time this method is called.
*/
@Override
public Encoding getEncoding() {
if (encoding == NOT_INITIALIZED) {
// We intentionally don't use synchronization or volatile here
// Multiple initialization might be a bit wasteful, but it has no other side effects
initEncoding();
}
return encoding;
}
@Override
public String toString() {
return "[" +
"firebirdEncodingName='" + getFirebirdEncodingName() + "'," +
"javaEncodingName='" + getJavaEncodingName() + "'," +
"maxBytesPerChar=" + getMaxBytesPerChar() + "," +
"firebirdOnly=" + isFirebirdOnly() + "," +
"firebirdCharacterSetId=" + getFirebirdCharacterSetId() +
"]";
}
private void initCharset() {
try {
charset = Charset.forName(charsetName);
} catch (IllegalCharsetNameException | UnsupportedCharsetException e) {
// Prevent further attempts
encoding = null;
logger.warn(String.format("charsetName=\"%s\" specified for Firebird encoding \"%s\" is an illegal or "
+ "unsupported character set name, handling as information-only",
charsetName, firebirdEncodingName), e);
}
}
private void initEncoding() {
if (isInformationOnly()) {
encoding = null;
} else if (getMaxBytesPerChar() == 1
// Exception for NONE / UTF-8 (prevents it from creating a single byte encoding)
&& !("NONE".equals(firebirdEncodingName) && StandardCharsets.UTF_8.equals(getJavaCharset()))) {
encoding = new EncodingSingleByte(getJavaCharset());
} else {
encoding = new EncodingGeneric(getJavaCharset());
}
}
}