com.mysql.cj.util.LazyString Maven / Gradle / Ivy
/*
* Copyright (c) 2015, 2020, Oracle and/or its affiliates.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 2.0, as published by the
* Free Software Foundation.
*
* This program is also distributed with certain software (including but not
* limited to OpenSSL) that is licensed under separate terms, as designated in a
* particular file or component or in included license documentation. The
* authors of MySQL hereby grant you an additional permission to link the
* program and your derivative works with the separately licensed software that
* they have included with MySQL.
*
* Without limiting anything contained in the foregoing, this file, which is
* part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
* version 1.0, a copy of which can be found at
* http://oss.oracle.com/licenses/universal-foss-exception.
*
* 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 GNU General Public License, version 2.0,
* for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.cj.util;
import java.util.function.Supplier;
/**
* A lazy string that can take a byte buffer and encoding and interpret it as a string if/when requested. The string is cached and saved for any further
* requests. "NULL" values can be represented by a 0-len string or a null passed to LazyString(String).
*/
public class LazyString implements Supplier {
private String string; // the string, if one has been created
private byte[] buffer;
private int offset;
private int length;
private String encoding;
public LazyString(String string) {
// convenience for wrapping
this.string = string;
}
public LazyString(byte[] buffer, int offset, int length, String encoding) {
this.buffer = buffer;
this.offset = offset;
this.length = length;
this.encoding = encoding;
}
public LazyString(byte[] buffer, int offset, int length) {
this.buffer = buffer;
this.offset = offset;
this.length = length;
}
private String createAndCacheString() {
if (this.length > 0) {
this.string = this.encoding == null ? StringUtils.toString(this.buffer, this.offset, this.length)
: StringUtils.toString(this.buffer, this.offset, this.length, this.encoding);
}
// this can be NULL for 0-len strings
return this.string;
}
@Override
public String toString() {
if (this.string != null) {
return this.string;
}
return createAndCacheString();
}
public int length() {
if (this.string != null) {
return this.string.length();
}
return this.length;
}
@Override
public String get() {
return toString();
}
}