java.io.StringWriter Maven / Gradle / Ivy
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
/**
* A character stream that collects its output in a string buffer, which can
* then be used to construct a string.
*
* Closing a StringWriter has no effect. The methods in this class
* can be called after the stream has been closed without generating an
* IOException.
*
* @author Mark Reinhold
* @since JDK1.1
*/
public class StringWriter extends Writer {
private StringBuffer buf;
/**
* Create a new string writer using the default initial string-buffer
* size.
*/
public StringWriter() {
buf = new StringBuffer();
lock = buf;
}
/**
* Create a new string writer using the specified initial string-buffer
* size.
*
* @param initialSize
* The number of char values that will fit into this buffer
* before it is automatically expanded
*
* @throws IllegalArgumentException
* If initialSize is negative
*/
public StringWriter(int initialSize) {
if (initialSize < 0) {
throw new IllegalArgumentException("Negative buffer size");
}
buf = new StringBuffer(initialSize);
lock = buf;
}
/**
* Write a single character.
*/
public void write(int c) {
buf.append((char) c);
}
/**
* Write a portion of an array of characters.
*
* @param cbuf Array of characters
* @param off Offset from which to start writing characters
* @param len Number of characters to write
*/
public void write(char cbuf[], int off, int len) {
if ((off < 0) || (off > cbuf.length) || (len < 0) ||
((off + len) > cbuf.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
buf.append(cbuf, off, len);
}
/**
* Write a string.
*/
public void write(String str) {
buf.append(str);
}
/**
* Write a portion of a string.
*
* @param str String to be written
* @param off Offset from which to start writing characters
* @param len Number of characters to write
*/
public void write(String str, int off, int len) {
buf.append(str.substring(off, off + len));
}
/**
* Appends the specified character sequence to this writer.
*
*
An invocation of this method of the form out.append(csq)
* behaves in exactly the same way as the invocation
*
*
* out.write(csq.toString())
*
* Depending on the specification of toString for the
* character sequence csq, the entire sequence may not be
* appended. For instance, invoking the toString method of a
* character buffer will return a subsequence whose content depends upon
* the buffer's position and limit.
*
* @param csq
* The character sequence to append. If csq is
* null, then the four characters "null" are
* appended to this writer.
*
* @return This writer
*
* @since 1.5
*/
public StringWriter append(CharSequence csq) {
if (csq == null)
write("null");
else
write(csq.toString());
return this;
}
/**
* Appends a subsequence of the specified character sequence to this writer.
*
*
An invocation of this method of the form out.append(csq, start,
* end) when csq is not null, behaves in
* exactly the same way as the invocation
*
*
* out.write(csq.subSequence(start, end).toString())
*
* @param csq
* The character sequence from which a subsequence will be
* appended. If csq is null, then characters
* will be appended as if csq contained the four
* characters "null".
*
* @param start
* The index of the first character in the subsequence
*
* @param end
* The index of the character following the last character in the
* subsequence
*
* @return This writer
*
* @throws IndexOutOfBoundsException
* If start or end are negative, start
* is greater than end, or end is greater than
* csq.length()
*
* @since 1.5
*/
public StringWriter append(CharSequence csq, int start, int end) {
CharSequence cs = (csq == null ? "null" : csq);
write(cs.subSequence(start, end).toString());
return this;
}
/**
* Appends the specified character to this writer.
*
* An invocation of this method of the form out.append(c)
* behaves in exactly the same way as the invocation
*
*
* out.write(c)
*
* @param c
* The 16-bit character to append
*
* @return This writer
*
* @since 1.5
*/
public StringWriter append(char c) {
write(c);
return this;
}
/**
* Return the buffer's current value as a string.
*/
public String toString() {
return buf.toString();
}
/**
* Return the string buffer itself.
*
* @return StringBuffer holding the current buffer value.
*/
public StringBuffer getBuffer() {
return buf;
}
/**
* Flush the stream.
*/
public void flush() {
}
/**
* Closing a StringWriter has no effect. The methods in this
* class can be called after the stream has been closed without generating
* an IOException.
*/
public void close() throws IOException {
}
}