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Diffstat (limited to 'libjava/classpath/java/io/CharArrayWriter.java')
-rw-r--r-- | libjava/classpath/java/io/CharArrayWriter.java | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/libjava/classpath/java/io/CharArrayWriter.java b/libjava/classpath/java/io/CharArrayWriter.java new file mode 100644 index 0000000..f9b338f --- /dev/null +++ b/libjava/classpath/java/io/CharArrayWriter.java @@ -0,0 +1,274 @@ +/* CharArrayWriter.java -- Write chars to a buffer + Copyright (C) 1998, 1999, 2001, 2002, 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.io; + +/** + * This class allows data to be written to a char array buffer and + * and then retrieved by an application. The internal char array + * buffer is dynamically resized to hold all the data written. Please + * be aware that writing large amounts to data to this stream will + * cause large amounts of memory to be allocated. + * <p> + * The size of the internal buffer defaults to 32 and it is resized + * in increments of 1024 chars. This behavior can be over-ridden by using the + * following two properties: + * <p> + * <ul> + * <li><xmp>gnu.java.io.CharArrayWriter.initialBufferSize</xmp></li> + * <li><xmp>gnu.java.io.CharArrayWriter.bufferIncrementSize</xmp></li> + * </ul> + * <p> + * There is a constructor that specified the initial buffer size and + * that is the preferred way to set that value because it it portable + * across all Java class library implementations. + * <p> + * + * @author Aaron M. Renn (arenn@urbanophile.com) + * @author Tom Tromey (tromey@cygnus.com) + */ +public class CharArrayWriter extends Writer +{ + /** + * The default initial buffer size + */ + private static final int DEFAULT_INITIAL_BUFFER_SIZE = 32; + + /** + * This method initializes a new <code>CharArrayWriter</code> with + * the default buffer size of 32 chars. If a different initial + * buffer size is desired, see the constructor + * <code>CharArrayWriter(int size)</code>. + */ + public CharArrayWriter () + { + this (DEFAULT_INITIAL_BUFFER_SIZE); + } + + /** + * This method initializes a new <code>CharArrayWriter</code> with + * a specified initial buffer size. + * + * @param size The initial buffer size in chars + */ + public CharArrayWriter (int size) + { + super (); + buf = new char[size]; + } + + /** + * Closes the stream. This method is guaranteed not to free the contents + * of the internal buffer, which can still be retrieved. + */ + public void close () + { + } + + /** + * This method flushes all buffered chars to the stream. + */ + public void flush () + { + } + + /** + * This method discards all of the chars that have been written to the + * internal buffer so far by setting the <code>count</code> variable to + * 0. The internal buffer remains at its currently allocated size. + */ + public void reset () + { + synchronized (lock) + { + count = 0; + } + } + + /** + * This method returns the number of chars that have been written to + * the buffer so far. This is the same as the value of the protected + * <code>count</code> variable. If the <code>reset</code> method is + * called, then this value is reset as well. Note that this method does + * not return the length of the internal buffer, but only the number + * of chars that have been written to it. + * + * @return The number of chars in the internal buffer + * + * @see #reset() + */ + public int size () + { + return count; + } + + /** + * This method returns a char array containing the chars that have been + * written to this stream so far. This array is a copy of the valid + * chars in the internal buffer and its length is equal to the number of + * valid chars, not necessarily to the the length of the current + * internal buffer. Note that since this method allocates a new array, + * it should be used with caution when the internal buffer is very large. + */ + public char[] toCharArray () + { + synchronized (lock) + { + char[] nc = new char[count]; + System.arraycopy(buf, 0, nc, 0, count); + return nc; + } + } + + /** + * Returns the chars in the internal array as a <code>String</code>. The + * chars in the buffer are converted to characters using the system default + * encoding. There is an overloaded <code>toString()</code> method that + * allows an application specified character encoding to be used. + * + * @return A <code>String</code> containing the data written to this + * stream so far + */ + public String toString () + { + synchronized (lock) + { + return new String (buf, 0, count); + } + } + + /** + * This method writes the writes the specified char into the internal + * buffer. + * + * @param oneChar The char to be read passed as an int + */ + public void write (int oneChar) + { + synchronized (lock) + { + resize (1); + buf[count++] = (char) oneChar; + } + } + + /** + * This method writes <code>len</code> chars from the passed in array + * <code>buf</code> starting at index <code>offset</code> into that buffer + * + * @param buffer The char array to write data from + * @param offset The index into the buffer to start writing data from + * @param len The number of chars to write + */ + public void write (char[] buffer, int offset, int len) + { + synchronized (lock) + { + if (len >= 0) + resize (len); + System.arraycopy(buffer, offset, buf, count, len); + count += len; + } + } + + /** + * This method writes <code>len</code> chars from the passed in + * <code>String</code> <code>buf</code> starting at index + * <code>offset</code> into the internal buffer. + * + * @param str The <code>String</code> to write data from + * @param offset The index into the string to start writing data from + * @param len The number of chars to write + */ + public void write (String str, int offset, int len) + { + synchronized (lock) + { + if (len >= 0) + resize (len); + str.getChars(offset, offset + len, buf, count); + count += len; + } + } + + /** + * This method writes all the chars that have been written to this stream + * from the internal buffer to the specified <code>Writer</code>. + * + * @param out The <code>Writer</code> to write to + * + * @exception IOException If an error occurs + */ + public void writeTo (Writer out) throws IOException + { + synchronized (lock) + { + out.write(buf, 0, count); + } + } + + /** + * This private method makes the buffer bigger when we run out of room + * by allocating a larger buffer and copying the valid chars from the + * old array into it. This is obviously slow and should be avoided by + * application programmers by setting their initial buffer size big + * enough to hold everything if possible. + */ + private void resize (int len) + { + if (count + len >= buf.length) + { + int newlen = buf.length * 2; + if (count + len > newlen) + newlen = count + len; + char[] newbuf = new char[newlen]; + System.arraycopy(buf, 0, newbuf, 0, count); + buf = newbuf; + } + } + + /** + * The internal buffer where the data written is stored + */ + protected char[] buf; + + /** + * The number of chars that have been written to the buffer + */ + protected int count; +} |