212 lines
6.3 KiB
Java
212 lines
6.3 KiB
Java
/* Writer.java -- Base class for character output streams
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Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.io;
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/* Written using "Java Class Libraries", 2nd edition, plus online
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* API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Believed complete and correct.
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*/
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/**
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* This abstract class forms the base of the hierarchy of classes that
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* write output as a stream of chars. It provides a common set of methods
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* for writing chars to stream. Subclasses implement and/or extend these
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* methods to write chars in a particular manner or to a particular
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* destination such as a file on disk or network connection.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Per Bothner <bothner@cygnus.com>
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*/
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public abstract class Writer
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{
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/*************************************************************************/
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/**
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* This is the object used to synchronize criticial code sections for
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* thread safety. Subclasses should use this field instead of using
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* synchronized methods or explicity synchronizations on <code>this</code>
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*/
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protected Object lock;
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/*************************************************************************/
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/*
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* Constructors
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*/
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/**
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* This is the default no-argument constructor for this class. This method
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* will set up the class to synchronize criticial sections on itself.
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*/
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protected
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Writer()
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{
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lock = this;
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}
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/*************************************************************************/
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/**
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* This method initializes a <code>Writer</code> that will synchronize
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* on the specified <code>Object</code>.
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*
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* @param obj The <code>Object</code> to use for synchronizing critical
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* sections
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*/
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protected
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Writer(Object lock)
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{
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this.lock = lock;
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}
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/*************************************************************************/
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/*
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* Instance Methods
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*/
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/**
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* This method forces any data that may have been buffered to be written
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* to the underlying output device. Please note that the host environment
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* might perform its own buffering unbeknowst to Java. In that case, a
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* write made (for example, to a disk drive) might be cached in OS
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* buffers instead of actually being written to disk.
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*
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* @exception IOException If an error occurs
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*/
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public abstract void
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flush() throws IOException;
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/*************************************************************************/
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/**
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* This method closes the stream. Any internal or native resources associated
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* with this stream are freed. Any subsequent attempt to access the stream
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* might throw an exception.
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* <p>
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* This method in this class does nothing.
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*
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* @exception IOException If an error occurs
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*/
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public abstract void
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close() throws IOException;
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/*************************************************************************/
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/**
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* This method writes a single char to the output stream.
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*
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* @param b The char to be written to the output stream, passed as an int
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*
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* @exception IOException If an error occurs
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*/
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public void
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write(int b) throws IOException
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{
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char[] buf = new char[1];
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buf[0] = (char)b;
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write(buf, 0, buf.length);
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}
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/*************************************************************************/
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/**
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* This method all the writes char from the passed array to the output stream.
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* This method is equivalent to <code>write(buf, 0, buf.length)</code> which
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* is exactly how it is implemented in this class.
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*
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* @param buf The array of char to write
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*
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* @exception IOException If an error occurs
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*/
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public void
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write(char[] buf) throws IOException
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{
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write(buf, 0, buf.length);
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}
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/*************************************************************************/
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/**
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* This method writes <code>len</code> char from the specified array
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* <code>buf</code> starting at index <code>offset</code> into the array.
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* <p>
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* Subclasses must provide an implementation of this abstract method.
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*
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* @param buf The array of char to write from
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* @param offset The index into the array to start writing from
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* @param len The number of char to write
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*
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* @exception IOException If an error occurs
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*/
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public abstract void
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write(char[] buf, int offset, int len) throws IOException;
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/*************************************************************************/
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/**
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* This method writes all the characters in a <code>String</code> to the
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* output.
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*
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* @param str The <code>String</code> whose chars are to be written.
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*
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* @param IOException If an error occurs
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*/
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public void
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write(String str) throws IOException
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{
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write(str, 0, str.length());
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}
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/*************************************************************************/
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/**
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* This method writes <code>len</code> chars from the <code>String</code>
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* starting at position <code>offset</code>.
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*
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* @param str The <code>String</code> that is to be written
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* @param offset The character offset into the <code>String</code> to start
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* writing from
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* @param len The number of chars to write
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*
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* @exception IOException If an error occurs
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*/
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public void
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write(String str, int offset, int len) throws IOException
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{
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// FIXME - for libgcj re-write using native code to not require copied buffer.
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char[] buf = new char[len];
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str.getChars(offset, offset + len, buf, 0);
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write(buf, 0, len);
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}
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} // class Writer
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