Java example source code file (CodeWriter.java)

This example Java source code file (CodeWriter.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

charsetencoder, codewriter, ioexception, jpackage, outputstreamwriter, override, string, throwable, unicodeescapewriter

The CodeWriter.java Java example source code

/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 * 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 com.sun.codemodel.internal;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.CharsetEncoder;

import com.sun.codemodel.internal.util.EncoderFactory;
import com.sun.codemodel.internal.util.UnicodeEscapeWriter;

/**
 * Receives generated code and writes to the appropriate storage.
 *
 * @author
 *      Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
 */
public abstract class CodeWriter {

    /**
     * Encoding to be used by the writer. Null means platform specific encoding.
     *
     * @since 2.5
     */
    protected String encoding = null;

    /**
     * Called by CodeModel to store the specified file.
     * The callee must allocate a storage to store the specified file.
     *
     * <p>
     * The returned stream will be closed before the next file is
     * stored. So the callee can assume that only one OutputStream
     * is active at any given time.
     *
     * @param   pkg
     *      The package of the file to be written.
     * @param   fileName
     *      File name without the path. Something like
     *      "Foo.java" or "Bar.properties"
     */
    public abstract OutputStream openBinary( JPackage pkg, String fileName ) throws IOException;

    /**
     * Called by CodeModel to store the specified file.
     * The callee must allocate a storage to store the specified file.
     *
     * <p>
     * The returned stream will be closed before the next file is
     * stored. So the callee can assume that only one OutputStream
     * is active at any given time.
     *
     * @param   pkg
     *      The package of the file to be written.
     * @param   fileName
     *      File name without the path. Something like
     *      "Foo.java" or "Bar.properties"
     */
    public Writer openSource( JPackage pkg, String fileName ) throws IOException {
        final OutputStreamWriter bw = encoding != null
                ? new OutputStreamWriter(openBinary(pkg,fileName), encoding)
                : new OutputStreamWriter(openBinary(pkg,fileName));

        // create writer
        try {
            return new UnicodeEscapeWriter(bw) {
                // can't change this signature to Encoder because
                // we can't have Encoder in method signature
                private final CharsetEncoder encoder = EncoderFactory.createEncoder(bw.getEncoding());
                @Override
                protected boolean requireEscaping(int ch) {
                    // control characters
                    if( ch<0x20 && " \t\r\n".indexOf(ch)==-1 )  return true;
                    // check ASCII chars, for better performance
                    if( ch<0x80 )       return false;

                    return !encoder.canEncode((char)ch);
                }
            };
        } catch( Throwable t ) {
            return new UnicodeEscapeWriter(bw);
        }
    }

    /**
     * Called by CodeModel at the end of the process.
     */
    public abstract void close() throws IOException;
}