ResponseUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.solmix.api.request;

import java.io.IOException;
import java.io.Writer;

/**
 * Response-related utilities
 * 
 * @since 2.1
 */
public class ResponseUtil
{

    private static class XmlEscapingWriter extends Writer
    {

        private final Writer target;

        XmlEscapingWriter(Writer target)
        {
            this.target = target;
        }

        @Override
        public void close() throws IOException {
            target.close();
        }

        @Override
        public void flush() throws IOException {
            target.flush();
        }

        @Override
        public void write(char[] buffer, int offset, int length) throws IOException {
            for (int i = offset; i < offset + length; i++) {
                write(buffer[i]);
            }
        }

        @Override
        public void write(char[] cbuf) throws IOException {
            write(cbuf, 0, cbuf.length);
        }

        @Override
        public void write(int c) throws IOException {
            if (c == '&') {
                target.write("&");
            } else if (c == '<') {
                target.write("<");
            } else if (c == '>') {
                target.write(">");
            } else {
                target.write(c);
            }
        }

        @Override
        public void write(String str, int off, int len) throws IOException {
            write(str.toCharArray(), off, len);
        }

        @Override
        public void write(String str) throws IOException {
            write(str.toCharArray());
        }
    }

    /** Escape xml text */
    public static String escapeXml(String input) {
        if (input == null) {
            return null;
        }

        final StringBuilder b = new StringBuilder(input.length());
        for (int i = 0; i < input.length(); i++) {
            final char c = input.charAt(i);
            if (c == '&') {
                b.append("&");
            } else if (c == '<') {
                b.append("<");
            } else if (c == '>') {
                b.append(">");
            } else {
                b.append(c);
            }
        }
        return b.toString();
    }

    /**
     * Return a Writer that writes escaped XML text to target
     */
    public static Writer getXmlEscapingWriter(Writer target) {
        return new XmlEscapingWriter(target);
    }
}