/*
 * 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.apache.log4j.helpers;

import java.io.Writer;
import java.io.FilterWriter;
import org.apache.log4j.spi.ErrorHandler;
import org.apache.log4j.spi.ErrorCode;

/**
 * QuietWriter does not throw exceptions when things go wrong. Instead, it
 * delegates error handling to its {@link ErrorHandler}.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * 
 * @since 0.7.3
 */
public class QuietWriter extends FilterWriter {

    protected ErrorHandler errorHandler;

    public QuietWriter(Writer writer, ErrorHandler errorHandler) {
	super(writer);
	setErrorHandler(errorHandler);
    }

    public void write(String string) {
	if (string != null) {
	    try {
		out.write(string);
	    } catch (Exception e) {
		errorHandler.error("Failed to write [" + string + "].", e, ErrorCode.WRITE_FAILURE);
	    }
	}
    }

    public void flush() {
	try {
	    out.flush();
	} catch (Exception e) {
	    errorHandler.error("Failed to flush writer,", e, ErrorCode.FLUSH_FAILURE);
	}
    }

    public void setErrorHandler(ErrorHandler eh) {
	if (eh == null) {
	    // This is a programming error on the part of the enclosing appender.
	    throw new IllegalArgumentException("Attempted to set null ErrorHandler.");
	} else {
	    this.errorHandler = eh;
	}
    }
}
