UsageException.java

/*
 * Copyright 2011 the original author or authors.
 *
 * Licensed 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 com.trigonic.utils.spring.cmdline;

import static java.lang.System.err;

import java.io.IOException;

import joptsimple.OptionParser;

public class UsageException extends RuntimeException {
    private static final long serialVersionUID = 1L;
    
    private final OptionParser parser;
    private final CommandLineMetaData metaData;

    public UsageException(OptionParser parser, CommandLineMetaData metaData, Exception cause) {
        super(cause);
        this.parser = parser;
        this.metaData = metaData;
    }
    
    public String getMessage() {
        Throwable cause = getCause();
        return cause == null ? null : cause.getMessage();
    }

    public void printUsage() {
        String message = getMessage();
        if (message != null) {
            err.print("Error: ");
            err.println(getCause().getMessage());
        }
        
        err.println();

        try {
            parser.printHelpOn(err);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        
        metaData.printOperandsOn(err);
    }
}