samples/connectors/src/main/java/org/apache/edgent/samples/connectors/Options.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.apache.edgent.samples.connectors;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.apache.edgent.function.Function;

/**
 * Simple command option processor.
 */
public class Options {
    private static final Map<String,Function<String,?>> handlers = new HashMap<>();
    private static final Map<String,Object> options = new HashMap<>();
    private static final Map<String,Object> defaults = new HashMap<>();
    
    public <T> void addHandler(String opt, Function<String,T> cvtFn) {
        addHandler(opt, cvtFn, null);
    }
    
    public <T> void addHandler(String opt, Function<String,T> cvtFn, T dflt) {
        handlers.put(opt, cvtFn);
        if (dflt != null)
            defaults.put(opt, dflt);
    }
    
    public void processArgs(String[] args) {
        for (Map.Entry<String,Function<String,?>> e : handlers.entrySet()) {
            handleOpt(e.getKey(), e.getValue(), args);
        }

        for (String arg : args) {
            String[] item = arg.split("=");
            if (!handlers.containsKey(item[0]))
                throw new IllegalArgumentException("Unrecognized argument '"+arg+"'");
        }
    }
    
    private void handleOpt(String opt, Function<String,?> cvtFn, String[] args) {
        String v = getArg(cvtFn!=null ? opt : opt+"=true", args);
        if (v != null)
            options.put(opt, cvtFn==null ? true : cvtFn.apply(v));
        else if (defaults.get(opt) != null)
            options.put(opt, defaults.get(opt));
    }

    public <T> T get(String opt) {
        return get(opt, null);
    }
    
    @SuppressWarnings("unchecked")
    public <T> T get(String opt, T dflt) {
        return options.get(opt) == null ? dflt : (T)options.get(opt); 
    }
    
    public Set<Map.Entry<String,Object>> getAll() {
        return Collections.unmodifiableSet(options.entrySet());
    }
    
    public void put(String opt, Object value) {
        options.put(opt, value);
    }
    
    private String getArg(String item, String[] args) {
        String[] itemParts = item.split("=");
        if (itemParts.length>1)
            item = itemParts[0];
        for (String arg : args) {
            String[] parts = arg.split("=");
            if (item.equals(parts[0])) {
                if (parts.length > 1)
                    return parts[1];
                else
                    return itemParts.length > 1 ? itemParts[1] : parts[1];
            }
        }
        return null;
    }
}