net.maizegenetics.util.ArgsEngine Maven / Gradle / Ivy
/*
* Args - A Reusable Solution for Command Line Arguments Parsing in Java
*
* Copyright 2008 Adarsh Ramamurthy
*
* 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.
*
* Web site: http://www.adarshr.com/papers/args
*/
package net.maizegenetics.util;
import java.util.HashMap;
import java.util.Map;
/**
* A reusable solution for Command Line Arguments Parsing in Java.
*
* The following shows how to use this API.
*
*
* // Initiate the arguments engine.
* ArgsEngine engine = new ArgsEngine();
*
* // Configure the switches/options. Use true for valued options
* engine.add("-q", "--quiet");
* engine.add("-o", "--redirect-output", true);
* engine.add("-h", "--help");
*
* // Perform the parsing.
* engine.parse(args);
*
* // Start fetching states of switches
* boolean quiet = engine.getBoolean("-q");
*
* if(engine.getBoolean("-o"))
* {
* // For valued options, use getString.
* String redir = engine.getString("-o");
* }
*
*
* This has been modified from the original.
*
* @author Adarsh Ramamurthy
*
* @version 1.0, 12th May 2008
*/
public class ArgsEngine {
/**
* Holds all options configured.
*/
private Map options = new HashMap();
/**
* Indicates if the parse method has been called.
*/
private boolean parseCalled = false;
/**
* Configures the engine by adding options.
*
* @param shortForm the short form of an option. Example: "-h".
*
* @param longForm the long form of an option. Example: "--help".
*/
public void add(String shortForm, String longForm) {
this.add(shortForm, longForm, false);
}
/**
* Configures the engine by adding options.
*
* @param shortForm the short form of an option. Example: "-h".
*
* @param longForm the long form of an option. Example: "--help".
*
* @param valued indicates if the option expects a value. The next argument
* will be considered as the value for this option.
*/
public void add(String shortForm, String longForm, boolean valued) {
Option option = new Option(shortForm, longForm, valued);
this.options.put(shortForm, option);
this.options.put(longForm, option);
}
/**
* Parses the input command line arguments. The result of parsing will
* be stored in the current instance of ArgsEngine.
* Operations {@link #getBoolean(String)}, {@link #getNonOptions()}
* and {@link #getString(String)} can be then used to extract the values.
*
* @param args the command line arguments.
*/
public void parse(String[] args) {
this.parseCalled = true;
for (int i = 0; i < args.length; i++) {
String arg = args[i];
// An option.
if ((arg.startsWith("--") || arg.startsWith("-"))
&& this.options.containsKey(arg)) {
Option option = this.options.get(arg);
if (option.isValued()) {
// This is the last arg.
if (i + 1 >= args.length) {
throw new RuntimeException("Value required for option "
+ arg);
}
option.setValue(args[++i]);
} else {
option.setValue("not-null");
}
} else {
throw new RuntimeException("Unrecognized option " + arg);
}
}
}
/**
* Gets the value for a valued option.
*
* @param key the valued option key. Either short form or long form
* can be input.
*
* @return the value for the option if it's valued, null
* otherwise.
*/
public String getString(String key) {
if (!this.parseCalled) {
throw new IllegalStateException("Method parse not invoked");
}
Option option = this.options.get(key);
// If option is non null and valued, return the value, null otherwise.
return option != null
? (option.isValued() ? option.getValue() : null) : null;
}
/**
* Gets the option.
*
* @param key the option's short form or long form name.
*
* @return true if the option is found in the args parsed,
* false otherwise.
*/
public boolean getBoolean(String key) {
if (!this.parseCalled) {
throw new IllegalStateException("Method parse not invoked");
}
Option option = this.options.get(key);
return option != null ? option.getValue() != null : false;
}
/**
* An object for representing and manipulating with the options.
*
* This class is internal to the ArgsEngine.
*
* @author Adarsh Ramamurthy
*
* @version 1.0, 12th April 2008
*/
private static class Option {
/**
* Short form of the option.
*/
private String shortForm;
/**
* Long form of the option.
*/
private String longForm;
/**
* Indicates if the option is valued.
*/
private boolean valued;
/**
* The value of a valued option.
*/
private String value;
/**
* Constructs an instance of Option taking the short and
* long forms provided.
*
* @param shortForm the short form.
*
* @param longForm the long form.
*/
public Option(String shortForm, String longForm) {
this.shortForm = shortForm;
this.longForm = longForm;
}
/**
* Constructs an instance of Option taking the short and
* long forms provided.
*
* @param shortForm the short form.
*
* @param longForm the long form.
*/
public Option(String shortForm, String longForm, boolean valued) {
this.shortForm = shortForm;
this.longForm = longForm;
this.valued = valued;
}
/**
* Gets the short form name.
*
* @return the short form name.
*/
public String getShortForm() {
return this.shortForm;
}
/**
* Gets the long form name.
*
* @return the long form name.
*/
public String getLongForm() {
return this.longForm;
}
/**
* Tells if the option is valued.
*
* @return true if valued, false otherwise.
*/
public boolean isValued() {
return this.valued;
}
/**
* Gets the value.
*
* @return the value.
*/
public String getValue() {
return this.value;
}
/**
* Sets the value.
*
* @param value the value to set.
*/
public void setValue(String value) {
this.value = value;
}
}
}