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A generic command shell with a client and server part.
/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see options = new HashMap<>();
private final List arguments = new ArrayList<>();
/**
* @param server the server used to find apps.
* @param line the line from the client to interpret.
* @throws Exception if there's something wrong with the line.
*/
public AppCommandParser( AppShellServer server, String line )
throws Exception
{
this.server = server;
this.line = line;
String trimmedLine = line != null ? prepareLine( line ) : line;
this.parse( trimmedLine );
}
private String prepareLine( String line )
{
// Replace \n with space, and remove comments
line = line.trim();
String[] lines = line.split( "\n" );
StringBuilder builder = new StringBuilder();
for ( String singleLine : lines )
{
if ( singleLine.startsWith( "//" ) )
{
continue; // Skip comments
}
if ( builder.length() > 0 )
{
builder.append( ' ' );
}
builder.append( singleLine );
}
return builder.toString();
}
private void parse( String line ) throws Exception
{
if ( line == null || line.trim().length() == 0 )
{
app = new NoopApp();
return;
}
this.parseApp( line );
this.parseParameters( line );
}
/**
* Extracts the app name (f.ex. ls or rm) from the supplied line.
*
* @param line the line to extract the app name from.
* @return the app name for {@code line}.
*/
public static String parseOutAppName( String line )
{
int index = findNextWhiteSpaceOrLeftParenthesis( line, 0 );
return index == -1 ? line : line.substring( 0, index );
}
private void parseApp( String line ) throws Exception
{
int index = findNextWhiteSpaceOrLeftParenthesis( line, 0 );
appName = index == -1 ? line : line.substring( 0, index );
appName = appName.toLowerCase();
app = server.findApp( appName );
if ( app == null )
{
throw new ShellException( "Unknown command '" + appName + "'" );
}
}
private void parseParameters( String line ) throws ShellException
{
String rest = line.substring( appName.length() ).trim();
String[] parsed = tokenizeStringWithQuotes( rest, false );
for ( int i = 0; i < parsed.length; i++ )
{
String string = parsed[i];
if ( app.takesOptions() && isMultiCharOption( string ) )
{
String name = string.substring( 2 );
i = fetchArguments( parsed, i, name );
}
else if ( app.takesOptions() && isSingleCharOption( string ) )
{
String options = string.substring( 1 );
for ( int o = 0; o < options.length(); o++ )
{
String name = String.valueOf( options.charAt( o ) );
i = fetchArguments( parsed, i, name );
}
}
else if ( string.length() > 0 )
{
this.arguments.add( string );
}
}
}
private boolean isOption( String string )
{
return isSingleCharOption( string ) || isMultiCharOption( string );
}
private boolean isMultiCharOption( String string )
{
return string.startsWith( "--" );
}
private boolean isSingleCharOption( String string )
{
return string.startsWith( "-" ) && !isANegativeNumber( string );
}
private boolean isANegativeNumber( String string )
{
try
{
Integer.parseInt( string );
return true;
}
catch ( NumberFormatException e )
{
return false;
}
}
private int fetchArguments( String[] parsed, int whereAreWe, String optionName ) throws ShellException
{
String value = null;
OptionDefinition definition =
this.app.getOptionDefinition( optionName );
if ( definition == null )
{
throw new ShellException( "Unrecognized option '" + optionName + "'" );
}
OptionValueType type = definition.getType();
if ( type == OptionValueType.MUST )
{
whereAreWe++;
String message = "Value required for '" + optionName + "'";
this.assertHasIndex( parsed, whereAreWe, message );
value = parsed[whereAreWe];
if ( this.isOption( value ) )
{
throw new ShellException( message );
}
}
else if ( type == OptionValueType.MAY )
{
if ( this.hasIndex( parsed, whereAreWe + 1 ) &&
!this.isOption( parsed[whereAreWe + 1] ) )
{
whereAreWe++;
value = parsed[whereAreWe];
}
}
this.options.put( optionName, value );
return whereAreWe;
}
private boolean hasIndex( String[] array, int index )
{
return index >= 0 && index < array.length;
}
private void assertHasIndex( String[] array, int index, String message ) throws ShellException
{
if ( !this.hasIndex( array, index ) )
{
throw new ShellException( message );
}
}
private static int findNextWhiteSpaceOrLeftParenthesis( String line, int fromIndex )
{
int indexOfWhiteSpace = line.indexOf( ' ', fromIndex );
if (indexOfWhiteSpace == - 1)
{
indexOfWhiteSpace = line.indexOf( '\t', fromIndex );
}
//allow using both create () and create()
int indexOfLeftParenthesis = line.indexOf( '(', fromIndex );
if (indexOfLeftParenthesis != -1)
{
return Math.min(indexOfWhiteSpace, indexOfLeftParenthesis);
}
else
{
return indexOfWhiteSpace;
}
}
/** @return the name of the app (from {@link #getLine()}). */
public String getAppName()
{
return this.appName;
}
/** @return the app corresponding to the {@link #getAppName()}. */
public App app()
{
return this.app;
}
/** @return the supplied options (from {@link #getLine()}). */
public Map options()
{
return this.options;
}
public String option( String name, String defaultValue )
{
String result = options.get( name );
return result != null ? result : defaultValue;
}
public Number optionAsNumber( String name, Number defaultValue )
{
String value = option( name, null );
if ( value != null )
{
if ( value.indexOf( ',' ) != -1 || value.indexOf( '.' ) != -1 )
{
return Double.valueOf( value );
}
else
{
return Integer.valueOf( value );
}
}
return defaultValue;
}
/** @return the arguments (from {@link #getLine()}). */
public List arguments()
{
return this.arguments;
}
public String argumentWithDefault( int index, String defaultValue )
{
return index < arguments.size() ? arguments.get( index ) : defaultValue;
}
public String argument( int index, String errorMessageIfItDoesNotExist ) throws ShellException
{
if ( index >= arguments.size() )
{
throw new ShellException( errorMessageIfItDoesNotExist );
}
return arguments.get( index );
}
/** @return the entire line from the client. */
public String getLine()
{
return this.line;
}
/** @return the line w/o the app (just the options and arguments). */
public String getLineWithoutApp()
{
return this.line.substring( this.appName.length() ).trim();
}
}
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