org.eclipse.sisu.plexus/src/org/eclipse/sisu/plexus/PlexusDateTypeConverter.java

/*******************************************************************************
 * Copyright (c) 2010-present Sonatype, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Stuart McCulloch (Sonatype, Inc.) - initial API and implementation
 *******************************************************************************/
package org.eclipse.sisu.plexus;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import com.google.inject.Binder;
import com.google.inject.Module;
import com.google.inject.TypeLiteral;
import com.google.inject.matcher.AbstractMatcher;
import com.google.inject.spi.TypeConverter;

/**
 * {@link TypeConverter} {@link Module} that converts Plexus formatted date strings into {@link Date}s.
 */
public final class PlexusDateTypeConverter
    extends AbstractMatcher<TypeLiteral<?>>
    implements TypeConverter, Module
{
    // ----------------------------------------------------------------------
    // Constants
    // ----------------------------------------------------------------------

    private static final DateFormat[] PLEXUS_DATE_FORMATS =
        { new SimpleDateFormat( "yyyy-MM-dd hh:mm:ss.S a", Locale.US ),
            new SimpleDateFormat( "yyyy-MM-dd hh:mm:ssa", Locale.US ),
            new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss.S", Locale.US ),
            new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss", Locale.US ) };

    private static final String CONVERSION_ERROR = "Cannot convert: \"%s\" to: %s";

    static
    {
        for ( final DateFormat f : PLEXUS_DATE_FORMATS )
        {
            f.setLenient( false ); // turn off lenient parsing as it gives odd results
        }
    }

    // ----------------------------------------------------------------------
    // Public methods
    // ----------------------------------------------------------------------

    public void configure( final Binder binder )
    {
        // we're both matcher and converter
        binder.convertToTypes( this, this );
    }

    public boolean matches( final TypeLiteral<?> type )
    {
        return Date.class == type.getRawType();
    }

    public Object convert( final String value, final TypeLiteral<?> toType )
    {
        for ( final DateFormat f : PLEXUS_DATE_FORMATS )
        {
            try
            {
                synchronized ( f ) // formats are not thread-safe!
                {
                    return f.parse( value );
                }
            }
            catch ( final ParseException e )
            {
                continue; // try another format
            }
        }
        throw new IllegalArgumentException( String.format( CONVERSION_ERROR, value, Date.class ) );
    }
}