001 /*
002 $Id: ReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $
003
004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005
006 Redistribution and use of this software and associated documentation
007 ("Software"), with or without modification, are permitted provided
008 that the following conditions are met:
009
010 1. Redistributions of source code must retain copyright
011 statements and notices. Redistributions must also contain a
012 copy of this document.
013
014 2. Redistributions in binary form must reproduce the
015 above copyright notice, this list of conditions and the
016 following disclaimer in the documentation and/or other
017 materials provided with the distribution.
018
019 3. The name "groovy" must not be used to endorse or promote
020 products derived from this Software without prior written
021 permission of The Codehaus. For written permission,
022 please contact info@codehaus.org.
023
024 4. Products derived from this Software may not be called "groovy"
025 nor may "groovy" appear in their names without prior written
026 permission of The Codehaus. "groovy" is a registered
027 trademark of The Codehaus.
028
029 5. Due credit should be given to The Codehaus -
030 http://groovy.codehaus.org/
031
032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043 OF THE POSSIBILITY OF SUCH DAMAGE.
044
045 */
046
047 package org.codehaus.groovy.control.io;
048
049 import java.io.IOException;
050 import java.io.Reader;
051
052 import org.codehaus.groovy.control.HasCleanup;
053 import org.codehaus.groovy.control.Janitor;
054
055
056 /**
057 * An interface for things that can supply (and resupply) a Reader
058 * on a source stream.
059 *
060 * @author <a href="mailto:cpoirier@dreaming.org">Chris Poirier</a>
061 *
062 * @version $Id: ReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $
063 */
064
065 public interface ReaderSource extends HasCleanup
066 {
067
068 /**
069 * Returns a new Reader on the underlying source object. Returns
070 * null if the source can't be reopened.
071 */
072
073 Reader getReader() throws IOException;
074
075
076
077 /**
078 * Returns true if the source can be restarted (ie. if getReader()
079 * will return non-null on subsequent calls.
080 */
081
082 boolean canReopenSource();
083
084
085
086 /**
087 * Returns a line from the source, or null, if unavailable. If
088 * you supply a Janitor, resources will be cached.
089 */
090
091 String getLine( int lineNumber, Janitor janitor );
092
093
094
095 /**
096 * Cleans up any cached resources used by getLine().
097 */
098
099 void cleanup();
100
101 }