001: /*
002: $Id: AbstractReaderSource.java 2361 2005-06-19 15:41:38Z cstein $
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.BufferedReader;
050: import java.io.IOException;
051:
052: import org.codehaus.groovy.control.CompilerConfiguration;
053: import org.codehaus.groovy.control.Janitor;
054:
055: /**
056: * For ReaderSources that can choose a parent class, a base that
057: * provides common functionality.
058: *
059: * @author <a href="mailto:cpoirier@dreaming.org">Chris Poirier</a>
060: *
061: * @version $Id: AbstractReaderSource.java 2361 2005-06-19 15:41:38Z cstein $
062: */
063:
064: public abstract class AbstractReaderSource implements ReaderSource {
065: protected CompilerConfiguration configuration; // Configuration data
066:
067: /**
068: * Standard construction stuff.
069: */
070:
071: public AbstractReaderSource(CompilerConfiguration configuration) {
072: if (configuration == null) {
073: throw new IllegalArgumentException(
074: "Compiler configuration must not be null!");
075: // ... or more relaxed?
076: // configuration = CompilerConfiguration.DEFAULT;
077: }
078: this .configuration = configuration;
079: }
080:
081: /**
082: * Returns true if the source can be restarted (ie. if getReader()
083: * will return non-null on subsequent calls.
084: */
085:
086: public boolean canReopenSource() {
087: return true;
088: }
089:
090: //---------------------------------------------------------------------------
091: // LINE SUPPLY
092:
093: private BufferedReader lineSource = null; // If set, a reader on the current source file
094: private String line = null; // The last line read from the current source file
095: private int number = 0; // The last line number read
096:
097: /**
098: * Returns a line from the source, or null, if unavailable. If
099: * you supply a Janitor, resources will be cached.
100: */
101:
102: public String getLine(int lineNumber, Janitor janitor) {
103: //
104: // If the source is already open and is passed the line we
105: // want, close it.
106:
107: if (lineSource != null && number > lineNumber) {
108: cleanup();
109: }
110:
111: //
112: // If the line source is closed, try to open it.
113:
114: if (lineSource == null) {
115: try {
116: lineSource = new BufferedReader(getReader());
117: } catch (Exception e) {
118: }
119: number = 0;
120: }
121:
122: //
123: // Read until the appropriate line number.
124:
125: if (lineSource != null) {
126: while (number < lineNumber) {
127: try {
128: line = lineSource.readLine();
129: number++;
130: } catch (IOException e) {
131: cleanup();
132: }
133: }
134:
135: if (janitor == null) {
136: cleanup();
137: } else {
138: janitor.register(this );
139: }
140: }
141:
142: return line;
143: }
144:
145: /**
146: * Cleans up any cached resources used by getLine().
147: */
148:
149: public void cleanup() {
150: if (lineSource != null) {
151: try {
152: lineSource.close();
153: } catch (Exception e) {
154: }
155: }
156:
157: lineSource = null;
158: line = null;
159: number = 0;
160: }
161:
162: }
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