1/*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.codemodel.internal.fmt;
27
28import java.io.BufferedReader;
29import java.io.BufferedWriter;
30import java.io.IOException;
31import java.io.InputStream;
32import java.io.InputStreamReader;
33import java.io.OutputStream;
34import java.io.OutputStreamWriter;
35import java.io.PrintWriter;
36import java.text.ParseException;
37import java.util.Iterator;
38import java.util.List;
39
40import com.sun.codemodel.internal.JClass;
41import com.sun.codemodel.internal.JPackage;
42import com.sun.codemodel.internal.JResourceFile;
43import com.sun.codemodel.internal.JTypeVar;
44
45/**
46 * Statically generated Java soruce file.
47 *
48 * <p>
49 * This {@link JResourceFile} implementation will generate a Java source
50 * file by copying the source code from a resource.
51 * <p>
52 * While copying a resource, we look for a package declaration and
53 * replace it with the target package name. This allows the static Java
54 * source code to have an arbitrary package declaration.
55 * <p>
56 * You can also use the getJClass method to obtain a {@link JClass}
57 * object that represents the static file. This allows the client code
58 * to refer to the class from other CodeModel generated code.
59 * <p>
60 * Note that because we don't parse the static Java source code,
61 * the returned {@link JClass} object doesn't respond to methods like
62 * "isInterface" or "_extends",
63 *
64 * @author
65 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
66 */
67public final class JStaticJavaFile extends JResourceFile {
68
69    private final JPackage pkg;
70    private final String className;
71    private final ResourceLoader source;
72    private final JStaticClass clazz;
73    private final LineFilter filter;
74
75    public JStaticJavaFile(JPackage _pkg, String _className, Class<?> loadingClass, LineFilter _filter) {
76        super(_className + ".java");
77        if (loadingClass == null) throw new NullPointerException();
78        this.pkg = _pkg;
79        this.clazz = new JStaticClass();
80        this.className = _className;
81        this.source = new ResourceLoader(_className, loadingClass);
82        this.filter = _filter;
83    }
84
85    /**
86     * Returns a class object that represents a statically generated code.
87     */
88    public final JClass getJClass() {
89        return clazz;
90    }
91
92    protected boolean isResource() {
93        return false;
94    }
95
96    protected  void build(OutputStream os) throws IOException {
97        int lineNumber=1;
98        try (
99                InputStream is = source.getResourceAsStream();
100                BufferedReader r = new BufferedReader(new InputStreamReader(is));
101                PrintWriter w = new PrintWriter(new BufferedWriter(new OutputStreamWriter(os)));
102        ) {
103            LineFilter filter = createLineFilter();
104            String line;
105            while((line=r.readLine())!=null) {
106                line = filter.process(line);
107                if(line!=null)
108                    w.println(line);
109                lineNumber++;
110            }
111        } catch( ParseException e ) {
112            throw new IOException("unable to process "+source+" line:"+lineNumber+"\n"+e.getMessage());
113        }
114    }
115
116    /**
117     * Creates a {@link LineFilter}.
118     * <p>
119     * A derived class can override this method to process
120     * the contents of the source file.
121     */
122    private LineFilter createLineFilter() {
123        // this filter replaces the package declaration.
124        LineFilter f = new LineFilter() {
125            public String process(String line) {
126                if(!line.startsWith("package ")) return line;
127
128                // replace package decl
129                if( pkg.isUnnamed() )
130                    return null;
131                else
132                    return "package "+pkg.name()+";";
133            }
134        };
135        if( filter!=null )
136            return new ChainFilter(filter,f);
137        else
138            return f;
139    }
140
141    /**
142     * Filter that alters the Java source code.
143     * <p>
144     * By implementing this interface, derived classes
145     * can modify the Java source file before it's written out.
146     */
147    public interface LineFilter {
148        /**
149         * @param line
150         *      a non-null valid String that corresponds to one line.
151         *      No '\n' included.
152         * @return
153         *      null to strip the line off. Otherwise the returned
154         *      String will be written out. Do not add '\n' at the end
155         *      of this string.
156         *
157         * @exception ParseException
158         *      when for some reason there's an error in the line.
159         */
160        String process(String line) throws ParseException;
161    }
162
163    /**
164     * A {@link LineFilter} that combines two {@link LineFilter}s.
165     */
166    public final static class ChainFilter implements LineFilter {
167        private final LineFilter first,second;
168        public ChainFilter( LineFilter first, LineFilter second ) {
169            this.first=first;
170            this.second=second;
171        }
172        public String process(String line) throws ParseException {
173            line = first.process(line);
174            if(line==null)  return null;
175            return second.process(line);
176        }
177    }
178
179
180    private class JStaticClass extends JClass {
181
182        private final JTypeVar[] typeParams;
183
184        JStaticClass() {
185            super(pkg.owner());
186            // TODO: allow those to be specified
187            typeParams = new JTypeVar[0];
188        }
189
190        public String name() {
191            return className;
192        }
193
194        public String fullName() {
195            if(pkg.isUnnamed())
196                return className;
197            else
198                return pkg.name()+'.'+className;
199        }
200
201        public JPackage _package() {
202            return pkg;
203        }
204
205        public JClass _extends() {
206            throw new UnsupportedOperationException();
207        }
208
209        public Iterator<JClass> _implements() {
210            throw new UnsupportedOperationException();
211        }
212
213        public boolean isInterface() {
214            throw new UnsupportedOperationException();
215        }
216
217        public boolean isAbstract() {
218            throw new UnsupportedOperationException();
219        }
220
221        public JTypeVar[] typeParams() {
222            return typeParams;
223        }
224
225        protected JClass substituteParams(JTypeVar[] variables, List<JClass> bindings) {
226            return this;
227        }
228    }
229
230    static class ResourceLoader {
231        Class<?> loadingClass;
232        String shortName;
233
234        ResourceLoader(String shortName, Class<?> loadingClass) {
235            this.loadingClass = loadingClass;
236            this.shortName = shortName;
237        }
238
239        InputStream getResourceAsStream() {
240            // some people didn't like our jars to contain files with .java extension,
241            // so when we build jars, we'' use ".java_". But when we run from the workspace,
242            // we want the original source code to be used, so we check both here.
243            // see bug 6211503.
244            InputStream stream = loadingClass.getResourceAsStream(shortName + ".java");
245            if (stream == null) {
246                stream = loadingClass.getResourceAsStream(shortName + ".java_");
247            }
248            if (stream == null) {
249                throw new InternalError("Unable to load source code of " + loadingClass.getName() + " as a resource");
250            }
251            return stream;
252        }
253
254    }
255
256}
257