1 /*
2  * Copyright (C) 2017 The Dagger Authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package dagger.internal.codegen;
18 
19 import static com.google.common.base.Preconditions.checkArgument;
20 
21 import com.google.common.collect.ImmutableList;
22 import com.google.testing.compile.JavaFileObjects;
23 import java.util.Collections;
24 import java.util.HashSet;
25 import java.util.Set;
26 import javax.tools.JavaFileObject;
27 
28 /**
29  * A fluent API to build a {@link JavaFileObject} appropriate for a current set of settings, such as
30  * compiler mode.
31  *
32  * <p>After creating a builder, you can add lines to the file. Call {@link #addLines(String...)} to
33  * add lines irrespective of the settings. If you want to add different lines for different possible
34  * settings, call {@link #addLinesIf(Object, String...)} to add those lines only if the given
35  * setting has been added via {@link #withSetting(Object)} or {@link #withSettings(Object...)}.
36  */
37 final class JavaFileBuilder {
38   private final String qualifiedName;
39   private final Set<Object> settings = new HashSet<>();
40 
41   private final ImmutableList.Builder<String> sourceLines = ImmutableList.builder();
42 
43   /** Creates a builder for a file whose top level type has a given qualified name. */
JavaFileBuilder(String qualifiedName)44   JavaFileBuilder(String qualifiedName) {
45     checkArgument(!qualifiedName.isEmpty());
46     this.qualifiedName = qualifiedName;
47   }
48 
49   // TODO(cgdecker): Get rid of the special constructor/method for CompilerMode
50 
51   /** Creates a builder for a file whose top level type has a given qualified name. */
JavaFileBuilder(CompilerMode compilerMode, String qualifiedName)52   JavaFileBuilder(CompilerMode compilerMode, String qualifiedName) {
53     this(qualifiedName);
54     settings.add(compilerMode);
55   }
56 
57   /** Adds the given setting as one that code should be generated for. */
withSetting(Object setting)58   JavaFileBuilder withSetting(Object setting) {
59     this.settings.add(setting);
60     return this;
61   }
62 
63   /** Adds the given settings as one that code should be generated for. */
withSettings(Object s1, Object s2, Object... more)64   JavaFileBuilder withSettings(Object s1, Object s2, Object... more) {
65     settings.add(s1);
66     settings.add(s2);
67     Collections.addAll(settings, more);
68     return this;
69   }
70 
71   /** Adds lines no matter what the {@link CompilerMode} is. */
addLines(String... lines)72   JavaFileBuilder addLines(String... lines) {
73     sourceLines.add(lines);
74     return this;
75   }
76 
77   /** Adds lines if in the given mode. */
addLinesIn(CompilerMode mode, String... lines)78   JavaFileBuilder addLinesIn(CompilerMode mode, String... lines) {
79     return addLinesIf(mode, lines);
80   }
81 
82   /** Adds lines if in the given setting is set. */
addLinesIf(Object setting, String... lines)83   JavaFileBuilder addLinesIf(Object setting, String... lines) {
84     if (settings.contains(setting)) {
85       sourceLines.add(lines);
86     }
87     return this;
88   }
89 
90   /** Builds the {@link JavaFileObject}. */
build()91   JavaFileObject build() {
92     return JavaFileObjects.forSourceLines(qualifiedName, sourceLines.build());
93   }
94 }
95