001/*
002 * Copyright 2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *       https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.batch.item.json.builder;
018
019import org.springframework.batch.item.file.FlatFileFooterCallback;
020import org.springframework.batch.item.file.FlatFileHeaderCallback;
021import org.springframework.batch.item.json.JsonFileItemWriter;
022import org.springframework.batch.item.json.JsonObjectMarshaller;
023import org.springframework.core.io.Resource;
024import org.springframework.util.Assert;
025
026/**
027 * Builder for {@link JsonFileItemWriter}.
028 *
029 * @param <T> type of objects to write as Json output.
030 * @author Mahmoud Ben Hassine
031 * @since 4.1
032 */
033public class JsonFileItemWriterBuilder<T> {
034
035        private Resource resource;
036        private JsonObjectMarshaller<T> jsonObjectMarshaller;
037        private FlatFileHeaderCallback headerCallback;
038        private FlatFileFooterCallback footerCallback;
039
040        private String name;
041        private String encoding = JsonFileItemWriter.DEFAULT_CHARSET;
042        private String lineSeparator = JsonFileItemWriter.DEFAULT_LINE_SEPARATOR;
043
044        private boolean append = false;
045        private boolean forceSync = false;
046        private boolean saveState = true;
047        private boolean shouldDeleteIfExists = true;
048        private boolean shouldDeleteIfEmpty = false;
049        private boolean transactional = JsonFileItemWriter.DEFAULT_TRANSACTIONAL;
050
051        /**
052         * Configure if the state of the {@link org.springframework.batch.item.ItemStreamSupport}
053         * should be persisted within the {@link org.springframework.batch.item.ExecutionContext}
054         * for restart purposes.
055         *
056         * @param saveState defaults to true
057         * @return The current instance of the builder.
058         */
059        public JsonFileItemWriterBuilder<T> saveState(boolean saveState) {
060                this.saveState = saveState;
061
062                return this;
063        }
064
065        /**
066         * The name used to calculate the key within the
067         * {@link org.springframework.batch.item.ExecutionContext}. Required if
068         * {@link #saveState(boolean)} is set to true.
069         *
070         * @param name name of the reader instance
071         * @return The current instance of the builder.
072         * @see org.springframework.batch.item.ItemStreamSupport#setName(String)
073         */
074        public JsonFileItemWriterBuilder<T> name(String name) {
075                this.name = name;
076
077                return this;
078        }
079
080        /**
081         * A flag indicating that changes should be force-synced to disk on flush.  Defaults
082         * to false.
083         *
084         * @param forceSync value to set the flag to
085         * @return The current instance of the builder.
086         * @see JsonFileItemWriter#setForceSync(boolean)
087         */
088        public JsonFileItemWriterBuilder<T> forceSync(boolean forceSync) {
089                this.forceSync = forceSync;
090
091                return this;
092        }
093
094        /**
095         * String used to separate lines in output.  Defaults to the System property
096         * <code>line.separator</code>.
097         *
098         * @param lineSeparator value to use for a line separator
099         * @return The current instance of the builder.
100         * @see JsonFileItemWriter#setLineSeparator(String)
101         */
102        public JsonFileItemWriterBuilder<T> lineSeparator(String lineSeparator) {
103                this.lineSeparator = lineSeparator;
104
105                return this;
106        }
107
108        /**
109         * Set the {@link JsonObjectMarshaller} to use to marshal objects to json.
110         *
111         * @param jsonObjectMarshaller to use
112         * @return The current instance of the builder.
113         * @see JsonFileItemWriter#setJsonObjectMarshaller(JsonObjectMarshaller)
114         */
115        public JsonFileItemWriterBuilder<T> jsonObjectMarshaller(JsonObjectMarshaller<T> jsonObjectMarshaller) {
116                this.jsonObjectMarshaller = jsonObjectMarshaller;
117
118                return this;
119        }
120
121        /**
122         * The {@link Resource} to be used as output.
123         *
124         * @param resource the output of the writer.
125         * @return The current instance of the builder.
126         * @see JsonFileItemWriter#setResource(Resource)
127         */
128        public JsonFileItemWriterBuilder<T> resource(Resource resource) {
129                this.resource = resource;
130
131                return this;
132        }
133
134        /**
135         * Encoding used for output.
136         *
137         * @param encoding encoding type.
138         * @return The current instance of the builder.
139         * @see JsonFileItemWriter#setEncoding(String)
140         */
141        public JsonFileItemWriterBuilder<T> encoding(String encoding) {
142                this.encoding = encoding;
143
144                return this;
145        }
146
147        /**
148         * If set to true, once the step is complete, if the resource previously provided is
149         * empty, it will be deleted.
150         *
151         * @param shouldDelete defaults to false
152         * @return The current instance of the builder
153         * @see JsonFileItemWriter#setShouldDeleteIfEmpty(boolean)
154         */
155        public JsonFileItemWriterBuilder<T> shouldDeleteIfEmpty(boolean shouldDelete) {
156                this.shouldDeleteIfEmpty = shouldDelete;
157
158                return this;
159        }
160
161        /**
162         * If set to true, upon the start of the step, if the resource already exists, it will
163         * be deleted and recreated.
164         *
165         * @param shouldDelete defaults to true
166         * @return The current instance of the builder
167         * @see JsonFileItemWriter#setShouldDeleteIfExists(boolean)
168         */
169        public JsonFileItemWriterBuilder<T> shouldDeleteIfExists(boolean shouldDelete) {
170                this.shouldDeleteIfExists = shouldDelete;
171
172                return this;
173        }
174
175        /**
176         * If set to true and the file exists, the output will be appended to the existing
177         * file.
178         *
179         * @param append defaults to false
180         * @return The current instance of the builder
181         * @see JsonFileItemWriter#setAppendAllowed(boolean)
182         */
183        public JsonFileItemWriterBuilder<T> append(boolean append) {
184                this.append = append;
185
186                return this;
187        }
188
189        /**
190         * A callback for header processing.
191         *
192         * @param callback {@link FlatFileHeaderCallback} implementation
193         * @return The current instance of the builder
194         * @see JsonFileItemWriter#setHeaderCallback(FlatFileHeaderCallback)
195         */
196        public JsonFileItemWriterBuilder<T> headerCallback(FlatFileHeaderCallback callback) {
197                this.headerCallback = callback;
198
199                return this;
200        }
201
202        /**
203         * A callback for footer processing.
204         *
205         * @param callback {@link FlatFileFooterCallback} implementation
206         * @return The current instance of the builder
207         * @see JsonFileItemWriter#setFooterCallback(FlatFileFooterCallback)
208         */
209        public JsonFileItemWriterBuilder<T> footerCallback(FlatFileFooterCallback callback) {
210                this.footerCallback = callback;
211
212                return this;
213        }
214
215        /**
216         * If set to true, the flushing of the buffer is delayed while a transaction is active.
217         *
218         * @param transactional defaults to true
219         * @return The current instance of the builder
220         * @see JsonFileItemWriter#setTransactional(boolean)
221         */
222        public JsonFileItemWriterBuilder<T> transactional(boolean transactional) {
223                this.transactional = transactional;
224
225                return this;
226        }
227
228        /**
229         * Validate the configuration and build a new {@link JsonFileItemWriter}.
230         *
231         * @return a new instance of the {@link JsonFileItemWriter}
232         */
233        public JsonFileItemWriter<T> build() {
234                Assert.notNull(this.resource, "A resource is required.");
235                Assert.notNull(this.jsonObjectMarshaller, "A json object marshaller is required.");
236
237                if (this.saveState) {
238                        Assert.hasText(this.name, "A name is required when saveState is true");
239                }
240
241                JsonFileItemWriter<T> jsonFileItemWriter = new JsonFileItemWriter<>(this.resource, this.jsonObjectMarshaller);
242
243                jsonFileItemWriter.setName(this.name);
244                jsonFileItemWriter.setAppendAllowed(this.append);
245                jsonFileItemWriter.setEncoding(this.encoding);
246                if (this.headerCallback != null) {
247                        jsonFileItemWriter.setHeaderCallback(this.headerCallback);
248                }
249                if (this.footerCallback != null) {
250                        jsonFileItemWriter.setFooterCallback(this.footerCallback);
251                }
252                jsonFileItemWriter.setForceSync(this.forceSync);
253                jsonFileItemWriter.setLineSeparator(this.lineSeparator);
254                jsonFileItemWriter.setSaveState(this.saveState);
255                jsonFileItemWriter.setShouldDeleteIfEmpty(this.shouldDeleteIfEmpty);
256                jsonFileItemWriter.setShouldDeleteIfExists(this.shouldDeleteIfExists);
257                jsonFileItemWriter.setTransactional(this.transactional);
258
259                return jsonFileItemWriter;
260        }
261}