Introduce jsonmerge-cli (#24)

* Introduce jsonmerge-cli

* Fix issue with Java 8

* Additional JUnits

* Add Maven Shade plugin for uber JAR creation

* Apply naming standard, exclude json-smart from uber jar

jsonmerge-cli/.gitignore

@@ -0,0 +1 @@
+/target/

jsonmerge-cli/pom.xml

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+<!--
+  Copyright 2022 obvj.net
+  
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+  
+      http://www.apache.org/licenses/LICENSE-2.0
+  
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+ -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>net.obvj</groupId>
+        <artifactId>jsonmerge</artifactId>
+        <version>1.1.1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>jsonmerge-cli</artifactId>
+    <name>JSON Merge CLI</name>
+    <description>
+        CLI tool for merging JSON files
+    </description>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>net.obvj</groupId>
+            <artifactId>jsonmerge-core</artifactId>
+            <version>${project.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>net.minidev</groupId>
+                    <artifactId>json-smart</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>info.picocli</groupId>
+            <artifactId>picocli</artifactId>
+            <version>4.6.3</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <version>${slf4j.version}</version>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.4.0</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <transformers>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <manifestEntries>
+                                        <Main-Class>net.obvj.jsonmerge.cli.Main</Main-Class>
+                                        <X-Compile-Source-JDK>${maven.compile.source}</X-Compile-Source-JDK>
+                                        <X-Compile-Target-JDK>${maven.compile.target}</X-Compile-Target-JDK>
+                                        <Application-Version>${project.version}</Application-Version>
+                                    </manifestEntries>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

jsonmerge-cli/src/main/java/net/obvj/jsonmerge/cli/ApplicationManifest.java

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+/*
+ * Copyright 2022 obvj.net
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.obvj.jsonmerge.cli;
+
+import java.io.InputStream;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+
+/**
+ * A class that holds application information retrieved from the {@code MANIFEST.MF} file.
+ *
+ * @author oswaldo.bapvic.jr
+ * @since 1.2.0
+ */
+public class ApplicationManifest
+{
+    /**
+     * The application name; a string in the format {@code <artifactId>-<version>.jar}
+     */
+    public static final String COMMAND_NAME = parseCommandName(loadManifest());
+
+    private static Manifest loadManifest()
+    {
+        return loadManifest("META-INF/MANIFEST.MF");
+    }
+
+    /**
+     * Loads a {@link Manifest} from the specified file name, or an "empty" object if the
+     * specified file name is not found or not accessible.
+     *
+     * @param fileName the manifest file name to be loaded
+     * @return a {@link Manifest} from the specified file name
+     */
+    static Manifest loadManifest(String fileName)
+    {
+        try (InputStream input = ApplicationManifest.class.getClassLoader()
+                .getResourceAsStream(fileName))
+        {
+            return new Manifest(input);
+        }
+        catch (Exception exception)
+        {
+            return new Manifest();
+        }
+    }
+
+    static String parseCommandName(Manifest manifest)
+    {
+        return String.format("jsonmerge-cli-%s.jar",
+                defaultIfNull(manifest.getMainAttributes(), "Application-Version", "<version>"));
+    }
+
+    private static String defaultIfNull(Attributes attributes, String key, String defaultValue)
+    {
+        String value = attributes.getValue(key);
+        return value != null ? value : defaultValue;
+    }
+
+    private ApplicationManifest()
+    {
+        throw new UnsupportedOperationException("Instantiation not allowed");
+    }
+
+}

jsonmerge-cli/src/main/java/net/obvj/jsonmerge/cli/Main.java

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+/*
+ * Copyright 2022 obvj.net
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.obvj.jsonmerge.cli;
+
+import static net.obvj.jsonmerge.cli.ApplicationManifest.*;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.Callable;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+
+import net.obvj.jsonmerge.JsonMergeOption;
+import net.obvj.jsonmerge.JsonMerger;
+import net.obvj.jsonmerge.provider.JsonProvider;
+import net.obvj.jsonmerge.provider.JsonProviderFactory;
+import picocli.CommandLine;
+import picocli.CommandLine.Command;
+import picocli.CommandLine.Option;
+import picocli.CommandLine.Parameters;
+
+/**
+ * A command line tool to merge JSON files.
+ * <p>
+ * Usage:
+ *
+ * <pre>
+ * {@code Main [-hp] -t <target> [-d <exp=key>]... <FILE1> <FILE2>}
+ * </pre>
+ *
+ * @author oswaldo.bapvic.jr
+ * @since 1.2.0
+ */
+@Command(separator = " ",
+         usageHelpWidth = 90,
+         parameterListHeading = "\nParameters:\n\n",
+         optionListHeading = "\nOptions:\n\n")
+public class Main implements Callable<Integer>
+{
+
+    @Parameters(index = "0",
+            paramLabel = "<FILE1>",
+            description = "The first file to merge")
+    private Path file1;
+
+    @Parameters(index = "1",
+            paramLabel = "<FILE2>",
+            description = "The second file to merge")
+    private Path file2;
+
+    @Option(names = { "-t", "--target" },
+            description = "The target file name (default: result.json)",
+            defaultValue = "result.json",
+            required = true)
+    private Path target;
+
+    @Option(names = { "-d", "--distinct" },
+            paramLabel = "<exp=key>",
+            description = { "Defines one or more distinct keys inside a child path",
+                    "For example: -d $.agents=name",
+                    "             -d $.files=id,version" })
+    private Map<String, String> distinctKeys = Collections.emptyMap();
+
+    @Option(names = { "-p", "--pretty" },
+            description = "Generates a well-formatted result file")
+    private boolean prettyPrinting = false;
+
+    @Option(names = { "-h", "--help" },
+            usageHelp = true,
+            description = "Displays a help message")
+    private boolean helpRequested = false;
+
+    private JsonProvider<JsonObject> provider = JsonProviderFactory.instance()
+            .getByType(JsonObject.class);
+
+    private GsonBuilder gsonBuilder = new GsonBuilder();
+
+    private Logger log = LoggerFactory.getLogger(Main.class);
+
+    /**
+     * Executes the CLI logic.
+     *
+     * @return the exit code to be handled by the CLI framework
+     */
+    @Override
+    public Integer call() throws Exception
+    {
+        String result = parseAndMerge();
+
+        log.info("Generating output file {} ...", target);
+        Files.write(target, result.getBytes());
+
+        log.info("Success");
+        return 0;
+    }
+
+    String parseAndMerge() throws IOException
+    {
+        if (prettyPrinting) gsonBuilder.setPrettyPrinting();
+
+        log.info("Parsing {} ...", file1);
+        JsonObject json1 = provider.parse(Files.newInputStream(file1));
+
+        log.info("Parsing {} ...", file2);
+        JsonObject json2 = provider.parse(Files.newInputStream(file2));
+
+        JsonMergeOption[] mergeOptions = parseJsonMergeOptions();
+        JsonObject result = new JsonMerger<>(JsonObject.class)
+                .merge(json1, json2, mergeOptions);
+
+        return toString(result);
+    }
+
+    JsonMergeOption[] parseJsonMergeOptions()
+    {
+        return distinctKeys.entrySet().stream()
+                .map(this::parseJsonMergeOption)
+                .toArray(JsonMergeOption[]::new);
+    }
+
+    private JsonMergeOption parseJsonMergeOption(Entry<String, String> entry)
+    {
+        JsonMergeOption mergeOption = JsonMergeOption.onPath(entry.getKey())
+                .findObjectsIdentifiedBy(split(entry.getValue()))
+                .thenDoADeepMerge();
+        log.info("Parsed {}", mergeOption);
+        return mergeOption;
+    }
+
+    private String[] split(String string)
+    {
+        return string.split(",");
+    }
+
+    private String toString(JsonObject json)
+    {
+        return gsonBuilder.create().toJson(json);
+    }
+
+    /**
+     * @param args the command line arguments to parse
+     */
+    public static void main(String[] args)
+    {
+        System.exit(new CommandLine(new Main()).setCommandName(COMMAND_NAME).execute(args));
+    }
+
+}