Merge pull request #2 from eugenp/master

Merge

core-java-io/src/test/java/com/baeldung/filechannel/FileChannelUnitTest.java

@@ -0,0 +1,165 @@
+package com.baeldung.filechannel;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.io.ByteArrayOutputStream;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.charset.StandardCharsets;
+
+import org.junit.Test;
+
+public class FileChannelUnitTest {
+
+    @Test
+    public void givenFile_whenReadWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel(); 
+            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+
+            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+            assertEquals("Hello world", fileContent);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadWithFileChannelUsingFileInputStream_thenCorrect() throws IOException {
+
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
+            FileInputStream fin = new FileInputStream("src/test/resources/test_read.in"); 
+            FileChannel channel = fin.getChannel();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+            assertEquals("Hello world", fileContent);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadAFileSectionIntoMemoryWithFileChannel_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel(); 
+            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
+
+            MappedByteBuffer buff = channel.map(FileChannel.MapMode.READ_ONLY, 6, 5);
+
+            if (buff.hasRemaining()) {
+                byte[] data = new byte[buff.remaining()];
+                buff.get(data);
+                assertEquals("world", new String(data, StandardCharsets.UTF_8));
+            }
+        }
+    }
+
+    @Test
+    public void whenWriteWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
+        String file = "src/test/resources/test_write_using_filechannel.txt";
+        try (RandomAccessFile writer = new RandomAccessFile(file, "rw"); 
+            FileChannel channel = writer.getChannel();) {
+            ByteBuffer buff = ByteBuffer.wrap("Hello world".getBytes(StandardCharsets.UTF_8));
+
+            channel.write(buff);
+
+            // now we verify whether the file was written correctly
+            RandomAccessFile reader = new RandomAccessFile(file, "r");
+            assertEquals("Hello world", reader.readLine());
+            reader.close();
+        }
+    }
+
+    @Test
+    public void givenFile_whenWriteAFileUsingLockAFileSectionWithFileChannel_thenCorrect() throws IOException {
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "rw"); 
+            FileChannel channel = reader.getChannel(); 
+            FileLock fileLock = channel.tryLock(6, 5, Boolean.FALSE);) {
+
+            assertNotNull(fileLock);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadWithFileChannelGetPosition_thenCorrect() throws IOException {
+
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
+            RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+
+            // the original file is 11 bytes long, so that's where the position pointer should be
+            assertEquals(11, channel.position());
+
+            channel.position(4);
+            assertEquals(4, channel.position());
+        }
+    }
+
+    @Test
+    public void whenGetFileSize_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel();) {
+
+            // the original file is 11 bytes long, so that's where the position pointer should be
+            assertEquals(11, channel.size());
+        }
+    }
+
+    @Test
+    public void whenTruncateFile_thenCorrect() throws IOException {
+        String input = "this is a test input";
+
+        FileOutputStream fout = new FileOutputStream("src/test/resources/test_truncate.txt");
+        FileChannel channel = fout.getChannel();
+
+        ByteBuffer buff = ByteBuffer.wrap(input.getBytes());
+        channel.write(buff);
+        buff.flip();
+
+        channel = channel.truncate(5);
+        assertEquals(5, channel.size());
+
+        fout.close();
+        channel.close();
+    }
+}

core-java-io/src/test/resources/test_truncate.txt

@@ -0,0 +1 @@
+this 

core-java-io/src/test/resources/test_write_using_filechannel.txt

@@ -0,0 +1 @@
+Hello world

guava-collections-set/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

guava-collections-set/pom.xml

@@ -0,0 +1,37 @@
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>guava-collections-set</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>guava-collections-set</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>guava-collections-set</finalName>
+    </build>
+
+    <properties>
+        <!-- util -->
+        <guava.version>27.1-jre</guava.version>
+        <!-- testing -->
+        <assertj.version>3.6.1</assertj.version>
+    </properties>
+
+</project>

guava-collections-set/src/test/java/org/baeldung/guava/GuavaMultiSetUnitTest.java

@@ -0,0 +1,92 @@
+package org.baeldung.guava;
+
+import com.google.common.collect.HashMultiset;
+import com.google.common.collect.Multiset;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+public class GuavaMultiSetUnitTest {
+
+    @Test
+    public void givenMultiSet_whenAddingValues_shouldReturnCorrectCount() {
+        Multiset<String> bookStore = HashMultiset.create();
+        bookStore.add("Potter");
+        bookStore.add("Potter");
+        bookStore.add("Potter");
+
+        assertThat(bookStore.contains("Potter")).isTrue();
+        assertThat(bookStore.count("Potter")).isEqualTo(3);
+    }
+
+    @Test
+    public void givenMultiSet_whenRemovingValues_shouldReturnCorrectCount() {
+        Multiset<String> bookStore = HashMultiset.create();
+        bookStore.add("Potter");
+        bookStore.add("Potter");
+
+        bookStore.remove("Potter");
+        assertThat(bookStore.contains("Potter")).isTrue();
+        assertThat(bookStore.count("Potter")).isEqualTo(1);
+    }
+
+    @Test
+    public void givenMultiSet_whenSetCount_shouldReturnCorrectCount() {
+        Multiset<String> bookStore = HashMultiset.create();
+        bookStore.setCount("Potter", 50);
+        assertThat(bookStore.count("Potter")).isEqualTo(50);
+    }
+
+    @Test
+    public void givenMultiSet_whenSettingNegativeCount_shouldThrowException() {
+        Multiset<String> bookStore = HashMultiset.create();
+        assertThatThrownBy(() -> bookStore.setCount("Potter", -1))
+          .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    public void givenMultiSet_whenSettingCountWithEmptySet_shouldBeSuccessful() {
+        Multiset<String> bookStore = HashMultiset.create();
+        assertThat(bookStore.setCount("Potter", 0, 2)).isTrue();
+    }
+
+    @Test
+    public void givenMultiSet_whenSettingCountWithCorrectValue_shouldBeSuccessful() {
+        Multiset<String> bookStore = HashMultiset.create();
+        bookStore.add("Potter");
+        bookStore.add("Potter");
+
+        assertThat(bookStore.setCount("Potter", 2, 52)).isTrue();
+    }
+
+    @Test
+    public void givenMultiSet_whenSettingCountWithIncorrectValue_shouldFail() {
+        Multiset<String> bookStore = HashMultiset.create();
+        bookStore.add("Potter");
+        bookStore.add("Potter");
+
+        assertThat(bookStore.setCount("Potter", 5, 52)).isFalse();
+    }
+
+    @Test
+    public void givenMap_compareMultiSetOperations() {
+        Map<String, Integer> bookStore = new HashMap<>();
+        bookStore.put("Potter", 3);
+
+        assertThat(bookStore.containsKey("Potter")).isTrue();
+        assertThat(bookStore.get("Potter")).isEqualTo(3);
+
+        bookStore.put("Potter", 2);
+        assertThat(bookStore.get("Potter")).isEqualTo(2);
+
+        bookStore.put("Potter", null);
+        assertThat(bookStore.containsKey("Potter")).isTrue();
+
+        bookStore.put("Potter", -1);
+        assertThat(bookStore.containsKey("Potter")).isTrue();
+    }
+}

jackson-simple/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

jackson-simple/README.md

@@ -0,0 +1,13 @@
+=========
+### Jackson Articles that are also part of the e-book
+
+###The Course
+The "REST With Spring" Classes: http://bit.ly/restwithspring
+
+### Relevant Articles: 
+- [Jackson Ignore Properties on Marshalling](http://www.baeldung.com/jackson-ignore-properties-on-serialization)
+- [Jackson Unmarshalling json with Unknown Properties](http://www.baeldung.com/jackson-deserialize-json-unknown-properties)
+- [Jackson Annotation Examples](http://www.baeldung.com/jackson-annotations)
+- [Intro to the Jackson ObjectMapper](http://www.baeldung.com/jackson-object-mapper-tutorial)
+- [Ignore Null Fields with Jackson](http://www.baeldung.com/jackson-ignore-null-fields)
+- [Jackson – Change Name of Field](http://www.baeldung.com/jackson-name-of-property)

jackson-simple/pom.xml

@@ -0,0 +1,131 @@
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>jackson-simple</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>jackson-simple</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- utils -->
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+        <!--jackson for xml -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-xml</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+
+        <!-- marshalling -->
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jsr310</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-joda</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-jsonSchema</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jdk8</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>joda-time</groupId>
+            <artifactId>joda-time</artifactId>
+            <version>${joda-time.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+
+        <!-- test scoped -->
+
+        <dependency>
+            <groupId>io.rest-assured</groupId>
+            <artifactId>json-schema-validator</artifactId>
+            <version>${rest-assured.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>io.rest-assured</groupId>
+            <artifactId>json-path</artifactId>
+            <version>${rest-assured.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>jackson-simple</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <!-- util -->
+        <commons-lang3.version>3.8</commons-lang3.version>
+        <joda-time.version>2.10</joda-time.version>
+        <gson.version>2.8.5</gson.version>
+        <commons-collections4.version>4.2</commons-collections4.version>
+
+        <!-- testing -->
+        <rest-assured.version>3.1.1</rest-assured.version>
+        <assertj.version>3.11.0</assertj.version>
+    </properties>
+
+</project>

jackson-simple/src/main/resources/logback.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/ItemWithIdentity.java

@@ -0,0 +1,21 @@
+package com.baeldung.jackson.bidirection;
+
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.ObjectIdGenerators;
+
+@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
+public class ItemWithIdentity {
+    public int id;
+    public String itemName;
+    public UserWithIdentity owner;
+
+    public ItemWithIdentity() {
+        super();
+    }
+
+    public ItemWithIdentity(final int id, final String itemName, final UserWithIdentity owner) {
+        this.id = id;
+        this.itemName = itemName;
+        this.owner = owner;
+    }
+}

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/ItemWithIgnore.java

@@ -0,0 +1,17 @@
+package com.baeldung.jackson.bidirection;
+
+public class ItemWithIgnore {
+    public int id;
+    public String itemName;
+    public UserWithIgnore owner;
+
+    public ItemWithIgnore() {
+        super();
+    }
+
+    public ItemWithIgnore(final int id, final String itemName, final UserWithIgnore owner) {
+        this.id = id;
+        this.itemName = itemName;
+        this.owner = owner;
+    }
+}

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/ItemWithRef.java

@@ -0,0 +1,21 @@
+package com.baeldung.jackson.bidirection;
+
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+
+public class ItemWithRef {
+    public int id;
+    public String itemName;
+
+    @JsonManagedReference
+    public UserWithRef owner;
+
+    public ItemWithRef() {
+        super();
+    }
+
+    public ItemWithRef(final int id, final String itemName, final UserWithRef owner) {
+        this.id = id;
+        this.itemName = itemName;
+        this.owner = owner;
+    }
+}

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/UserWithIdentity.java

@@ -0,0 +1,28 @@
+package com.baeldung.jackson.bidirection;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.ObjectIdGenerators;
+
+@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
+public class UserWithIdentity {
+    public int id;
+    public String name;
+    public List<ItemWithIdentity> userItems;
+
+    public UserWithIdentity() {
+        super();
+    }
+
+    public UserWithIdentity(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+        userItems = new ArrayList<ItemWithIdentity>();
+    }
+
+    public void addItem(final ItemWithIdentity item) {
+        userItems.add(item);
+    }
+}

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/UserWithIgnore.java

@@ -0,0 +1,28 @@
+package com.baeldung.jackson.bidirection;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+public class UserWithIgnore {
+    public int id;
+    public String name;
+
+    @JsonIgnore
+    public List<ItemWithIgnore> userItems;
+
+    public UserWithIgnore() {
+        super();
+    }
+
+    public UserWithIgnore(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+        userItems = new ArrayList<ItemWithIgnore>();
+    }
+
+    public void addItem(final ItemWithIgnore item) {
+        userItems.add(item);
+    }
+}

jackson-simple/src/test/java/com/baeldung/jackson/bidirection/UserWithRef.java

@@ -0,0 +1,28 @@
+package com.baeldung.jackson.bidirection;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonBackReference;
+
+public class UserWithRef {
+    public int id;
+    public String name;
+
+    @JsonBackReference
+    public List<ItemWithRef> userItems;
+
+    public UserWithRef() {
+        super();
+    }
+
+    public UserWithRef(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+        userItems = new ArrayList<ItemWithRef>();
+    }
+
+    public void addItem(final ItemWithRef item) {
+        userItems.add(item);
+    }
+}