initial commit

.gitignore

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+*.iml
+.idea/
+target/

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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>de.joshavg</groupId>
+    <artifactId>simpledic</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>SimpleDiContainer</name>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.collections</groupId>
+            <artifactId>google-collections</artifactId>
+            <version>1.0</version>
+        </dependency>
+    </dependencies>
+
+
+</project>

src/main/java/de/joshavg/simpledic/SdiContainer.java

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+package de.joshavg.simpledic;
+
+import com.google.common.annotations.VisibleForTesting;
+import de.joshavg.simpledic.exception.ContainerInitException;
+import de.joshavg.simpledic.exception.DependencyNotSatisfiedException;
+import de.joshavg.simpledic.exception.SdicClassNotFoundException;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.reflect.Constructor;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Properties;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class SdiContainer {
+
+    private final Properties props;
+
+    @VisibleForTesting
+    SdiContainer(Properties props) {
+        this.props = props;
+    }
+
+    public static SdiContainer load() {
+        return load("sdic.properties");
+    }
+
+    public static SdiContainer load(String filename) {
+        Properties props = new Properties();
+
+        InputStream inputStream = SdiContainer.class.getClassLoader().getResourceAsStream(filename);
+        try {
+            props.load(inputStream);
+        } catch (IOException e) {
+            throw new ContainerInitException("failed loading properties", e);
+        }
+
+        SdiContainer container = new SdiContainer(props);
+        container.integrityCheck();
+        return container;
+    }
+
+    private void integrityCheck() {
+        List<Class<?>> services = fetchAllServices();
+        checkConstructorDependencies(services);
+    }
+
+    private List<Class<?>> fetchAllServices() {
+        return props.entrySet().stream()
+                    .filter(e -> isServiceName(e.getKey().toString()))
+                    .map(e -> e.getValue().toString())
+                    .map(n -> {
+                        try {
+                            return Class.forName(n);
+                        } catch (ClassNotFoundException e) {
+                            throw new SdicClassNotFoundException(e);
+                        }
+                    }).collect(Collectors.toList());
+    }
+
+    private void checkConstructorDependencies(List<Class<?>> services) {
+        for(Class<?> c : services) {
+            Constructor<?>[] constructors = c.getDeclaredConstructors();
+            for(Constructor constructor : constructors) {
+                Class[] parameterTypes = constructor.getParameterTypes();
+                System.out.println(Arrays.toString(parameterTypes));
+                System.out.println(Arrays.asList(parameterTypes));
+            }
+        }
+      /*  services.stream()
+                // get all constructors
+                .map(Class::getDeclaredConstructors)
+                .reduce(new ArrayList<Constructor>(),
+                        (l, arr) -> {
+                            l.addAll(Arrays.asList(arr));
+                            return l;
+                        },
+                        (l1, l2) -> l1)
+                // get all parameter types
+                .stream()
+                .map(Constructor::getParameterTypes)
+                .reduce(new ArrayList<Class<?>>(),
+                        (l, arr) -> {
+                            l.addAll(Arrays.asList(arr));
+                            return l;
+                        },
+                        (l1, l2) -> l1)
+                // search for services with needed types
+                .stream()
+                .distinct()
+                .forEach(t -> {
+                    if (!services.contains(t)) {
+                        throw new DependencyNotSatisfiedException(t);
+                    }
+                });*/
+    }
+
+    @VisibleForTesting
+    static boolean isServiceName(String name) {
+        return name.startsWith("service.");
+    }
+}

src/main/java/de/joshavg/simpledic/exception/ContainerInitException.java

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+package de.joshavg.simpledic.exception;
+
+public class ContainerInitException extends RuntimeException {
+
+    public ContainerInitException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/de/joshavg/simpledic/exception/DependencyNotSatisfiedException.java

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+package de.joshavg.simpledic.exception;
+
+public class DependencyNotSatisfiedException extends RuntimeException {
+    public DependencyNotSatisfiedException(Class<?> dependency) {
+        super(String.format("Dependency %s not satisfied", dependency.getName()));
+    }
+}

src/main/java/de/joshavg/simpledic/exception/NoDefaultConstructorException.java

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+package de.joshavg.simpledic.exception;
+
+public class NoDefaultConstructorException extends RuntimeException {
+    public NoDefaultConstructorException(Throwable cause) {
+        super(cause);
+    }
+}

src/main/java/de/joshavg/simpledic/exception/SdicClassNotFoundException.java

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+package de.joshavg.simpledic.exception;
+
+public class SdicClassNotFoundException extends RuntimeException {
+    public SdicClassNotFoundException(Throwable cause) {
+        super(cause);
+    }
+}

src/test/java/de/joshavg/simpledic/NoDependencies.java

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+package de.joshavg.simpledic;
+
+public class NoDependencies {
+}

src/test/java/de/joshavg/simpledic/ServiceOne.java

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+package de.joshavg.simpledic;
+
+public class ServiceOne {
+    public ServiceOne(NoDependencies b) {
+    }
+}

src/test/java/de/joshavg/simpledic/TestProperties.java

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+package de.joshavg.simpledic;
+
+import org.junit.Test;
+
+public class TestProperties {
+
+    @Test
+    public void testIntegrityCheck() {
+        SdiContainer.load("test.properties");
+    }
+}

src/test/resources/test.properties

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+service.one: de.joshavg.simpledic.ServiceOne
+service.nodeps: de.joshavg.simpledic.NoDependencies