Lazy refactoring

Author: cardil

src/main/java/pl/wavesoftware/eid/Eid.java

@@ -18,6 +18,8 @@
 import pl.wavesoftware.eid.configuration.Binding;
 import pl.wavesoftware.eid.configuration.Configurator;
 import pl.wavesoftware.eid.configuration.Validator;
+import pl.wavesoftware.eid.impl.SerializableSupplier;
+import pl.wavesoftware.eid.impl.Supplier;
 
 import javax.annotation.Nullable;
 import java.io.Serializable;
@@ -112,7 +114,18 @@ public class Eid implements Serializable {
     private transient String id;
     @Nullable
     private transient String ref;
-    private String uniqueId;
+    private final SerializableSupplier<String> uniqueId = MODULE
+        .getBinding()
+        .lazy(new Supplier<String>() {
+            @Override
+            public String get() {
+                return MODULE.getBinding()
+                    .getConfigurationSystem()
+                    .getConfiguration()
+                    .getIdGenerator()
+                    .generateUniqId();
+            }
+        });
 
     /**
      * Constructor a single value of exception ID.
@@ -191,10 +204,7 @@ public boolean hasRef() {
      * @return a unique string
      */
     public String getUnique() {
-        if (uniqueId == null) {
-            uniqueId = doGetUniqueId();
-        }
-        return uniqueId;
+        return uniqueId.get();
     }
 
     /**
@@ -227,17 +237,6 @@ public String toString() {
             .format(this);
     }
 
-    private synchronized String doGetUniqueId() {
-        if (uniqueId == null) {
-            return MODULE.getBinding()
-                .getConfigurationSystem()
-                .getConfiguration()
-                .getIdGenerator()
-                .generateUniqId();
-        }
-        return uniqueId;
-    }
-
     /*
     Suppress warnings id here for null check. Users can pass null event if it's
     forbidden.

src/main/java/pl/wavesoftware/eid/configuration/Binding.java

@@ -18,6 +18,10 @@
 
 import pl.wavesoftware.eid.Eid;
 import pl.wavesoftware.eid.EidMessage;
+import pl.wavesoftware.eid.impl.SerializableSupplier;
+import pl.wavesoftware.eid.impl.Supplier;
+
+import java.io.Serializable;
 
 /**
  * A binding of Eid library. This interface can be used to completely
@@ -64,4 +68,13 @@ EidMessage createEidMessage(
         CharSequence messageTemplate,
         Object[] templateArguments
     );
+
+    /**
+     * Creates a lazy supplier of a given supplier of serializable value
+     *
+     * @param supplier a supplier of serializable value
+     * @param <T> a serializable type
+     * @return a lazy, serializable, supplier
+     */
+    <T extends Serializable> SerializableSupplier<T> lazy(Supplier<T> supplier);
 }

src/main/java/pl/wavesoftware/eid/impl/BindingImpl.java

@@ -21,7 +21,11 @@
 import pl.wavesoftware.eid.configuration.Binding;
 import pl.wavesoftware.eid.configuration.ConfigurationSystem;
 
+import java.io.Serializable;
+
 /**
+ * A default binding implementation.
+ *
  * @author <a href="mailto:krzysztof.suszynski@wavesoftware.pl">Krzysztof Suszynski</a>
  * @since 2.0.0
  */
@@ -47,4 +51,9 @@ public EidMessage createEidMessage(
             templateArguments
         );
     }
+
+    @Override
+    public <T extends Serializable> SerializableSupplier<T> lazy(Supplier<T> supplier) {
+        return SerializableLazy.of(supplier);
+    }
 }

src/main/java/pl/wavesoftware/eid/impl/ConfigurationSystemImpl.java

@@ -29,54 +29,46 @@
  */
 final class ConfigurationSystemImpl implements ConfigurationSystem {
 
-    private volatile MutableConfiguration configuration;
+    private Lazy<MutableConfiguration> configuration =
+        Lazy.of(new MutableConfigurationSupplier());
 
     ConfigurationSystemImpl() {
         // nothing here
     }
 
     @Override
     public Configuration getConfiguration() {
-        if (configuration == null) {
-            configuration = getMutableConfiguration();
-        }
-        return configuration;
+        return configuration.get();
     }
 
-    /**
-     * Configures an Eid library programmatically.
-     *
-     * @param configurator a configurator to use to configure Eid library
-     * @return a reference to a configurator that can be used to restore
-     * previous configuration
-     */
     @Override
     public Configurator configure(Configurator configurator) {
-        // ensure system configuration are loaded
-        getConfiguration();
-        MutableConfiguration configuredSettings = configuration;
-        configuration = new ConfigurationImpl(configuredSettings);
-        configurator.configure(configuration);
-        return new RestoreConfigurator(configuredSettings);
+        MutableConfiguration configured = configuration.get();
+        MutableConfiguration mutable = new ConfigurationImpl(configured);
+        configurator.configure(mutable);
+        configuration = Lazy.of(mutable);
+        return new RestoreConfigurator(configured);
     }
 
-    private synchronized MutableConfiguration getMutableConfiguration() {
-        if (configuration == null) {
+    private static final class MutableConfigurationSupplier
+        implements Supplier<MutableConfiguration> {
+
+        @Override
+        public MutableConfiguration get() {
             return loadConfiguration();
         }
-        return configuration;
-    }
 
-    private static MutableConfiguration loadConfiguration() {
-        MutableConfiguration mutableConfiguration = new ConfigurationImpl();
-        new DefaultConfigurator().configure(mutableConfiguration);
-        ServiceLoader<Configurator> configurators =
-            ServiceLoader.load(Configurator.class);
+        private static MutableConfiguration loadConfiguration() {
+            MutableConfiguration mutableConfiguration = new ConfigurationImpl();
+            new DefaultConfigurator().configure(mutableConfiguration);
+            ServiceLoader<Configurator> configurators =
+                ServiceLoader.load(Configurator.class);
 
-        for (Configurator configurator : configurators) {
-            configurator.configure(mutableConfiguration);
+            for (Configurator configurator : configurators) {
+                configurator.configure(mutableConfiguration);
+            }
+            return mutableConfiguration;
         }
-        return mutableConfiguration;
     }
 
     private static final class RestoreConfigurator

src/main/java/pl/wavesoftware/eid/impl/EidTextRepresentation.java

@@ -20,8 +20,6 @@
 import pl.wavesoftware.eid.EidContainer;
 import pl.wavesoftware.eid.configuration.Configuration;
 
-import java.io.IOException;
-import java.io.ObjectOutputStream;
 import java.io.Serializable;
 
 /**
@@ -33,17 +31,22 @@ final class EidTextRepresentation implements EidContainer, Serializable {
 
     private final Eid eid;
     private final TextMessage textMessage;
-    private transient Configuration configuration;
-    private String actual;
+    private final SerializableLazy<String> actual;
 
     EidTextRepresentation(
-        Eid eid,
-        TextMessage textMessage,
-        Configuration configuration
+        final Eid eid,
+        final TextMessage textMessage,
+        final Configuration configuration
     ) {
         this.eid = eid;
         this.textMessage = textMessage;
-        this.configuration = configuration;
+        this.actual = SerializableLazy.of(new Supplier<String>() {
+            @Override
+            public String get() {
+                return configuration.getFormatter()
+                    .format(eid, textMessage.get());
+            }
+        });
     }
 
     @Override
@@ -56,30 +59,6 @@ TextMessage getTextMessage() {
     }
 
     String get() {
-        if (actual == null) {
-            actual = doGet();
-            configuration = null;
-        }
-        return actual;
-    }
-
-    private synchronized String doGet() {
-        if (actual == null) {
-            return configuration.getFormatter()
-                .format(eid, textMessage.get());
-        }
-        return actual;
-    }
-
-    /**
-     * Ensures that the value is evaluated before serialization.
-     *
-     * @param stream An object serialization stream.
-     * @throws java.io.IOException If an error occurs writing to the stream.
-     */
-    private void writeObject(ObjectOutputStream stream) throws IOException {
-        // evaluates the values if it isn't evaluated yet!
-        get();
-        stream.defaultWriteObject();
+        return actual.get();
     }
 }

src/main/java/pl/wavesoftware/eid/impl/InternalChecks.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2018 Wave Software
+ *
+ * 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 pl.wavesoftware.eid.impl;
+
+import javax.annotation.Nullable;
+
+/**
+ * @author <a href="mailto:krzysztof.suszynski@wavesoftware.pl">Krzysztof Suszynski</a>
+ * @since 2.0.0
+ */
+final class InternalChecks {
+    private InternalChecks() {
+        // nothing here
+    }
+
+    @SuppressWarnings("squid:S1695")
+    static <T> T checkNotNull(@Nullable T value, String message) {
+        if (value == null) {
+            throw new IllegalArgumentException(message);
+        }
+        return value;
+    }
+}

src/main/java/pl/wavesoftware/eid/impl/Lazy.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2018 Wave Software
+ *
+ * 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 pl.wavesoftware.eid.impl;
+
+import static pl.wavesoftware.eid.impl.InternalChecks.checkNotNull;
+
+
+/**
+ * @author <a href="mailto:krzysztof.suszynski@wavesoftware.pl">Krzysztof Suszynski</a>
+ * @since 2.0.0
+ */
+class Lazy<T> implements Supplier<T> {
+    private Supplier<T> supplier;
+    private T value;
+
+    Lazy(Supplier<T> supplier) {
+        this.supplier = checkNotNull(supplier, "20181124:004511");
+    }
+
+    protected Lazy() {
+        // nothing
+    }
+
+    private Lazy(T value) {
+        this.value = value;
+    }
+
+    static <R> Lazy<R> of(Supplier<R> supplier) {
+        return new Lazy<R>(supplier);
+    }
+
+    static <R> Lazy<R> of(R value) {
+        return new Lazy<R>(value);
+    }
+
+    @Override
+    public T get() {
+        if (supplier != null) {
+            value = doGet();
+        }
+        return value;
+    }
+
+    private synchronized T doGet() {
+        if (supplier != null) {
+            T calculated = supplier.get();
+            supplier = null;
+            return calculated;
+        }
+        return value;
+    }
+}