odata2-annotation-processor/annotation-processor-core/src/main/java/org/apache/olingo/odata2/annotation/processor/core/datasource/DataStore.java - olingo-odata2 - Git at Google

 /*******************************************************************************
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements. See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership. The ASF licenses this file
  * to you 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 org.apache.olingo.odata2.annotation.processor.core.datasource;

 import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;

 import org.apache.olingo.odata2.annotation.processor.core.util.AnnotationHelper;
 import org.apache.olingo.odata2.annotation.processor.core.util.AnnotationRuntimeException;
 import org.apache.olingo.odata2.annotation.processor.core.util.ClassHelper;
 import org.apache.olingo.odata2.api.annotation.edm.EdmKey;
 import org.apache.olingo.odata2.api.exception.ODataApplicationException;

 /**
  *
  */
 public class DataStore<T> {

   private static final AnnotationHelper ANNOTATION_HELPER = new AnnotationHelper();
   private final Map<KeyElement, T> dataStore;
   private final Class<T> dataTypeClass;
   private final KeyAccess keyAccess;

   private static class InMemoryDataStore {
     private static final Map<Class<?>, DataStore<?>> c2ds = new HashMap<Class<?>, DataStore<?>>();

     @SuppressWarnings("unchecked")
     static synchronized DataStore<?> getInstance(final Class<?> clz, final boolean createNewInstance)
         throws DataStoreException {
       DataStore<?> ds = c2ds.get(clz);
       if (createNewInstance || ds == null) {
         ds = new DataStore<Object>((Class<Object>) clz);
         c2ds.put(clz, ds);
       }
       return ds;
     }
   }

   @SuppressWarnings("unchecked")
   public static <T> DataStore<T> createInMemory(final Class<T> clazz) throws DataStoreException {
     return (DataStore<T>) InMemoryDataStore.getInstance(clazz, true);
   }

   @SuppressWarnings("unchecked")
   public static <T> DataStore<T> createInMemory(final Class<T> clazz, final boolean keepExisting)
       throws DataStoreException {
     return (DataStore<T>) InMemoryDataStore.getInstance(clazz, !keepExisting);
   }

   private DataStore(final Map<KeyElement, T> wrapStore, final Class<T> clz) throws DataStoreException {
     dataStore = Collections.synchronizedMap(wrapStore);
     dataTypeClass = clz;
     keyAccess = new KeyAccess(clz);
   }

   private DataStore(final Class<T> clz) throws DataStoreException {
     this(new HashMap<KeyElement, T>(), clz);
   }

   public Class<T> getDataTypeClass() {
     return dataTypeClass;
   }

   public String getEntityTypeName() {
     return ANNOTATION_HELPER.extractEntityTypeName(dataTypeClass);
   }

   public T createInstance() {
     try {
       return dataTypeClass.newInstance();
     } catch (InstantiationException e) {
       throw new AnnotationRuntimeException("Unable to create instance of class '" + dataTypeClass + "'.", e);
     } catch (IllegalAccessException e) {
       throw new AnnotationRuntimeException("Unable to create instance of class '" + dataTypeClass + "'.", e);
     }
   }

   public T read(final T obj) {
     KeyElement objKeys = getKeys(obj);
     return dataStore.get(objKeys);
   }

   public Collection<T> read() {
     return Collections.unmodifiableCollection(dataStore.values());
   }

   public T create(final T object) throws DataStoreException {
     KeyElement keyElement = getKeys(object);
     return create(object, keyElement);
   }

   /**
    * Store an entity, preserving any existing keys if possible. If the combination of
    * existing and generated keys would produce a duplicate entry, replace all keys.
    */
   private T create(final T object, final KeyElement keyElement) throws DataStoreException {
     synchronized (dataStore) {
       final boolean replaceKeys = dataStore.containsKey(keyElement);
       if (keyElement.keyValuesMissing() || replaceKeys) {
         KeyElement newKey = createSetAndGetKeys(object, replaceKeys);
         return this.create(object, newKey);
       }
       dataStore.put(keyElement, object);
     }
     return object;
   }

   public T update(final T object) {
     KeyElement keyElement = getKeys(object);
     synchronized (dataStore) {
       dataStore.remove(keyElement);
       dataStore.put(keyElement, object);
     }
     return object;
   }

   public T delete(final T object) {
     KeyElement keyElement = getKeys(object);
     synchronized (dataStore) {
       return dataStore.remove(keyElement);
     }
   }

   /**
    * Are the key values equal for both instances.
    * If all compared key values are <code>null</code> this also means equal.
    *
    * @param first first instance to check for key equal
    * @param second second instance to check for key equal
    * @return <code>true</code> if object instance have equal keys set.
    */
   public boolean isKeyEqual(final T first, final T second) {
     KeyElement firstKeys = getKeys(first);
     KeyElement secondKeys = getKeys(second);

     return firstKeys.equals(secondKeys);
   }

   /**
    * Are the key values equal for both instances.
    * If all compared key values are <code>null</code> this also means equal.
    * Before object (keys) are compared it is validated that both object instance are NOT null
    * and that both are from the same class as this {@link DataStore} (see {@link #dataTypeClass}).
    * For the equal check on {@link #dataTypeClass} instances without validation see {@link #isKeyEqual(Object, Object)}.
    *
    * @param first first instance to check for key equal
    * @param second second instance to check for key equal
    * @return <code>true</code> if object instance have equal keys set.
    */
   @SuppressWarnings("unchecked")
   public boolean isKeyEqualChecked(final Object first, final Object second) throws DataStoreException {
     if (first == null || second == null) {
       throw new DataStoreException("Tried to compare null values which is not allowed.");
     } else if (first.getClass() != dataTypeClass) {
       throw new DataStoreException("First value is no instance from required class '" + dataTypeClass + "'.");
     } else if (second.getClass() != dataTypeClass) {
       throw new DataStoreException("Second value is no instance from required class '" + dataTypeClass + "'.");
     }

     return isKeyEqual((T) first, (T) second);
   }

   private class KeyElement {
     private int cachedHashCode = 42;
     private final List<Object> keyValues;

     public KeyElement(final int size) {
       keyValues = new ArrayList<Object>(size);
     }

     private void addValue(final Object keyValue) {
       keyValues.add(keyValue);
       cachedHashCode = 89 * cachedHashCode + (keyValue != null ? keyValue.hashCode() : 0);
     }

     boolean keyValuesMissing() {
       return keyValues.contains(null);
     }

     @Override
     public int hashCode() {
       return cachedHashCode;
     }

     @Override
     public boolean equals(final Object obj) {
       if (obj == null) {
         return false;
       }
       if (getClass() != obj.getClass()) {
         return false;
       }
       @SuppressWarnings("unchecked")
       final KeyElement other = (KeyElement) obj;
       if (this.keyValues != other.keyValues && (this.keyValues == null || !this.keyValues.equals(other.keyValues))) {
         return false;
       }
       return true;
     }

     @Override
     public String toString() {
       return "KeyElement{" + "cachedHashCode=" + cachedHashCode + ", keyValues=" + keyValues + '}';
     }
   }

   private class KeyAccess {
     final List<Field> keyFields;
     final AtomicInteger idCounter = new AtomicInteger(1);

     KeyAccess(final Class<?> clazz) throws DataStoreException {
       keyFields = ANNOTATION_HELPER.getAnnotatedFields(clazz, EdmKey.class);
       if (keyFields.isEmpty()) {
         throw new DataStoreException("No EdmKey annotated fields found for class " + clazz);
       }
     }

     KeyElement getKeyValues(final T object) {
       KeyElement keyElement = new KeyElement(keyFields.size());
       for (Field field : keyFields) {
         Object keyValue = ClassHelper.getFieldValue(object, field);
         keyElement.addValue(keyValue);
       }

       return keyElement;
     }

     KeyElement createSetAndGetKeys(final T object, boolean replaceKeys) throws DataStoreException {
       KeyElement keyElement = new KeyElement(keyFields.size());
       for (Field field : keyFields) {
         Object key = ClassHelper.getFieldValue(object, field);
         if (key == null || replaceKeys) {
           key = createKey(field);
           ClassHelper.setFieldValue(object, field, key);
         }
         keyElement.addValue(key);
       }

       return keyElement;
     }

     private Object createKey(final Field field) {
       Class<?> type = field.getType();

       if (type == String.class) {
         return String.valueOf(idCounter.getAndIncrement());
       } else if (type == Integer.class || type == int.class) {
         return Integer.valueOf(idCounter.getAndIncrement());
       } else if (type == Long.class || type == long.class) {
         return Long.valueOf(idCounter.getAndIncrement());
       } else if (type == UUID.class) {
         return UUID.randomUUID();
       }

       throw new UnsupportedOperationException("Automated key generation for type '" + type
           + "' is not supported (caused on field '" + field + "').");
     }
   }

   private KeyElement getKeys(final T object) {
     return keyAccess.getKeyValues(object);
   }

   private KeyElement createSetAndGetKeys(final T object, boolean replaceKeys) throws DataStoreException {
     return keyAccess.createSetAndGetKeys(object, replaceKeys);
   }

   public static class DataStoreException extends ODataApplicationException {
     private static final long serialVersionUID = 42L;

     public DataStoreException(final String message) {
       this(message, null);
     }

     public DataStoreException(final String message, final Throwable cause) {
       super(message, Locale.ENGLISH, cause);
     }
   }
 }
	/*******************************************************************************
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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 org.apache.olingo.odata2.annotation.processor.core.datasource;

	import java.lang.reflect.Field;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Locale;
	import java.util.Map;
	import java.util.UUID;
	import java.util.concurrent.atomic.AtomicInteger;

	import org.apache.olingo.odata2.annotation.processor.core.util.AnnotationHelper;
	import org.apache.olingo.odata2.annotation.processor.core.util.AnnotationRuntimeException;
	import org.apache.olingo.odata2.annotation.processor.core.util.ClassHelper;
	import org.apache.olingo.odata2.api.annotation.edm.EdmKey;
	import org.apache.olingo.odata2.api.exception.ODataApplicationException;

	/**
	*
	*/
	public class DataStore<T> {

	private static final AnnotationHelper ANNOTATION_HELPER = new AnnotationHelper();
	private final Map<KeyElement, T> dataStore;
	private final Class<T> dataTypeClass;
	private final KeyAccess keyAccess;

	private static class InMemoryDataStore {
	private static final Map<Class<?>, DataStore<?>> c2ds = new HashMap<Class<?>, DataStore<?>>();

	@SuppressWarnings("unchecked")
	static synchronized DataStore<?> getInstance(final Class<?> clz, final boolean createNewInstance)
	throws DataStoreException {
	DataStore<?> ds = c2ds.get(clz);
	if (createNewInstance \|\| ds == null) {
	ds = new DataStore<Object>((Class<Object>) clz);
	c2ds.put(clz, ds);
	}
	return ds;
	}
	}

	@SuppressWarnings("unchecked")
	public static <T> DataStore<T> createInMemory(final Class<T> clazz) throws DataStoreException {
	return (DataStore<T>) InMemoryDataStore.getInstance(clazz, true);
	}

	@SuppressWarnings("unchecked")
	public static <T> DataStore<T> createInMemory(final Class<T> clazz, final boolean keepExisting)
	throws DataStoreException {
	return (DataStore<T>) InMemoryDataStore.getInstance(clazz, !keepExisting);
	}

	private DataStore(final Map<KeyElement, T> wrapStore, final Class<T> clz) throws DataStoreException {
	dataStore = Collections.synchronizedMap(wrapStore);
	dataTypeClass = clz;
	keyAccess = new KeyAccess(clz);
	}

	private DataStore(final Class<T> clz) throws DataStoreException {
	this(new HashMap<KeyElement, T>(), clz);
	}

	public Class<T> getDataTypeClass() {
	return dataTypeClass;
	}

	public String getEntityTypeName() {
	return ANNOTATION_HELPER.extractEntityTypeName(dataTypeClass);
	}

	public T createInstance() {
	try {
	return dataTypeClass.newInstance();
	} catch (InstantiationException e) {
	throw new AnnotationRuntimeException("Unable to create instance of class '" + dataTypeClass + "'.", e);
	} catch (IllegalAccessException e) {
	throw new AnnotationRuntimeException("Unable to create instance of class '" + dataTypeClass + "'.", e);
	}
	}

	public T read(final T obj) {
	KeyElement objKeys = getKeys(obj);
	return dataStore.get(objKeys);
	}

	public Collection<T> read() {
	return Collections.unmodifiableCollection(dataStore.values());
	}

	public T create(final T object) throws DataStoreException {
	KeyElement keyElement = getKeys(object);
	return create(object, keyElement);
	}

	/**
	* Store an entity, preserving any existing keys if possible. If the combination of
	* existing and generated keys would produce a duplicate entry, replace all keys.
	*/
	private T create(final T object, final KeyElement keyElement) throws DataStoreException {
	synchronized (dataStore) {
	final boolean replaceKeys = dataStore.containsKey(keyElement);
	if (keyElement.keyValuesMissing() \|\| replaceKeys) {
	KeyElement newKey = createSetAndGetKeys(object, replaceKeys);
	return this.create(object, newKey);
	}
	dataStore.put(keyElement, object);
	}
	return object;
	}

	public T update(final T object) {
	KeyElement keyElement = getKeys(object);
	synchronized (dataStore) {
	dataStore.remove(keyElement);
	dataStore.put(keyElement, object);
	}
	return object;
	}

	public T delete(final T object) {
	KeyElement keyElement = getKeys(object);
	synchronized (dataStore) {
	return dataStore.remove(keyElement);
	}
	}

	/**
	* Are the key values equal for both instances.
	* If all compared key values are <code>null</code> this also means equal.
	*
	* @param first first instance to check for key equal
	* @param second second instance to check for key equal
	* @return <code>true</code> if object instance have equal keys set.
	*/
	public boolean isKeyEqual(final T first, final T second) {
	KeyElement firstKeys = getKeys(first);
	KeyElement secondKeys = getKeys(second);

	return firstKeys.equals(secondKeys);
	}

	/**
	* Are the key values equal for both instances.
	* If all compared key values are <code>null</code> this also means equal.
	* Before object (keys) are compared it is validated that both object instance are NOT null
	* and that both are from the same class as this {@link DataStore} (see {@link #dataTypeClass}).
	* For the equal check on {@link #dataTypeClass} instances without validation see {@link #isKeyEqual(Object, Object)}.
	*
	* @param first first instance to check for key equal
	* @param second second instance to check for key equal
	* @return <code>true</code> if object instance have equal keys set.
	*/
	@SuppressWarnings("unchecked")
	public boolean isKeyEqualChecked(final Object first, final Object second) throws DataStoreException {
	if (first == null \|\| second == null) {
	throw new DataStoreException("Tried to compare null values which is not allowed.");
	} else if (first.getClass() != dataTypeClass) {
	throw new DataStoreException("First value is no instance from required class '" + dataTypeClass + "'.");
	} else if (second.getClass() != dataTypeClass) {
	throw new DataStoreException("Second value is no instance from required class '" + dataTypeClass + "'.");
	}

	return isKeyEqual((T) first, (T) second);
	}

	private class KeyElement {
	private int cachedHashCode = 42;
	private final List<Object> keyValues;

	public KeyElement(final int size) {
	keyValues = new ArrayList<Object>(size);
	}

	private void addValue(final Object keyValue) {
	keyValues.add(keyValue);
	cachedHashCode = 89 * cachedHashCode + (keyValue != null ? keyValue.hashCode() : 0);
	}

	boolean keyValuesMissing() {
	return keyValues.contains(null);
	}

	@Override
	public int hashCode() {
	return cachedHashCode;
	}

	@Override
	public boolean equals(final Object obj) {
	if (obj == null) {
	return false;
	}
	if (getClass() != obj.getClass()) {
	return false;
	}
	@SuppressWarnings("unchecked")
	final KeyElement other = (KeyElement) obj;
	if (this.keyValues != other.keyValues && (this.keyValues == null \|\| !this.keyValues.equals(other.keyValues))) {
	return false;
	}
	return true;
	}

	@Override
	public String toString() {
	return "KeyElement{" + "cachedHashCode=" + cachedHashCode + ", keyValues=" + keyValues + '}';
	}
	}

	private class KeyAccess {
	final List<Field> keyFields;
	final AtomicInteger idCounter = new AtomicInteger(1);

	KeyAccess(final Class<?> clazz) throws DataStoreException {
	keyFields = ANNOTATION_HELPER.getAnnotatedFields(clazz, EdmKey.class);
	if (keyFields.isEmpty()) {
	throw new DataStoreException("No EdmKey annotated fields found for class " + clazz);
	}
	}

	KeyElement getKeyValues(final T object) {
	KeyElement keyElement = new KeyElement(keyFields.size());
	for (Field field : keyFields) {
	Object keyValue = ClassHelper.getFieldValue(object, field);
	keyElement.addValue(keyValue);
	}

	return keyElement;
	}

	KeyElement createSetAndGetKeys(final T object, boolean replaceKeys) throws DataStoreException {
	KeyElement keyElement = new KeyElement(keyFields.size());
	for (Field field : keyFields) {
	Object key = ClassHelper.getFieldValue(object, field);
	if (key == null \|\| replaceKeys) {
	key = createKey(field);
	ClassHelper.setFieldValue(object, field, key);
	}
	keyElement.addValue(key);
	}

	return keyElement;
	}

	private Object createKey(final Field field) {
	Class<?> type = field.getType();

	if (type == String.class) {
	return String.valueOf(idCounter.getAndIncrement());
	} else if (type == Integer.class \|\| type == int.class) {
	return Integer.valueOf(idCounter.getAndIncrement());
	} else if (type == Long.class \|\| type == long.class) {
	return Long.valueOf(idCounter.getAndIncrement());
	} else if (type == UUID.class) {
	return UUID.randomUUID();
	}

	throw new UnsupportedOperationException("Automated key generation for type '" + type
	+ "' is not supported (caused on field '" + field + "').");
	}
	}

	private KeyElement getKeys(final T object) {
	return keyAccess.getKeyValues(object);
	}

	private KeyElement createSetAndGetKeys(final T object, boolean replaceKeys) throws DataStoreException {
	return keyAccess.createSetAndGetKeys(object, replaceKeys);
	}

	public static class DataStoreException extends ODataApplicationException {
	private static final long serialVersionUID = 42L;

	public DataStoreException(final String message) {
	this(message, null);
	}

	public DataStoreException(final String message, final Throwable cause) {
	super(message, Locale.ENGLISH, cause);
	}
	}
	}