/*
* Copyright 2011-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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://aws.amazon.com/apache2.0
*
* This file 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 com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
/**
* Reflection assistant for {@link DynamoDBMapper}
*/
class DynamoDBReflector {
/*
* Several caches for performance. Collectively, they can make this class
* over twice as fast.
*/
private final Map<Class<?>, Collection<Method>> getterCache = new HashMap<Class<?>, Collection<Method>>();
private final Map<Class<?>, Method> primaryHashKeyGetterCache = new HashMap<Class<?>, Method>();
private final Map<Class<?>, Method> primaryRangeKeyGetterCache = new HashMap<Class<?>, Method>();
/*
* All caches keyed by a Method use the getter for a particular mapped
* property
*/
private final Map<Method, Method> setterCache = new HashMap<Method, Method>();
private final Map<Method, String> attributeNameCache = new HashMap<Method, String>();
private final Map<Method, Boolean> versionAttributeGetterCache = new HashMap<Method, Boolean>();
private final Map<Method, Boolean> autoGeneratedKeyGetterCache = new HashMap<Method, Boolean>();
private final ReentrantReadWriteLock readWriteLockAttrName = new ReentrantReadWriteLock();
private final ReadLock readLockAttrName = readWriteLockAttrName.readLock();
private final WriteLock writeLockAttrName = readWriteLockAttrName.writeLock();
/**
* Returns the set of getter methods which are relevant when marshalling or
* unmarshalling an object.
*/
Collection<Method> getRelevantGetters(Class<?> clazz) {
synchronized (getterCache) {
if (!getterCache.containsKey(clazz)) {
List<Method> relevantGetters = findRelevantGetters(clazz);
getterCache.put(clazz, relevantGetters);
}
return getterCache.get(clazz);
}
}
static List<Method> findRelevantGetters(Class<?> clazz) {
List<Method> relevantGetters = new LinkedList<Method>();
for (Method m : clazz.getMethods()) {
if (isRelevantGetter(m)) {
relevantGetters.add(m);
}
}
return relevantGetters;
}
/**
* Returns whether the method given is a getter method we should serialize /
* deserialize to the service. The method must begin with "get" or "is",
* have no arguments, belong to a class that declares its table, and not be
* marked ignored.
*/
private static boolean isRelevantGetter(Method m) {
return (m.getName().startsWith("get") || m.getName().startsWith("is"))
&& m.getParameterTypes().length == 0
&& isDocumentType(m.getDeclaringClass())
&& !ReflectionUtils.getterOrFieldHasAnnotation(m, DynamoDBIgnore.class);
}
private static boolean isDocumentType(Class<?> clazz) {
return (clazz.getAnnotation(DynamoDBTable.class) != null)
|| (clazz.getAnnotation(DynamoDBDocument.class) != null);
}
/**
* Returns the annotated {@link DynamoDBRangeKey} getter for the class
* given, or null if the class doesn't have one.
*/
<T> Method getPrimaryRangeKeyGetter(Class<T> clazz) {
synchronized (primaryRangeKeyGetterCache) {
if (!primaryRangeKeyGetterCache.containsKey(clazz)) {
Method rangeKeyMethod = null;
for (Method method : getRelevantGetters(clazz)) {
if (method.getParameterTypes().length == 0
&& ReflectionUtils.getterOrFieldHasAnnotation(method,
DynamoDBRangeKey.class)) {
rangeKeyMethod = method;
break;
}
}
primaryRangeKeyGetterCache.put(clazz, rangeKeyMethod);
}
return primaryRangeKeyGetterCache.get(clazz);
}
}
/**
* Returns all annotated {@link DynamoDBHashKey} and
* {@link DynamoDBRangeKey} getters for the class given, throwing an
* exception if there isn't one. TODO: caching
*/
<T> Collection<Method> getPrimaryKeyGetters(Class<T> clazz) {
List<Method> keyGetters = new LinkedList<Method>();
for (Method getter : getRelevantGetters(clazz)) {
if (ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBHashKey.class)
|| ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBRangeKey.class)) {
keyGetters.add(getter);
}
}
return keyGetters;
}
/**
* Returns the annotated {@link DynamoDBHashKey} getter for the class given,
* throwing an exception if there isn't one.
*/
<T> Method getPrimaryHashKeyGetter(Class<T> clazz) {
Method hashKeyMethod;
synchronized (primaryHashKeyGetterCache) {
if (!primaryHashKeyGetterCache.containsKey(clazz)) {
for (Method method : getRelevantGetters(clazz)) {
if (method.getParameterTypes().length == 0
&& ReflectionUtils.getterOrFieldHasAnnotation(method,
DynamoDBHashKey.class)) {
primaryHashKeyGetterCache.put(clazz, method);
break;
}
}
}
hashKeyMethod = primaryHashKeyGetterCache.get(clazz);
}
if (hashKeyMethod == null) {
throw new DynamoDBMappingException(
"Public, zero-parameter hash key property must be annotated with "
+ DynamoDBHashKey.class);
}
return hashKeyMethod;
}
/**
* Returns the {@link DynamoDBTable} annotation of the class given, throwing
* a runtime exception if it isn't annotated.
*/
<T> DynamoDBTable getTable(Class<T> clazz) {
DynamoDBTable table = clazz.getAnnotation(DynamoDBTable.class);
if (table == null)
throw new DynamoDBMappingException("Class " + clazz + " must be annotated with "
+ DynamoDBTable.class);
return table;
}
/**
* Returns the attribute name corresponding to the given getter method.
*/
String getAttributeName(Method getter) {
String attributeName;
readLockAttrName.lock();
try {
attributeName = attributeNameCache.get(getter);
} finally {
readLockAttrName.unlock();
}
if (attributeName != null)
return attributeName;
DynamoDBHashKey hashKeyAnnotation = ReflectionUtils.getAnnotationFromGetterOrField(getter,
DynamoDBHashKey.class);
if (hashKeyAnnotation != null) {
attributeName = hashKeyAnnotation.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
DynamoDBIndexHashKey indexHashKey = ReflectionUtils.getAnnotationFromGetterOrField(getter,
DynamoDBIndexHashKey.class);
if (indexHashKey != null) {
attributeName = indexHashKey.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
DynamoDBRangeKey rangeKey = ReflectionUtils.getAnnotationFromGetterOrField(getter,
DynamoDBRangeKey.class);
if (rangeKey != null) {
attributeName = rangeKey.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
DynamoDBIndexRangeKey indexRangeKey = ReflectionUtils.getAnnotationFromGetterOrField(
getter, DynamoDBIndexRangeKey.class);
if (indexRangeKey != null) {
attributeName = indexRangeKey.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
DynamoDBAttribute attribute = ReflectionUtils.getAnnotationFromGetterOrField(getter,
DynamoDBAttribute.class);
if (attribute != null) {
attributeName = attribute.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
DynamoDBVersionAttribute version = ReflectionUtils.getAnnotationFromGetterOrField(getter,
DynamoDBVersionAttribute.class);
if (version != null) {
attributeName = version.attributeName();
if (attributeName != null && attributeName.length() > 0)
return cacheAttributeName(getter, attributeName);
}
// Default to the camel-cased field name of the getter method, inferred
// according to the Java naming convention.
attributeName = ReflectionUtils.getFieldNameByGetter(getter, true);
return cacheAttributeName(getter, attributeName);
}
private String cacheAttributeName(Method getter, String attributeName) {
writeLockAttrName.lock();
try {
attributeNameCache.put(getter, attributeName);
} finally {
writeLockAttrName.unlock();
}
return attributeName;
}
/**
* Returns the setter corresponding to the getter given, or null if no such
* setter exists.
*/
Method getSetter(Method getter) {
synchronized (setterCache) {
if (!setterCache.containsKey(getter)) {
String fieldName = ReflectionUtils.getFieldNameByGetter(getter, false);
String setterName = "set" + fieldName;
Method setter = null;
try {
setter = getter.getDeclaringClass().getMethod(setterName,
getter.getReturnType());
} catch (NoSuchMethodException e) {
throw new DynamoDBMappingException(
"Expected a public, one-argument method called " + setterName
+ " on class " + getter.getDeclaringClass(), e);
} catch (SecurityException e) {
throw new DynamoDBMappingException(
"No access to public, one-argument method called " + setterName
+ " on class " + getter.getDeclaringClass(), e);
}
setterCache.put(getter, setter);
}
return setterCache.get(getter);
}
}
/**
* Returns whether the method given is an annotated, no-args getter of a
* version attribute.
*/
boolean isVersionAttributeGetter(Method getter) {
synchronized (versionAttributeGetterCache) {
if (!versionAttributeGetterCache.containsKey(getter)) {
versionAttributeGetterCache.put(
getter,
getter.getName().startsWith("get")
&& getter.getParameterTypes().length == 0
&& ReflectionUtils.getterOrFieldHasAnnotation(getter,
DynamoDBVersionAttribute.class));
}
return versionAttributeGetterCache.get(getter);
}
}
/**
* Returns whether the method given is an assignable key getter.
*/
boolean isAssignableKey(Method getter) {
synchronized (autoGeneratedKeyGetterCache) {
if (!autoGeneratedKeyGetterCache.containsKey(getter)) {
autoGeneratedKeyGetterCache.put(
getter,
ReflectionUtils.getterOrFieldHasAnnotation(getter,
DynamoDBAutoGeneratedKey.class)
&& (ReflectionUtils.getterOrFieldHasAnnotation(getter,
DynamoDBHashKey.class) ||
ReflectionUtils.getterOrFieldHasAnnotation(getter,
DynamoDBRangeKey.class)));
}
return autoGeneratedKeyGetterCache.get(getter);
}
}
/**
* Returns the name of the primary hash key.
*/
String getPrimaryHashKeyName(Class<?> clazz) {
return getAttributeName(getPrimaryHashKeyGetter(clazz));
}
/**
* Returns the name of the primary range key, or null if the table does not
* one.
*/
String getPrimaryRangeKeyName(Class<?> clazz) {
Method primaryRangeKeyGetter = getPrimaryHashKeyGetter(clazz);
return primaryRangeKeyGetter == null ?
null
:
getAttributeName(getPrimaryRangeKeyGetter(clazz));
}
/**
* Returns true if and only if the specified class has declared a primary
* range key.
*/
boolean hasPrimaryRangeKey(Class<?> clazz) {
return getPrimaryRangeKeyGetter(clazz) != null;
}
}