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Fixed #99: Generic and typesafe DocumentAccessor
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Signed-off-by: Henrik Lundgren <carl.henrik.lundgren@gmail.com>
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Henrik Lundgren committed May 24, 2011
1 parent 0686a63 commit 3624f0e
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Showing 3 changed files with 71 additions and 62 deletions.
2 changes: 2 additions & 0 deletions .gitignore
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Expand Up @@ -15,3 +15,5 @@ local.properties

# CDT-specific
.cproject

/org.ektorp.spring/target/
11 changes: 6 additions & 5 deletions org.ektorp/src/main/java/org/ektorp/util/DocumentAccessor.java
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Expand Up @@ -2,20 +2,21 @@
/**
* Interface for accessing id and rev fields in a document of unknown type.
* @author henrik lundgren
* @author Pascal Gélinas (issue 99)
*
*/
public interface DocumentAccessor {
public interface DocumentAccessor<T> {
/**
* @return true if document type's id field can be mutated.
*/
boolean hasIdMutator();

String getId(Object o);
String getId(T o);

void setId(Object o, String id);
void setId(T o, String id);

String getRevision(Object o);
String getRevision(T o);

void setRevision(Object o, String rev);
void setRevision(T o, String rev);

}
120 changes: 63 additions & 57 deletions org.ektorp/src/main/java/org/ektorp/util/Documents.java
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Expand Up @@ -23,33 +23,36 @@
*
* @author henrik lundgren
* @author bjohnson.professional
* @author Pascal Gélinas (issue 99)
*
*/
public final class Documents {

private final static Logger LOG = LoggerFactory.getLogger(Documents.class);
private final static ConcurrentMap<Class<?>, DocumentAccessor> accessors = new ConcurrentHashMap<Class<?>, DocumentAccessor>();
private final static ConcurrentMap<Class<?>, DocumentAccessor<?>> accessors = new ConcurrentHashMap<Class<?>, DocumentAccessor<?>>();
private static final String ID_FIELD_NAME = "_id";
private static final String REV_FIELD_NAME = "_rev";

static {
// MapAccessor is an unchecked implementation of DocumentAccessor and as such we cannot guarantee proper type safety.
accessors.put(Map.class, new MapAccessor());
accessors.put(ObjectNode.class, new ObjectNodeAccessor());
putAccessor(ObjectNode.class, new ObjectNodeAccessor());
}

/**
* Used to register a custom DocumentAccessor for a particular class.
* Any existing accessor for the class will be overridden.
* @param documentType
* @param accessor
*/
public static void registerAccessor(Class<?> documentType, DocumentAccessor accessor) {
public static <T> void registerAccessor(Class<? extends T> documentType, DocumentAccessor<T> accessor) {
Assert.notNull(documentType, "documentType may not be null");
Assert.notNull(accessor, "accessor may not be null");
if (accessors.containsKey(documentType)) {
DocumentAccessor existing = accessors.get(documentType);
DocumentAccessor<T> existing = getAccessor(documentType);
LOG.warn(String.format("DocumentAccessor for class %s already exists: %s will be overridden by %s", documentType, existing.getClass(), accessor.getClass()));
}
accessors.put(documentType, accessor);
putAccessor(documentType, accessor);
LOG.debug("Registered document accessor: {} for class: {}", accessor.getClass(), documentType);
}

Expand All @@ -65,7 +68,7 @@ public static String getId(Object document) {
* @param id
*/
public static void setId(Object document, String id) {
DocumentAccessor d = getAccessor(document);
DocumentAccessor<? super Object> d = getAccessor(document);
if (d.hasIdMutator()) {
d.setId(document, id);
}
Expand All @@ -82,35 +85,46 @@ public static void setRevision(Object document, String rev) {
public static boolean isNew(Object document) {
return getRevision(document) == null;
}

private static <T> void putAccessor(Class<? extends T> documentType, DocumentAccessor<T> accessor){
accessors.put(documentType, accessor);
}

// Unchecked cast is ok here since we ensure proper type safety during put operation.
@SuppressWarnings("unchecked")
private static <E, T extends E> DocumentAccessor<E> getAccessor(Class<T> documentType){
return (DocumentAccessor<E>) accessors.get(documentType);
}

private static DocumentAccessor getAccessor(Object document) {
Class<?> clazz = document.getClass();
DocumentAccessor accessor = accessors.get(clazz);
private static <T> DocumentAccessor<? super T> getAccessor(T document) {
@SuppressWarnings("unchecked")
Class<? extends T> clazz = (Class< ? extends T>) document.getClass();
DocumentAccessor<? super T> accessor = getAccessor(clazz);
if (accessor == null) {
if (document instanceof Map<?, ?>) {
accessor = accessors.get(Map.class);
accessors.put(clazz, accessor);
accessor = getAccessor(Map.class);
putAccessor(clazz, accessor);
} else if (document instanceof ObjectNode) {
accessor = accessors.get(ObjectNode.class);
accessors.put(clazz, accessor);
accessor = getAccessor(ObjectNode.class);
putAccessor(clazz, accessor);
} else {
try {
accessor = new AnnotatedMethodAccessor(clazz);
accessor = new AnnotatedMethodAccessor<T>(clazz);
} catch (InvalidDocumentException eAnnotatedMethod) {
try {
accessor = new AnnotatedFieldAccessor(clazz);
accessor = new AnnotatedFieldAccessor<T>(clazz);
} catch (InvalidDocumentException eAnnotatedField) {
accessor = new MethodAccessor(clazz);
accessor = new MethodAccessor<T>(clazz);
}
}
accessors.putIfAbsent(clazz, accessor);
accessor = accessors.get(clazz);
accessor = getAccessor(clazz);
}
}
return accessor;
}

private static class MethodAccessor implements DocumentAccessor {
private static class MethodAccessor<T> implements DocumentAccessor<T> {

private final Class<?>[] NO_PARAMS = new Class<?>[0];
private final Object[] NO_ARGS = new Object[0];
Expand All @@ -120,7 +134,7 @@ private static class MethodAccessor implements DocumentAccessor {
Method revisionAccessor;
Method revisionMutator;

MethodAccessor(Class<?> clazz) {
MethodAccessor(Class<? extends T> clazz) {
try {
idAccessor = resolveIdAccessor(clazz);
assertMethodFound(clazz, idAccessor, "id accessor");
Expand Down Expand Up @@ -190,7 +204,7 @@ protected Method resolveRevMutator(Class<?> clazz) throws Exception {
*
* @see org.ektorp.util.DocumentAccessor#getId(java.lang.Object)
*/
public String getId(Object o) {
public String getId(T o) {
try {
return (String) idAccessor.invoke(o, NO_ARGS);
} catch (Exception e) {
Expand All @@ -204,7 +218,7 @@ public String getId(Object o) {
* @see org.ektorp.util.DocumentAccessor#setId(java.lang.Object,
* java.lang.String)
*/
public void setId(Object o, String id) {
public void setId(T o, String id) {
try {
idMutator.invoke(o, id);
} catch (Exception e) {
Expand All @@ -217,7 +231,7 @@ public void setId(Object o, String id) {
*
* @see org.ektorp.util.DocumentAccessor#getRevision(java.lang.Object)
*/
public String getRevision(Object o) {
public String getRevision(T o) {
try {
return (String) revisionAccessor.invoke(o, NO_ARGS);
} catch (Exception e) {
Expand All @@ -231,7 +245,7 @@ public String getRevision(Object o) {
* @see org.ektorp.util.DocumentAccessor#setRevision(java.lang.Object,
* java.lang.String)
*/
public void setRevision(Object o, String rev) {
public void setRevision(T o, String rev) {
try {
revisionMutator.invoke(o, rev);
} catch (Exception e) {
Expand All @@ -240,9 +254,9 @@ public void setRevision(Object o, String rev) {
}
}

private final static class AnnotatedMethodAccessor extends MethodAccessor {
private final static class AnnotatedMethodAccessor<T> extends MethodAccessor<T> {

AnnotatedMethodAccessor(Class<?> clazz) {
AnnotatedMethodAccessor(Class<? extends T> clazz) {
super(clazz);
}

Expand Down Expand Up @@ -283,14 +297,14 @@ private Method findAnnotatedMethod(Class<?> clazz,
}
}

private final static class AnnotatedFieldAccessor implements DocumentAccessor {
private final static class AnnotatedFieldAccessor<T> implements DocumentAccessor<T> {

Field idAccessor;
Field idMutator;
Field revisionAccessor;
Field revisionMutator;

AnnotatedFieldAccessor(Class<?> clazz) {
AnnotatedFieldAccessor(Class<? extends T> clazz) {
try {
idAccessor = resolveIdAccessor(clazz);
assertFieldFound(clazz, idAccessor, "id accessor");
Expand Down Expand Up @@ -369,7 +383,7 @@ private Field findAnnotatedField(Class<?> clazz,
*
* @see org.ektorp.util.DocumentAccessor#getId(java.lang.Object)
*/
public String getId(Object o) {
public String getId(T o) {
try {
return (String) idAccessor.get(o);
} catch (Exception e) {
Expand All @@ -383,7 +397,7 @@ public String getId(Object o) {
* @see org.ektorp.util.DocumentAccessor#setId(java.lang.Object,
* java.lang.String)
*/
public void setId(Object o, String id) {
public void setId(T o, String id) {
try {
idMutator.set(o, id);
} catch (Exception e) {
Expand All @@ -396,7 +410,7 @@ public void setId(Object o, String id) {
*
* @see org.ektorp.util.DocumentAccessor#getRevision(java.lang.Object)
*/
public String getRevision(Object o) {
public String getRevision(T o) {
try {
return (String) revisionAccessor.get(o);
} catch (Exception e) {
Expand All @@ -410,7 +424,7 @@ public String getRevision(Object o) {
* @see org.ektorp.util.DocumentAccessor#setRevision(java.lang.Object,
* java.lang.String)
*/
public void setRevision(Object o, String rev) {
public void setRevision(T o, String rev) {
try {
revisionMutator.set(o, rev);
} catch (Exception e) {
Expand All @@ -419,63 +433,55 @@ public void setRevision(Object o, String rev) {
}
}

private final static class MapAccessor implements DocumentAccessor {
private final static class MapAccessor implements DocumentAccessor<Map<String, String>> {

public String getId(Object o) {
return cast(o).get(ID_FIELD_NAME);
public String getId(Map<String, String> o) {
return o.get(ID_FIELD_NAME);
}

public String getRevision(Object o) {
return cast(o).get(REV_FIELD_NAME);
public String getRevision(Map<String, String> o) {
return o.get(REV_FIELD_NAME);
}

public boolean hasIdMutator() {
return true;
}

public void setId(Object o, String id) {
cast(o).put(ID_FIELD_NAME, id);
public void setId(Map<String, String> o, String id) {
o.put(ID_FIELD_NAME, id);
}

public void setRevision(Object o, String rev) {
cast(o).put(REV_FIELD_NAME, rev);
}

@SuppressWarnings("unchecked")
private Map<String, String> cast(Object o) {
return (Map<String, String>) o;
public void setRevision(Map<String, String> o, String rev) {
o.put(REV_FIELD_NAME, rev);
}

}

private final static class ObjectNodeAccessor implements DocumentAccessor {
private final static class ObjectNodeAccessor implements DocumentAccessor<ObjectNode> {

public boolean hasIdMutator() {
return true;
}

public String getId(Object o) {
public String getId(ObjectNode o) {
return getFieldValue(o, ID_FIELD_NAME);
}

public void setId(Object o, String id) {
public void setId(ObjectNode o, String id) {
setField(o, ID_FIELD_NAME, id);
}

public String getRevision(Object o) {
public String getRevision(ObjectNode o) {
return getFieldValue(o, REV_FIELD_NAME);
}

public void setRevision(Object o, String rev) {
public void setRevision(ObjectNode o, String rev) {
setField(o, REV_FIELD_NAME, rev);
}

private ObjectNode cast(Object o) {
return (ObjectNode) o;
}

private String getFieldValue(Object target, String fieldName) {
JsonNode field = cast(target).get(fieldName);
private String getFieldValue(ObjectNode target, String fieldName) {
JsonNode field = target.get(fieldName);
if (field == null) {
return null;
}
Expand All @@ -486,8 +492,8 @@ private String getFieldValue(Object target, String fieldName) {
return field.getTextValue();
}

private void setField(Object target, String fieldName, String fieldValue) {
cast(target).put(fieldName, fieldValue);
private void setField(ObjectNode target, String fieldName, String fieldValue) {
target.put(fieldName, fieldValue);
}

}
Expand Down

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