diff options
Diffstat (limited to 'src/main/java/com/amazon/carbonado/spi/LobEngineTrigger.java')
| -rw-r--r-- | src/main/java/com/amazon/carbonado/spi/LobEngineTrigger.java | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/main/java/com/amazon/carbonado/spi/LobEngineTrigger.java b/src/main/java/com/amazon/carbonado/spi/LobEngineTrigger.java new file mode 100644 index 0000000..2e42d8e --- /dev/null +++ b/src/main/java/com/amazon/carbonado/spi/LobEngineTrigger.java @@ -0,0 +1,181 @@ +/*
+ * Copyright 2006 Amazon Technologies, Inc. or its affiliates.
+ * Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
+ * of Amazon Technologies, 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://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 com.amazon.carbonado.spi;
+
+import java.util.List;
+
+import org.cojen.util.BeanPropertyAccessor;
+
+import com.amazon.carbonado.FetchException;
+import com.amazon.carbonado.PersistException;
+import com.amazon.carbonado.Storable;
+import com.amazon.carbonado.Trigger;
+
+import com.amazon.carbonado.lob.Lob;
+
+/**
+ *
+ *
+ * @author Brian S O'Neill
+ * @see LobEngine
+ */
+class LobEngineTrigger<S extends Storable> extends Trigger<S> {
+ final LobEngine mEngine;
+ private final int mBlockSize;
+ private final BeanPropertyAccessor mAccessor;
+ private final LobProperty<Lob>[] mLobProperties;
+
+ LobEngineTrigger(LobEngine engine, Class<S> type, int blockSize,
+ List<LobProperty<?>> lobProperties)
+ {
+ mEngine = engine;
+ mAccessor = BeanPropertyAccessor.forClass(type);
+ mBlockSize = blockSize;
+
+ mLobProperties = new LobProperty[lobProperties.size()];
+ lobProperties.toArray(mLobProperties);
+ }
+
+ // Returns user specified Lob values
+ public Object beforeInsert(S storable) throws PersistException {
+ // Capture user lob values for later and replace with new locators.
+ int length = mLobProperties.length;
+ Object[] userLobs = new Object[length];
+ for (int i=0; i<length; i++) {
+ LobProperty<Lob> prop = mLobProperties[i];
+ Object userLob = mAccessor.getPropertyValue(storable, prop.mName);
+ userLobs[i] = userLob;
+ if (userLob != null) {
+ Object lob = prop.createNewLob(mBlockSize);
+ mAccessor.setPropertyValue(storable, prop.mName, lob);
+ }
+ }
+ return userLobs;
+ }
+
+ public void afterInsert(S storable, Object state) throws PersistException {
+ // Save user lob value contents into new lobs.
+ Object[] userLobs = (Object[]) state;
+ int length = mLobProperties.length;
+ for (int i=0; i<length; i++) {
+ Object userLob = userLobs[i];
+ if (userLob != null) {
+ LobProperty<Lob> prop = mLobProperties[i];
+ Lob lob = (Lob) mAccessor.getPropertyValue(storable, prop.mName);
+ prop.setLobValue(mEngine.getLocator(lob), (Lob) userLob);
+ }
+ }
+ }
+
+ public void failedInsert(S storable, Object state) {
+ unreplaceLobs(storable, state);
+ }
+
+ public Object beforeUpdate(S storable) throws PersistException {
+ // For each dirty lob property, capture it in case update fails. All
+ // lob updates are made in this method.
+
+ int length = mLobProperties.length;
+ Object[] userLobs = new Object[length];
+ S existing = null;
+
+ for (int i=0; i<length; i++) {
+ LobProperty<Lob> prop = mLobProperties[i];
+ if (!storable.isPropertyDirty(prop.mName)) {
+ continue;
+ }
+
+ try {
+ if (existing == null && (existing = loadExisting(storable)) == null) {
+ // Update will fail so don't touch lobs.
+ return null;
+ }
+ } catch (FetchException e) {
+ throw e.toPersistException();
+ }
+
+ Object userLob = mAccessor.getPropertyValue(storable, prop.mName);
+ userLobs[i] = userLob;
+ Lob existingLob = (Lob) mAccessor.getPropertyValue(existing, prop.mName);
+ if (userLob == null) {
+ if (existingLob != null) {
+ // User is setting existing lob to null, so delete it.
+ mEngine.deleteLob(existingLob);
+ }
+ } else {
+ if (existingLob == null) {
+ // User is setting a lob that has no locator yet, so make one.
+ existingLob = prop.createNewLob(mBlockSize);
+ }
+ prop.setLobValue(mEngine.getLocator(existingLob), (Lob) userLob);
+ mAccessor.setPropertyValue(storable, prop.mName, existingLob);
+ }
+ }
+
+ return userLobs;
+ }
+
+ public void failedUpdate(S storable, Object state) {
+ unreplaceLobs(storable, state);
+ }
+
+ // Returns existing Storable or null
+ public Object beforeDelete(S storable) throws PersistException {
+ S existing = (S) storable.copy();
+ try {
+ if (!existing.tryLoad()) {
+ existing = null;
+ }
+ return existing;
+ } catch (FetchException e) {
+ throw e.toPersistException();
+ }
+ }
+
+ public void afterDelete(S storable, Object existing) throws PersistException {
+ if (existing != null) {
+ // After successful delete of master storable, delete all the lobs.
+ for (LobProperty<Lob> prop : mLobProperties) {
+ Lob lob = (Lob) mAccessor.getPropertyValue(existing, prop.mName);
+ mEngine.deleteLob(lob);
+ }
+ }
+ }
+
+ private S loadExisting(S storable) throws FetchException {
+ S existing = (S) storable.copy();
+ if (!existing.tryLoad()) {
+ return null;
+ }
+ return existing;
+ }
+
+ private void unreplaceLobs(S storable, Object state) {
+ if (state != null) {
+ Object[] userLobs = (Object[]) state;
+ int length = mLobProperties.length;
+ for (int i=0; i<length; i++) {
+ Object userLob = userLobs[i];
+ if (userLob != null) {
+ mAccessor.setPropertyValue(storable, mLobProperties[i].mName, userLob);
+ }
+ }
+ }
+ }
+}
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