Java tutorial
/* * #%L * ACS AEM Commons Bundle * %% * Copyright (C) 2017 Adobe * %% * 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. * #L% */ package com.adobe.acs.commons.synth.children; import org.apache.commons.collections.IteratorUtils; import org.apache.jackrabbit.JcrConstants; import org.apache.sling.api.resource.ModifiableValueMap; import org.apache.sling.api.resource.Resource; import org.apache.sling.api.resource.ResourceWrapper; import org.apache.sling.api.resource.ValueMap; import org.apache.sling.api.wrappers.ValueMapDecorator; import org.apache.sling.commons.json.JSONException; import org.apache.sling.commons.json.JSONObject; import org.joda.time.format.DateTimeFormatter; import org.joda.time.format.ISODateTimeFormat; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.jcr.RepositoryException; import java.io.Serializable; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.HashMap; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.List; import java.util.Map; import java.util.Set; import java.util.TreeSet; /** * Class to wrapper a real resource to facilitate the persistence of children resources in a property (serialized as * JSON). * * Can be used as follows... * * To write data: * * Resource real = resolve.getResource("/content/real"); * ChildrenAsPropertyResource wrapper = new ChildrenAsPropertyResource(real); * Resource child = wrapper.create("child-1", "nt:unstructured"); * ModifiableValueMap mvm = child.adaptTo(ModifiableValueMap.class); * mvm.put("prop-1", "some data"); * mvm.put("prop-2", Calendar.getInstance()); * wrapper.persist(); * resolver.commit(); * * To read data: * * Resource real = resolve.getResource("/content/real"); * ChildrenAsPropertyResource wrapper = new ChildrenAsPropertyResource(real); * for(Resource child : wrapper.getChildren()) { * child.getValueMap().get("prop-1", String.class); * } * */ public class ChildrenAsPropertyResource extends ResourceWrapper { private static final Logger log = LoggerFactory.getLogger(ChildrenAsPropertyResource.class); private static final String EMPTY_JSON = "{}"; private static final String DEFAULT_PROPERTY_NAME = "children"; private final Resource resource; private final String propertyName; private Map<String, Resource> lookupCache = null; private Set<Resource> orderedCache = null; private Comparator<Resource> comparator = null; public static final Comparator<Resource> RESOURCE_NAME_COMPARATOR = new ResourceNameComparator(); /** * ResourceWrapper that allows resource children to be modeled in data stored into a property using the default * property name of "children". * * @param resource the resource to store the children as properties on * @throws InvalidDataFormatException */ public ChildrenAsPropertyResource(Resource resource) throws InvalidDataFormatException { this(resource, DEFAULT_PROPERTY_NAME, null); } /** * ResourceWrapper that allows resource children to be modeled in data stored into a property. * * @param resource the resource to store the children as properties on * @param propertyName the property name to store the children as properties in */ public ChildrenAsPropertyResource(Resource resource, String propertyName) throws InvalidDataFormatException { this(resource, propertyName, null); } /** * ResourceWrapper that allows resource children to be modeled in data stored into a property. * * @param resource the resource to store the children as properties on * @param propertyName the property name to store the children as properties in * @param comparator the comparator used to order the serialized children * @throws InvalidDataFormatException */ public ChildrenAsPropertyResource(Resource resource, String propertyName, Comparator<Resource> comparator) throws InvalidDataFormatException { super(resource); this.resource = resource; this.propertyName = propertyName; this.comparator = comparator; if (this.comparator == null) { this.orderedCache = new LinkedHashSet<Resource>(); } else { this.orderedCache = new TreeSet<Resource>(this.comparator); } this.lookupCache = new HashMap<String, Resource>(); for (SyntheticChildAsPropertyResource r : this.deserialize()) { this.orderedCache.add(r); this.lookupCache.put(r.getName(), r); } } /** * {@inheritDoc} **/ @Override public final Iterator<Resource> listChildren() { return IteratorUtils.getIterator(this.orderedCache); } /** * {@inheritDoc} **/ @Override public final Iterable<Resource> getChildren() { return this.orderedCache; } /** * {@inheritDoc} **/ @Override public final Resource getChild(String name) { return this.lookupCache.get(name); } /** * {@inheritDoc} **/ @Override public final Resource getParent() { return this.resource; } public final Resource create(String name, String primaryType) throws RepositoryException { return create(name, primaryType, null); } public final Resource create(String name, String primaryType, Map<String, Object> data) throws RepositoryException { if (data == null) { data = new HashMap<String, Object>(); } if (data.containsKey(JcrConstants.JCR_PRIMARYTYPE) && primaryType != null) { data.put(JcrConstants.JCR_PRIMARYTYPE, primaryType); } final SyntheticChildAsPropertyResource child = new SyntheticChildAsPropertyResource(this.resource, name, data); if (this.lookupCache.containsKey(child.getName())) { log.info("Existing synthetic child [ {} ] overwritten", name); } this.lookupCache.put(child.getName(), child); this.orderedCache.add(child); return child; } /** * Deletes the named child. * * Requires subsequent call to persist(). * * @param name the child node name to delete * @throws RepositoryException */ public final void delete(String name) throws RepositoryException { if (this.lookupCache.containsKey(name)) { Resource tmp = this.lookupCache.get(name); this.orderedCache.remove(tmp); this.lookupCache.remove(name); } } /** * Delete all children. * * Requires subsequent call to persist(). * * @throws InvalidDataFormatException */ public final void deleteAll() throws InvalidDataFormatException { // Clear the caches; requires serialize if (this.comparator == null) { this.orderedCache = new LinkedHashSet<Resource>(); } else { this.orderedCache = new TreeSet<Resource>(this.comparator); } this.lookupCache = new HashMap<String, Resource>(); } /** * Persist changes to the underlying valuemap so they are available for persisting to the JCR. * * @throws RepositoryException */ public final void persist() throws RepositoryException { this.serialize(); } /** * Serializes all children data as JSON to the resource's propertyName. * * @throws InvalidDataFormatException */ private void serialize() throws InvalidDataFormatException { final long start = System.currentTimeMillis(); final ModifiableValueMap modifiableValueMap = this.resource.adaptTo(ModifiableValueMap.class); JSONObject childrenJSON = new JSONObject(); try { // Add the new entries to the JSON for (Resource childResource : this.orderedCache) { childrenJSON.put(childResource.getName(), this.serializeToJSON(childResource)); } if (childrenJSON.length() > 0) { // Persist the JSON back to the Node modifiableValueMap.put(this.propertyName, childrenJSON.toString()); } else { // Nothing to persist; delete the property modifiableValueMap.remove(this.propertyName); } log.debug("Persist operation for [ {} ] in [ {} ms ]", this.resource.getPath() + "/" + this.propertyName, System.currentTimeMillis() - start); } catch (JSONException e) { throw new InvalidDataFormatException(this.resource, this.propertyName, childrenJSON.toString()); } catch (NoSuchMethodException e) { throw new InvalidDataFormatException(this.resource, this.propertyName, childrenJSON.toString()); } catch (IllegalAccessException e) { throw new InvalidDataFormatException(this.resource, this.propertyName, childrenJSON.toString()); } catch (InvocationTargetException e) { throw new InvalidDataFormatException(this.resource, this.propertyName, childrenJSON.toString()); } } /** * Convert the serialized JSON data found in the node property to Resources. * * @return the list of children sorting using the comparator. * @throws InvalidDataFormatException */ private List<SyntheticChildAsPropertyResource> deserialize() throws InvalidDataFormatException { final long start = System.currentTimeMillis(); final String propertyData = this.resource.getValueMap().get(this.propertyName, EMPTY_JSON); List<SyntheticChildAsPropertyResource> resources; try { resources = deserializeToSyntheticChildResources(new JSONObject(propertyData)); } catch (JSONException e) { throw new InvalidDataFormatException(this.resource, this.propertyName, propertyData); } if (this.comparator != null) { Collections.sort(resources, this.comparator); } log.debug("Get operation for [ {} ] in [ {} ms ]", this.resource.getPath() + "/" + this.propertyName, System.currentTimeMillis() - start); return resources; } /** * Converts a list of SyntheticChildAsPropertyResource to their JSON representation, keeping the provided order. * * @param resourceToSerialize the resource to serialize to JSON. * @return the JSONObject representing the resources. * @throws JSONException */ protected final JSONObject serializeToJSON(final Resource resourceToSerialize) throws JSONException, IllegalAccessException, NoSuchMethodException, InvocationTargetException { final DateTimeFormatter dtf = ISODateTimeFormat.dateTime(); final Map<String, Object> serializedData = new HashMap<String, Object>(); for (Map.Entry<String, Object> entry : resourceToSerialize.getValueMap().entrySet()) { if (entry.getValue() instanceof Calendar) { final Calendar cal = (Calendar) entry.getValue(); serializedData.put(entry.getKey(), dtf.print(cal.getTimeInMillis())); } else if (entry.getValue() instanceof Date) { final Date date = (Date) entry.getValue(); serializedData.put(entry.getKey(), dtf.print(date.getTime())); } else { serializedData.put(entry.getKey(), entry.getValue()); } } return new JSONObject(serializedData); } /** * Converts a JSONObject to the list of SyntheticChildAsPropertyResources. * * @param jsonObject the JSONObject to deserialize. * @return the list of SyntheticChildAsPropertyResources the jsonObject represents. * @throws JSONException */ protected final List<SyntheticChildAsPropertyResource> deserializeToSyntheticChildResources( JSONObject jsonObject) throws JSONException { final List<SyntheticChildAsPropertyResource> resources = new ArrayList<SyntheticChildAsPropertyResource>(); final Iterator<String> keys = jsonObject.keys(); while (keys.hasNext()) { final String nodeName = keys.next(); JSONObject entryJSON = jsonObject.optJSONObject(nodeName); if (entryJSON == null) { continue; } final ValueMap properties = new ValueMapDecorator(new HashMap<String, Object>()); final Iterator<String> propertyNames = entryJSON.keys(); while (propertyNames.hasNext()) { final String propName = propertyNames.next(); properties.put(propName, entryJSON.optString(propName)); } resources.add(new SyntheticChildAsPropertyResource(this.getParent(), nodeName, properties)); } return resources; } /** * Sort by resource name ascending (resource.getName()). */ private static final class ResourceNameComparator implements Comparator<Resource>, Serializable { private static final long serialVersionUID = 0L; @Override public int compare(final Resource o1, final Resource o2) { return o1.getName().compareTo(o2.getName().toString()); } } }