Java tutorial
/* * Copyright: Almende B.V. (2014), Rotterdam, The Netherlands * License: The Apache Software License, Version 2.0 */ package com.almende.eve.state.couch; import java.util.HashSet; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import java.util.logging.Level; import java.util.logging.Logger; import org.ektorp.CouchDbConnector; import org.ektorp.UpdateConflictException; import com.almende.eve.state.AbstractState; import com.almende.eve.state.State; import com.almende.eve.state.couch.CouchStateBuilder.CouchStateProvider; import com.fasterxml.jackson.annotation.JsonInclude; import com.fasterxml.jackson.annotation.JsonInclude.Include; import com.fasterxml.jackson.annotation.JsonProperty; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.node.NullNode; import com.fasterxml.jackson.databind.node.ObjectNode; /** * The Class CouchState. */ public class CouchState extends AbstractState<JsonNode> implements State { private static final Logger LOG = Logger.getLogger(CouchState.class.getName()); private String revision = null; private Map<String, JsonNode> properties = new ConcurrentHashMap<String, JsonNode>(); private CouchDbConnector db = null; /** * Instantiates a new couch state. */ public CouchState() { } /** * Instantiates a new couch state. * * @param id * the id * @param db * the db * @param service * the service * @param params * the params */ public CouchState(final String id, final CouchDbConnector db, final CouchStateProvider service, final ObjectNode params) { super(id, service, params); this.db = db; } /** * Read. */ private void read() { try { synchronized (properties) { final CouchState state = db.get(CouchState.class, getId()); if (state != null) { revision = state.revision; properties.clear(); properties.putAll(state.properties); } } } catch (final org.ektorp.DocumentNotFoundException e) { } } /* * (non-Javadoc) * * @see com.almende.eve.state.AbstractState#locPut(java.lang.String, * com.fasterxml.jackson.databind.JsonNode) */ @Override public JsonNode locPut(final String key, final JsonNode value) { final String ckey = couchify(key); JsonNode result = null; try { synchronized (properties) { result = properties.put(ckey, value); } db.update(this); } catch (final UpdateConflictException uce) { read(); return locPut(ckey, value); } catch (final Exception e) { LOG.log(Level.WARNING, "Failed to store property", e); } return result; } /* * (non-Javadoc) * * @see * com.almende.eve.state.AbstractState#locPutIfUnchanged(java.lang.String, * com.fasterxml.jackson.databind.JsonNode, * com.fasterxml.jackson.databind.JsonNode) */ @Override public boolean locPutIfUnchanged(final String key, final JsonNode newVal, JsonNode oldVal) { final String ckey = couchify(key); boolean result = false; try { JsonNode cur = NullNode.getInstance(); if (properties.containsKey(ckey)) { cur = properties.get(ckey); } if (oldVal == null) { oldVal = NullNode.getInstance(); } // Poor mans equality as some Numbers are compared incorrectly: e.g. // IntNode versus LongNode if (oldVal.equals(cur) || oldVal.toString().equals(cur.toString())) { synchronized (properties) { properties.put(ckey, newVal); } db.update(this); result = true; } } catch (final UpdateConflictException uce) { read(); return locPutIfUnchanged(ckey, newVal, oldVal); } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /* * (non-Javadoc) * * @see com.almende.eve.state.State#remove(java.lang.String) */ @Override public Object remove(final String key) { final String ckey = couchify(key); Object result = null; try { synchronized (properties) { result = properties.remove(ckey); } db.update(this); } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /* * (non-Javadoc) * * @see com.almende.eve.state.State#containsKey(java.lang.String) */ @Override public boolean containsKey(final String key) { final String ckey = couchify(key); boolean result = false; try { result = properties.containsKey(ckey); if (result == false) { read(); result = properties.containsKey(ckey); } } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /* * (non-Javadoc) * * @see com.almende.eve.state.State#keySet() */ @Override public Set<String> keySet() { final Set<String> result = new HashSet<String>(); Set<String> keys = null; try { keys = new HashSet<String>(properties.keySet()); for (final String key : keys) { result.add(decouchify(key)); } } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /* * (non-Javadoc) * * @see com.almende.eve.state.State#clear() */ @Override public void clear() { try { synchronized (properties) { properties.clear(); } db.update(this); } catch (final Exception e) { LOG.log(Level.WARNING, "Failed clearing state", e); } } /* * (non-Javadoc) * * @see com.almende.eve.state.State#size() */ @Override public int size() { int result = -1; try { result = properties.size(); } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /* * (non-Javadoc) * * @see com.almende.eve.state.AbstractState#get(java.lang.String) */ @Override public JsonNode get(String key) { key = couchify(key); JsonNode result = null; try { result = properties.get(key); if (result == null) { read(); result = properties.get(key); } } catch (final Exception e) { LOG.log(Level.WARNING, "", e); } return result; } /** * Gets the id. * * @return the id */ @Override @JsonProperty("_id") public String getId() { return super.getId(); }; /** * Sets the id. * * @param id * the new id */ @Override @JsonProperty("_id") public void setId(final String id) { super.setId(id); } /** * Gets the revision. * * @return the revision */ @JsonProperty("_rev") @JsonInclude(Include.NON_NULL) public String getRevision() { return revision; } /** * Sets the revision. * * @param revision * the new revision */ @JsonProperty("_rev") public void setRevision(final String revision) { this.revision = revision; } /** * Gets the properties. * * @return the properties */ public Map<String, JsonNode> getProperties() { return properties; } /** * Sets the properties. * * @param properties * the properties */ public void setProperties(final Map<String, JsonNode> properties) { this.properties = properties; } /** * Sets the db. * * @param db * the new db */ public void setDb(final CouchDbConnector db) { this.db = db; } /** * Check the key if it starts with a _ * Add a prefix if this is the case, because _ properties are reserved. * * @param key * the key * @return prefixed key (if necessary) */ private String couchify(final String key) { if (key.startsWith("_")) { return "cdb" + key; } return key; } /** * Check the key if it starts with a _ * Add a prefix if this is the case, because _ properties are reserved. * * @param key * the key * @return prefixed key (if necessary) */ private String decouchify(final String key) { if (key.startsWith("cdb_")) { return key.replaceFirst("cdb_", "_"); } return key; } }