/**
* Copyright (c) 2012-2014 "Indexia Technologies, ltd."
*
* This file is part of Antiquity.
*
* Antiquity is free software: you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package co.indexia.antiquity.graph;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMap.Builder;
import com.google.common.hash.HashCode;
import com.google.common.hash.HashFunction;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import com.tinkerpop.blueprints.Element;
import com.tinkerpop.blueprints.Graph;
import com.tinkerpop.blueprints.Vertex;
/**
* General read-only utils for a single {@link Element}.
*/
public class ElementUtils {
/**
* Get element's properties as an immutable java Map.
*
* @param element The element to get the properties for.
* @return a map of properties.
*/
public static Map<String, Object> getPropertiesAsMap(Element element) {
return getPropertiesAsMap(element, null);
}
/**
* Returns {@link Element}'s properties as an immutable map.
*
* @return An immutable map of the specified {@link Element} properties
* exlcuding the specified keys
*/
public static Map<String, Object> getPropertiesAsMap(Element element, Set<String> excludedKeys) {
Builder<String, Object> props = ImmutableMap.builder();
for (String key : element.getPropertyKeys()) {
if ((excludedKeys != null) && excludedKeys.contains(key)) {
continue;
}
props.put(key, element.getProperty(key));
}
return props.build();
}
/**
* <p>
* Calculate the private hash of an {@link Element}.
* </p>
*
* <p>
* The private hash contains only the properties of the {@link Element},
* without its associated elements.
* </p>
*
* <p>
* The hash is calculated based on SHA1 algorithm
* </p>
*
* TODO Handle arrays values properly.
*
* @param element The element to calculate the private hash for.
* @param excludedKeys the keys to exclude when hash is calculated.
* @return A string representation of the hash
* @see HashCode#toString()
*/
public static String calculateElementPrivateHash(Element element, Set<String> excludedKeys) {
Map<String, Object> props = ElementUtils.getPropertiesAsMap(element, excludedKeys);
Joiner.MapJoiner propsJoiner = Joiner.on('&').withKeyValueSeparator("=");
HashFunction hf = Hashing.sha1();
Hasher h = hf.newHasher();
//h.putString("[" + element.getId().toString() + "]");
h.putString(propsJoiner.join(props), Charset.defaultCharset());
return h.hash().toString();
}
/**
* Copy properties from one element to another.
*
* @param from element to copy properties from
* @param to element to copy properties to
* @param excludedKeys the keys that should be excluded from being copied.
*/
public static void copyProps(Element from, Element to, Set<String> excludedKeys) {
for (String k : from.getPropertyKeys()) {
if (excludedKeys != null && excludedKeys.contains(k)) {
continue;
}
to.setProperty(k, from.getProperty(k));
}
}
/**
* Get the specified {@link Element} properties as a string.
*
* @param withHeader if true the element's id will be printed in the first
* line.
* @param e The element to get the properties string for
* @return A formatted string containing the specified element's properties
*/
public static String getElementPropsAsString(Element e, boolean withHeader) {
StringBuilder elementPropsStr = new StringBuilder();
if (withHeader) {
elementPropsStr.append(e);
}
for (String key : e.getPropertyKeys()) {
elementPropsStr.append("\t").append(key).append("->").append(e.getProperty(key));
}
return elementPropsStr.toString();
}
/**
* Get a single element by key, value.
*
* @param graph The graph to get the element from
* @param key The key of the element
* @param value The value of the element
* @param clazz The class element type, can be Vertex | Edge.
* @return Found vertex that matches the specified criteria or null if not
* found.
* @throws IllegalStateException if multiple vertices found that matches the
* specified criteria
*/
@SuppressWarnings("unchecked")
public static <E extends Element> E getSingleElement(Graph graph, String key, Object value, Class<E> clazz) {
Iterable<?> it =
Vertex.class.isAssignableFrom(clazz) ? graph.query().has(key, value).vertices() : graph.query().has(key, value).edges();
Iterator<?> iter = it.iterator();
E e = null;
if (iter.hasNext()) {
e = (E) iter.next();
}
return e;
}
/**
* Get a single element.
*
* @param it iterable of elements.
* @param <E> must be of {@link Element} type.
* @return single element.
* @throws IllegalStateException if multiple elements found.
*/
@SuppressWarnings("unchecked")
public static <E extends Element> E getSingleElement(Iterable<E> it) {
Iterator<?> iter = it.iterator();
E e = null;
if (iter.hasNext()) {
e = (E) iter.next();
}
if (iter.hasNext()) throw new IllegalStateException(String.format("Multiple elements found."));
return e;
}
}
