/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.tinkerpop.gremlin.process.traversal.step.util;
import org.apache.commons.lang.ArrayUtils;
import org.apache.tinkerpop.gremlin.process.traversal.Traversal;
import org.apache.tinkerpop.gremlin.process.traversal.Traverser;
import org.apache.tinkerpop.gremlin.process.traversal.step.Scoping;
import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent;
import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil;
import org.apache.tinkerpop.gremlin.structure.Element;
import org.apache.tinkerpop.gremlin.structure.T;
import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Supplier;
/**
* The parameters held by a {@link Traversal}.
*
* @author Marko A. Rodriguez (http://markorodriguez.com)
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public final class Parameters implements Cloneable, Serializable {
private static final Object[] EMPTY_ARRAY = new Object[0];
private Map<Object, List<Object>> parameters = new HashMap<>();
private Set<String> referencedLabels = new HashSet<>();
/**
* A cached list of traversals that serve as parameter values. The list is cached on calls to
* {@link #set(TraversalParent, Object...)} because when the parameter map is large the cost of iterating it repeatedly on the
* high number of calls to {@link #getTraversals()} is great.
*/
private List<Traversal.Admin<?, ?>> traversals = new ArrayList<>();
/**
* Checks for existence of key in parameter set.
*
* @param key the key to check
* @return {@code true} if the key is present and {@code false} otherwise
*/
public boolean contains(final Object key) {
return this.parameters.containsKey(key);
}
/**
* Renames a key in the parameter set.
*
* @param oldKey the key to rename
* @param newKey the new name of the key
*/
public void rename(final Object oldKey, final Object newKey) {
this.parameters.put(newKey, this.parameters.remove(oldKey));
}
/**
* Gets the list of values for a key, while resolving the values of any parameters that are {@link Traversal}
* objects.
*/
public <S, E> List<E> get(final Traverser.Admin<S> traverser, final Object key, final Supplier<E> defaultValue) {
final List<E> values = (List<E>) this.parameters.get(key);
if (null == values) return Collections.singletonList(defaultValue.get());
final List<E> result = new ArrayList<>();
for (final Object value : values) {
result.add(value instanceof Traversal.Admin ? TraversalUtil.apply(traverser, (Traversal.Admin<S, E>) value) : (E) value);
}
return result;
}
/**
* Gets the value of a key and if that key isn't present returns the default value from the {@link Supplier}.
*
* @param key the key to retrieve
* @param defaultValue the default value generator
*/
public <E> List<E> get(final Object key, final Supplier<E> defaultValue) {
final List<E> list = (List<E>) this.parameters.get(key);
return (null == list) ? Collections.singletonList(defaultValue.get()) : list;
}
/**
* Remove a key from the parameter set.
*
* @param key the key to remove
* @return the value of the removed key
*/
public Object remove(final Object key) {
final List<Object> o = parameters.remove(key);
// once a key is removed, it's possible that the traversal/label cache will need to be regenerated
if (IteratorUtils.anyMatch(o.iterator(), p -> p instanceof Traversal.Admin)) {
traversals.clear();
traversals = new ArrayList<>();
for (final List<Object> list : this.parameters.values()) {
for (final Object object : list) {
if (object instanceof Traversal.Admin) {
final Traversal.Admin t = (Traversal.Admin) object;
addTraversal(t);
}
}
}
}
return o;
}
/**
* Gets the array of keys/values of the parameters while resolving parameter values that contain
* {@link Traversal} instances.
*/
public <S> Object[] getKeyValues(final Traverser.Admin<S> traverser, final Object... exceptKeys) {
if (this.parameters.isEmpty()) return EMPTY_ARRAY;
final List<Object> keyValues = new ArrayList<>();
for (final Map.Entry<Object, List<Object>> entry : this.parameters.entrySet()) {
if (!ArrayUtils.contains(exceptKeys, entry.getKey())) {
for (final Object value : entry.getValue()) {
keyValues.add(entry.getKey() instanceof Traversal.Admin ? TraversalUtil.apply(traverser, (Traversal.Admin<S, ?>) entry.getKey()) : entry.getKey());
keyValues.add(value instanceof Traversal.Admin ? TraversalUtil.apply(traverser, (Traversal.Admin<S, ?>) value) : value);
}
}
}
return keyValues.toArray(new Object[keyValues.size()]);
}
/**
* Gets an immutable set of the parameters without evaluating them in the context of a {@link Traverser} as
* is done in {@link #getKeyValues(Traverser.Admin, Object...)}.
*
* @param exceptKeys keys to not include in the returned {@link Map}
*/
public Map<Object, List<Object>> getRaw(final Object... exceptKeys) {
if (parameters.isEmpty()) return Collections.emptyMap();
final List<Object> exceptions = Arrays.asList(exceptKeys);
final Map<Object, List<Object>> raw = new HashMap<>();
for (Map.Entry<Object, List<Object>> entry : parameters.entrySet()) {
if (!exceptions.contains(entry.getKey())) raw.put(entry.getKey(), entry.getValue());
}
return Collections.unmodifiableMap(raw);
}
/**
* Set parameters given key/value pairs.
*/
public void set(final TraversalParent parent, final Object... keyValues) {
Parameters.legalPropertyKeyValueArray(keyValues);
for (int i = 0; i < keyValues.length; i = i + 2) {
if (keyValues[i + 1] != null) {
// track the list of traversals that are present so that elsewhere in Parameters there is no need
// to iterate all values to not find any. also grab available labels in traversal values
if (keyValues[i + 1] instanceof Traversal.Admin) {
final Traversal.Admin t = (Traversal.Admin) keyValues[i + 1];
addTraversal(t);
if (parent != null) parent.integrateChild(t);
}
List<Object> values = this.parameters.get(keyValues[i]);
if (null == values) {
values = new ArrayList<>();
values.add(keyValues[i + 1]);
this.parameters.put(keyValues[i], values);
} else {
values.add(keyValues[i + 1]);
}
}
}
}
/**
* Gets all the {@link Traversal.Admin} objects in the map of parameters.
*/
public <S, E> List<Traversal.Admin<S, E>> getTraversals() {
// stupid generics - just need to return "traversals"
return (List<Traversal.Admin<S, E>>) (Object) this.traversals;
}
/**
* Gets a list of all labels held in parameters that have a traversal as a value.
*/
public Set<String> getReferencedLabels() {
return referencedLabels;
}
public Parameters clone() {
try {
final Parameters clone = (Parameters) super.clone();
clone.parameters = new HashMap<>();
clone.traversals = new ArrayList<>();
for (final Map.Entry<Object, List<Object>> entry : this.parameters.entrySet()) {
final List<Object> values = new ArrayList<>();
for (final Object value : entry.getValue()) {
if (value instanceof Traversal.Admin) {
final Traversal.Admin<?, ?> traversalClone = ((Traversal.Admin) value).clone();
clone.traversals.add(traversalClone);
values.add(traversalClone);
} else
values.add(value);
}
if (entry.getKey() instanceof Traversal.Admin) {
final Traversal.Admin<?, ?> traversalClone = ((Traversal.Admin) entry.getKey()).clone();
clone.traversals.add(traversalClone);
clone.parameters.put(traversalClone, values);
} else
clone.parameters.put(entry.getKey(), values);
}
clone.referencedLabels = new HashSet<>(this.referencedLabels);
return clone;
} catch (final CloneNotSupportedException e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
public int hashCode() {
int result = 1;
for (final Map.Entry<Object, List<Object>> entry : this.parameters.entrySet()) {
result ^= entry.getKey().hashCode();
for (final Object value : entry.getValue()) {
result ^= Integer.rotateLeft(value.hashCode(), entry.getKey().hashCode());
}
}
return result;
}
public String toString() {
return this.parameters.toString();
}
private static void legalPropertyKeyValueArray(final Object... propertyKeyValues) throws IllegalArgumentException {
if (propertyKeyValues.length % 2 != 0)
throw Element.Exceptions.providedKeyValuesMustBeAMultipleOfTwo();
for (int i = 0; i < propertyKeyValues.length; i = i + 2) {
if (!(propertyKeyValues[i] instanceof String) && !(propertyKeyValues[i] instanceof T) && !(propertyKeyValues[i] instanceof Traversal))
throw new IllegalArgumentException("The provided key/value array must have a String, T, or Traversal on even array indices");
}
}
private void addTraversal(final Traversal.Admin t) {
this.traversals.add(t);
for (final Object ss : t.getSteps()) {
if (ss instanceof Scoping) {
for (String label : ((Scoping) ss).getScopeKeys()) {
this.referencedLabels.add(label);
}
}
}
}
}