/*
* 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.flink.api.common.operators.util;
import org.apache.flink.annotation.Internal;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
/**
* Immutable unordered collection of fields IDs.
*/
@Internal
public class FieldSet implements Iterable<Integer> {
public static final FieldSet EMPTY_SET = new FieldSet();
protected final Collection<Integer> collection;
// --------------------------------------------------------------------------------------------
/**
* Creates a new empty set of fields.
*/
public FieldSet() {
this.collection = Collections.emptySet();
}
/**
* Creates a set with one field.
*
* @param fieldID The id of the field.
*/
public FieldSet(Integer fieldID) {
if (fieldID == null) {
throw new IllegalArgumentException("Field ID must not be null.");
}
this.collection = Collections.singleton(fieldID);
}
/**
* Creates a set with the given fields.
*
* @param fieldIDs The IDs of the fields.
*/
public FieldSet(int... fieldIDs) {
if (fieldIDs == null || fieldIDs.length == 0) {
this.collection = Collections.emptySet();
} else {
HashSet<Integer> set = new HashSet<Integer>(2 * fieldIDs.length);
for (int i = 0; i < fieldIDs.length; i++) {
set.add(fieldIDs[i]);
}
this.collection = Collections.unmodifiableSet(set);
}
}
/**
* Creates a set with the given fields.
*
* @param fieldIDs The IDs of the fields.
*/
public FieldSet(int[] fieldIDs, boolean marker) {
if (fieldIDs == null || fieldIDs.length == 0) {
this.collection = Collections.emptySet();
} else {
HashSet<Integer> set = new HashSet<Integer>(2 * fieldIDs.length);
for (int i = 0; i < fieldIDs.length; i++) {
set.add(fieldIDs[i]);
}
this.collection = Collections.unmodifiableSet(set);
}
}
protected FieldSet(Collection<Integer> fields) {
this.collection = fields;
}
/**
* @param fieldSet The first part of the new set, NOT NULL!
* @param fieldID The ID to be added, NOT NULL!
*/
private FieldSet(FieldSet fieldSet, Integer fieldID) {
if (fieldSet.size() == 0) {
this.collection = Collections.singleton(fieldID);
}
else {
HashSet<Integer> set = new HashSet<Integer>(2 * (fieldSet.collection.size() + 1));
set.addAll(fieldSet.collection);
set.add(fieldID);
this.collection = Collections.unmodifiableSet(set);
}
}
private FieldSet(FieldSet fieldSet, int... fieldIDs) {
if (fieldIDs == null || fieldIDs.length == 0) {
this.collection = fieldSet.collection;
} else {
HashSet<Integer> set = new HashSet<Integer>(2 * (fieldSet.collection.size() + fieldIDs.length));
set.addAll(fieldSet.collection);
for (int i = 0; i < fieldIDs.length; i++) {
set.add(fieldIDs[i]);
}
this.collection = Collections.unmodifiableSet(set);
}
}
private FieldSet(FieldSet fieldSet1, FieldSet fieldSet2) {
if (fieldSet2.size() == 0) {
this.collection = fieldSet1.collection;
}
else if (fieldSet1.size() == 0) {
this.collection = fieldSet2.collection;
}
else {
HashSet<Integer> set = new HashSet<Integer>(2 * (fieldSet1.size() + fieldSet2.size()));
set.addAll(fieldSet1.collection);
set.addAll(fieldSet2.collection);
this.collection = Collections.unmodifiableSet(set);
}
}
// --------------------------------------------------------------------------------------------
public FieldSet addField(Integer fieldID) {
if (fieldID == null) {
throw new IllegalArgumentException("Field ID must not be null.");
}
return new FieldSet(this, fieldID);
}
public FieldSet addFields(int... fieldIDs) {
return new FieldSet(this, fieldIDs);
}
public FieldSet addFields(FieldSet set) {
if (set == null) {
throw new IllegalArgumentException("FieldSet to add must not be null.");
}
if (set.size() == 0) {
return this;
}
else if (this.size() == 0) {
return set;
}
else {
return new FieldSet(this, set);
}
}
public boolean contains(Integer columnIndex) {
return this.collection.contains(columnIndex);
}
public int size() {
return this.collection.size();
}
@Override
public Iterator<Integer> iterator() {
return this.collection.iterator();
}
/**
* Turns the FieldSet into an ordered FieldList.
*
* @return An ordered FieldList.
*/
public FieldList toFieldList() {
int[] pos = toArray();
Arrays.sort(pos);
return new FieldList(pos);
}
/**
* Transforms the field set into an array of field IDs. Whether the IDs are ordered
* or unordered depends on the specific subclass of the field set.
*
* @return An array of all contained field IDs.
*/
public int[] toArray() {
int[] a = new int[this.collection.size()];
int i = 0;
for (int col : this.collection) {
a[i++] = col;
}
return a;
}
// --------------------------------------------------------------------------------------------
/**
* Checks if the given set of fields is a valid subset of this set of fields. For unordered
* sets, this is the case if all of the given set's fields are also part of this field.
* <p>
* Subclasses that describe field sets where the field order matters must override this method
* to implement a field ordering sensitive check.
*
* @param set The set that is a candidate subset.
* @return True, if the given set is a subset of this set, false otherwise.
*/
public boolean isValidSubset(FieldSet set) {
if (set.size() > size()) {
return false;
}
for (Integer i : set) {
if (!contains(i)) {
return false;
}
}
return true;
}
// --------------------------------------------------------------------------------------------
@Override
public int hashCode() {
return this.collection.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (obj instanceof FieldSet) {
return this.collection.equals(((FieldSet) obj).collection);
} else {
return false;
}
}
@Override
public String toString() {
StringBuilder bld = new StringBuilder();
bld.append(getDescriptionPrefix());
for (Integer i : this.collection) {
bld.append(i);
bld.append(',');
bld.append(' ');
}
if (this.collection.size() > 0) {
bld.setLength(bld.length() - 2);
}
bld.append(getDescriptionSuffix());
return bld.toString();
}
/**
* Since instances of FieldSet are strictly immutable, this method does not actually clone,
* but it only returns the original instance.
*
* @return This objects reference, unmodified.
*/
public FieldSet clone() {
return this;
}
// --------------------------------------------------------------------------------------------
protected String getDescriptionPrefix() {
return "(";
}
protected String getDescriptionSuffix() {
return ")";
}
}