Categories:
Audio (13)
Biotech (29)
Bytecode (36)
Database (77)
Framework (7)
Game (7)
General (507)
Graphics (53)
I/O (35)
IDE (2)
JAR Tools (101)
JavaBeans (21)
JDBC (121)
JDK (426)
JSP (20)
Logging (108)
Mail (58)
Messaging (8)
Network (84)
PDF (97)
Report (7)
Scripting (84)
Security (32)
Server (121)
Servlet (26)
SOAP (24)
Testing (54)
Web (15)
XML (309)
Collections:
Other Resources:
commons-collections4-4.4-sources.jar - Apache Commons Collections
commons-collections4-4.4-sources.jar is the source JAR file for Apache Commons Collections 4.2, which provides additional collection handling functionalities on top of JDK library.
JAR File Size and Download Location:
JAR name: commons-collections4-4.4-sources.jar Target JDK version: 8 Dependency: None File size: 715,541 bytes Release date: 05-Jul-2019 Download: Apache Commons Collections
✍: FYIcenter.com
⏎ org/apache/commons/collections4/iterators/ObjectGraphIterator.java
/* * 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.commons.collections4.iterators; import java.util.ArrayDeque; import java.util.Deque; import java.util.Iterator; import java.util.NoSuchElementException; import org.apache.commons.collections4.Transformer; /** * An Iterator that can traverse multiple iterators down an object graph. * <p> * This iterator can extract multiple objects from a complex tree-like object graph. * The iteration starts from a single root object. * It uses a <code>Transformer</code> to extract the iterators and elements. * Its main benefit is that no intermediate <code>List</code> is created. * <p> * For example, consider an object graph: * <pre> * |- Branch -- Leaf * | \- Leaf * |- Tree | /- Leaf * | |- Branch -- Leaf * Forest | \- Leaf * | |- Branch -- Leaf * | | \- Leaf * |- Tree | /- Leaf * |- Branch -- Leaf * |- Branch -- Leaf</pre> * The following <code>Transformer</code>, used in this class, will extract all * the Leaf objects without creating a combined intermediate list: * <pre> * public Object transform(Object input) { * if (input instanceof Forest) { * return ((Forest) input).treeIterator(); * } * if (input instanceof Tree) { * return ((Tree) input).branchIterator(); * } * if (input instanceof Branch) { * return ((Branch) input).leafIterator(); * } * if (input instanceof Leaf) { * return input; * } * throw new ClassCastException(); * }</pre> * <p> * Internally, iteration starts from the root object. When next is called, * the transformer is called to examine the object. The transformer will return * either an iterator or an object. If the object is an Iterator, the next element * from that iterator is obtained and the process repeats. If the element is an object * it is returned. * <p> * Under many circumstances, linking Iterators together in this manner is * more efficient (and convenient) than using nested for loops to extract a list. * * @since 3.1 */ public class ObjectGraphIterator<E> implements Iterator<E> { /** The stack of iterators */ private final Deque<Iterator<? extends E>> stack = new ArrayDeque<>(8); /** The root object in the tree */ private E root; /** The transformer to use */ private final Transformer<? super E, ? extends E> transformer; /** Whether there is another element in the iteration */ private boolean hasNext = false; /** The current iterator */ private Iterator<? extends E> currentIterator; /** The current value */ private E currentValue; /** The last used iterator, needed for remove() */ private Iterator<? extends E> lastUsedIterator; //----------------------------------------------------------------------- /** * Constructs an ObjectGraphIterator using a root object and transformer. * <p> * The root object can be an iterator, in which case it will be immediately * looped around. * * @param root the root object, null will result in an empty iterator * @param transformer the transformer to use, null will use a no effect transformer */ @SuppressWarnings("unchecked") public ObjectGraphIterator(final E root, final Transformer<? super E, ? extends E> transformer) { super(); if (root instanceof Iterator) { this.currentIterator = (Iterator<? extends E>) root; } else { this.root = root; } this.transformer = transformer; } /** * Constructs a ObjectGraphIterator that will handle an iterator of iterators. * <p> * This constructor exists for convenience to emphasise that this class can * be used to iterate over nested iterators. That is to say that the iterator * passed in here contains other iterators, which may in turn contain further * iterators. * * @param rootIterator the root iterator, null will result in an empty iterator */ public ObjectGraphIterator(final Iterator<? extends E> rootIterator) { super(); this.currentIterator = rootIterator; this.transformer = null; } //----------------------------------------------------------------------- /** * Loops around the iterators to find the next value to return. */ protected void updateCurrentIterator() { if (hasNext) { return; } if (currentIterator == null) { if (root == null) { // NOPMD // do nothing, hasNext will be false } else { if (transformer == null) { findNext(root); } else { findNext(transformer.transform(root)); } root = null; } } else { findNextByIterator(currentIterator); } } /** * Finds the next object in the iteration given any start object. * * @param value the value to start from */ @SuppressWarnings("unchecked") protected void findNext(final E value) { if (value instanceof Iterator) { // need to examine this iterator findNextByIterator((Iterator<? extends E>) value); } else { // next value found currentValue = value; hasNext = true; } } /** * Finds the next object in the iteration given an iterator. * * @param iterator the iterator to start from */ protected void findNextByIterator(final Iterator<? extends E> iterator) { if (iterator != currentIterator) { // recurse a level if (currentIterator != null) { stack.push(currentIterator); } currentIterator = iterator; } while (currentIterator.hasNext() && hasNext == false) { E next = currentIterator.next(); if (transformer != null) { next = transformer.transform(next); } findNext(next); } // if we havn't found the next value and iterators are not yet exhausted if (!hasNext && !stack.isEmpty()) { // current iterator exhausted, go up a level currentIterator = stack.pop(); findNextByIterator(currentIterator); } } //----------------------------------------------------------------------- /** * Checks whether there are any more elements in the iteration to obtain. * * @return true if elements remain in the iteration */ @Override public boolean hasNext() { updateCurrentIterator(); return hasNext; } /** * Gets the next element of the iteration. * * @return the next element from the iteration * @throws NoSuchElementException if all the Iterators are exhausted */ @Override public E next() { updateCurrentIterator(); if (hasNext == false) { throw new NoSuchElementException("No more elements in the iteration"); } lastUsedIterator = currentIterator; final E result = currentValue; currentValue = null; hasNext = false; return result; } /** * Removes from the underlying collection the last element returned. * <p> * This method calls remove() on the underlying Iterator and it may * throw an UnsupportedOperationException if the underlying Iterator * does not support this method. * * @throws UnsupportedOperationException * if the remove operator is not supported by the underlying Iterator * @throws IllegalStateException * if the next method has not yet been called, or the remove method has * already been called after the last call to the next method. */ @Override public void remove() { if (lastUsedIterator == null) { throw new IllegalStateException("Iterator remove() cannot be called at this time"); } lastUsedIterator.remove(); lastUsedIterator = null; } }
⏎ org/apache/commons/collections4/iterators/ObjectGraphIterator.java
Or download all of them as a single archive file:
File name: commons-collections4-4.4-sources.jar File size: 715541 bytes Release date: 2019-07-05 Download
⇒ Download and Install commons-collections4-4.2-bin.zip
⇐ What Is commons-collections4-4.4.jar
2020-12-15, 113782👍, 0💬
Popular Posts:
JDK 17 java.xml.jmod is the JMOD file for JDK 17 XML (eXtensible Markup Language) module. JDK 17 XML...
What Is poi-ooxml-5.2.3.jar? poi-ooxml-5.2.3.jar is one of the JAR files for Apache POI 5.2.3, which...
JDK 11 java.xml.jmod is the JMOD file for JDK 11 XML (eXtensible Markup Language) module. JDK 11 XML...
The Jakarta-ORO Java classes are a set of text-processing Java classes that provide Perl5 compatible...
Apache Ant Source Code Files are inside the Apache Ant source package file like apache-ant-1.10.10-s...