Progress.java
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上传日期:2018-01-08
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文件大小:4k
- /**
- * 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.hadoop.util;
- import java.util.ArrayList;
- /** Utility to assist with generation of progress reports. Applications build
- * a hierarchy of {@link Progress} instances, each modelling a phase of
- * execution. The root is constructed with {@link #Progress()}. Nodes for
- * sub-phases are created by calling {@link #addPhase()}.
- */
- public class Progress {
- private String status = "";
- private float progress;
- private int currentPhase;
- private ArrayList<Progress> phases = new ArrayList<Progress>();
- private Progress parent;
- private float progressPerPhase;
- /** Creates a new root node. */
- public Progress() {}
- /** Adds a named node to the tree. */
- public Progress addPhase(String status) {
- Progress phase = addPhase();
- phase.setStatus(status);
- return phase;
- }
- /** Adds a node to the tree. */
- public synchronized Progress addPhase() {
- Progress phase = new Progress();
- phases.add(phase);
- phase.parent = this;
- progressPerPhase = 1.0f / (float)phases.size();
- return phase;
- }
- /** Called during execution to move to the next phase at this level in the
- * tree. */
- public synchronized void startNextPhase() {
- currentPhase++;
- }
- /** Returns the current sub-node executing. */
- public synchronized Progress phase() {
- return phases.get(currentPhase);
- }
- /** Completes this node, moving the parent node to its next child. */
- public void complete() {
- // we have to traverse up to our parent, so be careful about locking.
- Progress myParent;
- synchronized(this) {
- progress = 1.0f;
- myParent = parent;
- }
- if (myParent != null) {
- // this will synchronize on the parent, so we make sure we release
- // our lock before getting the parent's, since we're traversing
- // against the normal traversal direction used by get() or toString().
- // We don't need transactional semantics, so we're OK doing this.
- myParent.startNextPhase();
- }
- }
- /** Called during execution on a leaf node to set its progress. */
- public synchronized void set(float progress) {
- this.progress = progress;
- }
- /** Returns the overall progress of the root. */
- // this method probably does not need to be synchronized as getINternal() is synchronized
- // and the node's parent never changes. Still, it doesn't hurt.
- public synchronized float get() {
- Progress node = this;
- while (node.parent != null) { // find the root
- node = parent;
- }
- return node.getInternal();
- }
- /** Computes progress in this node. */
- private synchronized float getInternal() {
- int phaseCount = phases.size();
- if (phaseCount != 0) {
- float subProgress =
- currentPhase < phaseCount ? phase().getInternal() : 0.0f;
- return progressPerPhase*(currentPhase + subProgress);
- } else {
- return progress;
- }
- }
- public synchronized void setStatus(String status) {
- this.status = status;
- }
- public String toString() {
- StringBuffer result = new StringBuffer();
- toString(result);
- return result.toString();
- }
- private synchronized void toString(StringBuffer buffer) {
- buffer.append(status);
- if (phases.size() != 0 && currentPhase < phases.size()) {
- buffer.append(" > ");
- phase().toString(buffer);
- }
- }
- }