/** * Copyright 2005 The Apache Software Foundation * * Licensed 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 phases = new ArrayList();  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 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 void startNextPhase() {    currentPhase++;  }  /** Returns the current sub-node executing. */  public Progress phase() {    return (Progress)phases.get(currentPhase);  }  /** Completes this node, moving the parent node to its next child. */  public void complete() {    progress = 1.0f;    if (parent != null) {      parent.startNextPhase();    }  }  /** Called during execution on a leaf node to set its progress. */  public void set(float progress) {    this.progress = progress;  }  /** Returns the overall progress of the root. */  public float get() {    Progress node = this;    while (node.parent != null) {                 // find the root      node = parent;    }    return node.getInternal();  }  /** Computes progress in this node. */  private 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 void setStatus(String status) {    this.status = status;  }  public String toString() {    StringBuffer result = new StringBuffer();    toString(result);    return result.toString();  }  private void toString(StringBuffer buffer) {    buffer.append(status);    if (phases.size() != 0 && currentPhase < phases.size()) {      buffer.append(" > ");      phase().toString(buffer);    }  }}