1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.voicemail.impl.mail.store.imap; 18 19 /** 20 * Class representing "element"s in IMAP responses. 21 * 22 * <p>Class hierarchy: 23 * 24 * <pre> 25 * ImapElement 26 * | 27 * |-- ImapElement.NONE (for 'index out of range') 28 * | 29 * |-- ImapList (isList() == true) 30 * | | 31 * | |-- ImapList.EMPTY 32 * | | 33 * | --- ImapResponse 34 * | 35 * --- ImapString (isString() == true) 36 * | 37 * |-- ImapString.EMPTY 38 * | 39 * |-- ImapSimpleString 40 * | 41 * |-- ImapMemoryLiteral 42 * | 43 * --- ImapTempFileLiteral 44 * </pre> 45 */ 46 public abstract class ImapElement { 47 /** 48 * An element that is returned by {@link ImapList#getElementOrNone} to indicate an index is out of 49 * range. 50 */ 51 public static final ImapElement NONE = 52 new ImapElement() { 53 @Override 54 public void destroy() { 55 // Don't call super.destroy(). 56 // It's a shared object. We don't want the mDestroyed to be set on this. 57 } 58 59 @Override 60 public boolean isList() { 61 return false; 62 } 63 64 @Override 65 public boolean isString() { 66 return false; 67 } 68 69 @Override 70 public String toString() { 71 return "[NO ELEMENT]"; 72 } 73 74 @Override 75 public boolean equalsForTest(ImapElement that) { 76 return super.equalsForTest(that); 77 } 78 }; 79 80 private boolean mDestroyed = false; 81 82 public abstract boolean isList(); 83 84 public abstract boolean isString(); 85 86 protected boolean isDestroyed() { 87 return mDestroyed; 88 } 89 90 /** 91 * Clean up the resources used by the instance. It's for removing a temp file used by {@link 92 * ImapTempFileLiteral}. 93 */ 94 public void destroy() { 95 mDestroyed = true; 96 } 97 98 /** Throws {@link RuntimeException} if it's already destroyed. */ 99 protected final void checkNotDestroyed() { 100 if (mDestroyed) { 101 throw new RuntimeException("Already destroyed"); 102 } 103 } 104 105 /** 106 * Return a string that represents this object; it's purely for the debug purpose. Don't mistake 107 * it for {@link ImapString#getString}. 108 * 109 * <p>Abstract to force subclasses to implement it. 110 */ 111 @Override 112 public abstract String toString(); 113 114 /** 115 * The equals implementation that is intended to be used only for unit testing. (Because it may be 116 * heavy and has a special sense of "equal" for testing.) 117 */ 118 public boolean equalsForTest(ImapElement that) { 119 if (that == null) { 120 return false; 121 } 122 return this.getClass() == that.getClass(); // Has to be the same class. 123 } 124 } 125