1 /* 2 * Copyright (C) 2011 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.example.android.voicemail.common.utils; 18 19 import android.database.DatabaseUtils; 20 import android.text.TextUtils; 21 22 /** 23 * Static methods for helping us build database query selection strings. 24 */ 25 public class DbQueryUtils { 26 // Static class with helper methods, so private constructor. 27 private DbQueryUtils() { 28 } 29 30 /** Returns a WHERE clause assert equality of a field to a value for the specified table . */ 31 public static String getEqualityClause(String table, String field, String value) { 32 return getEqualityClause(table + "." + field, value); 33 } 34 35 /** Returns a WHERE clause assert equality of a field to a value. */ 36 public static String getEqualityClause(String field, String value) { 37 StringBuilder clause = new StringBuilder(); 38 clause.append(field); 39 clause.append(" = "); 40 DatabaseUtils.appendEscapedSQLString(clause, value); 41 return clause.toString(); 42 } 43 44 /** Concatenates any number of clauses using "AND". */ 45 // TODO: 0. It worries me that I can change the following "AND" to "OR" and the provider tests 46 // all pass. I can also remove the braces, and the tests all pass. 47 public static String concatenateClausesWithAnd(String... clauses) { 48 return concatenateClausesWithOperation("AND", clauses); 49 } 50 51 /** Concatenates any number of clauses using "OR". */ 52 public static String concatenateClausesWithOr(String... clauses) { 53 return concatenateClausesWithOperation("OR", clauses); 54 } 55 56 /** Concatenates any number of clauses using the specified operation. */ 57 public static String concatenateClausesWithOperation(String operation, String... clauses) { 58 // Nothing to concatenate. 59 if (clauses.length == 1) { 60 return clauses[0]; 61 } 62 63 StringBuilder builder = new StringBuilder(); 64 65 for (String clause : clauses) { 66 if (!TextUtils.isEmpty(clause)) { 67 if (builder.length() > 0) { 68 builder.append(" ").append(operation).append(" "); 69 } 70 builder.append("("); 71 builder.append(clause); 72 builder.append(")"); 73 } 74 } 75 return builder.toString(); 76 } 77 } 78
