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 package com.android.providers.contacts.util;
17 
18 import android.content.ContentValues;
19 import android.database.DatabaseUtils;
20 import android.text.TextUtils;
21 
22 import java.util.HashMap;
23 import java.util.Set;
24 
25 /**
26  * Static methods for helping us build database query selection strings.
27  */
28 public class DbQueryUtils {
29     // Static class with helper methods, so private constructor.
DbQueryUtils()30     private DbQueryUtils() {
31     }
32 
33     /** Returns a WHERE clause asserting equality of a field to a value. */
getEqualityClause(String field, String value)34     public static String getEqualityClause(String field, String value) {
35         return getClauseWithOperator(field, "=", value);
36     }
37 
38     /** Returns a WHERE clause asserting equality of a field to a value. */
getEqualityClause(String field, long value)39     public static String getEqualityClause(String field, long value) {
40         return getClauseWithOperator(field, "=", value);
41     }
42 
43     /** Returns a WHERE clause asserting in-equality of a field to a value. */
getInequalityClause(String field, long value)44     public static String getInequalityClause(String field, long value) {
45         return getClauseWithOperator(field, "!=", value);
46     }
47 
getClauseWithOperator(String field, String operator, String value)48     private static String getClauseWithOperator(String field, String operator, String value) {
49         StringBuilder clause = new StringBuilder();
50         clause.append("(");
51         clause.append(field);
52         clause.append(" ").append(operator).append(" ");
53         DatabaseUtils.appendEscapedSQLString(clause, value);
54         clause.append(")");
55         return clause.toString();
56     }
57 
getClauseWithOperator(String field, String operator, long value)58     private static String getClauseWithOperator(String field, String operator, long value) {
59         StringBuilder clause = new StringBuilder();
60         clause.append("(");
61         clause.append(field);
62         clause.append(" ").append(operator).append(" ");
63         clause.append(value);
64         clause.append(")");
65         return clause.toString();
66     }
67 
68     /** Concatenates any number of clauses using "AND". */
concatenateClauses(String... clauses)69     public static String concatenateClauses(String... clauses) {
70         StringBuilder builder = new StringBuilder();
71         for (String clause : clauses) {
72             if (!TextUtils.isEmpty(clause)) {
73                 if (builder.length() > 0) {
74                     builder.append(" AND ");
75                 }
76                 builder.append("(");
77                 builder.append(clause);
78                 builder.append(")");
79             }
80         }
81         return builder.toString();
82     }
83 
84     /**
85      * Checks if the given ContentValues contains values within the projection
86      * map.
87      *
88      * @throws IllegalArgumentException if any value in values is not found in
89      * the projection map.
90      */
checkForSupportedColumns(HashMap<String, String> projectionMap, ContentValues values)91     public static void checkForSupportedColumns(HashMap<String, String> projectionMap,
92             ContentValues values) {
93         checkForSupportedColumns(projectionMap.keySet(), values, "Is invalid.");
94     }
95 
96     /**
97      * @see #checkForSupportedColumns(HashMap, ContentValues)
98      */
checkForSupportedColumns(Set<String> allowedColumns, ContentValues values, String msgSuffix)99     public static void checkForSupportedColumns(Set<String> allowedColumns, ContentValues values,
100             String msgSuffix) {
101         for (String requestedColumn : values.keySet()) {
102             if (!allowedColumns.contains(requestedColumn)) {
103                 throw new IllegalArgumentException("Column '" + requestedColumn + "'. " +
104                         msgSuffix);
105             }
106         }
107     }
108 
109     /**
110      * Escape values to be used in LIKE sqlite clause.
111      *
112      * The LIKE clause has two special characters: '%' and '_'.  If either of these
113      * characters need to be matched literally, then they must be escaped like so:
114      *
115      * WHERE value LIKE 'android\_%' ESCAPE '\'
116      *
117      * The ESCAPE clause is required and no default exists as the escape character in this context.
118      * Since the escape character needs to be defined as part of the sql string, it must be
119      * provided to this method so the escape characters match.
120      *
121      * @param sb The StringBuilder to append the escaped value to.
122      * @param value The value to be escaped.
123      * @param escapeChar The escape character to be defined in the sql ESCAPE clause.
124      */
escapeLikeValue(StringBuilder sb, String value, char escapeChar)125     public static void escapeLikeValue(StringBuilder sb, String value, char escapeChar) {
126         for (int i = 0; i < value.length(); i++) {
127             char ch = value.charAt(i);
128             if (ch == '%' || ch == '_' || ch == escapeChar) {
129                 sb.append(escapeChar);
130             }
131             sb.append(ch);
132         }
133     }
134 
135 }
136