/*
* Copyright (C) 2011 The Android Open Source Project
*
* 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 com.example.android.voicemail.common.utils;
import android.database.DatabaseUtils;
import android.text.TextUtils;
/**
* Static methods for helping us build database query selection strings.
*/
public class DbQueryUtils {
// Static class with helper methods, so private constructor.
private DbQueryUtils() {
}
/** Returns a WHERE clause assert equality of a field to a value for the specified table . */
public static String getEqualityClause(String table, String field, String value) {
return getEqualityClause(table + "." + field, value);
}
/** Returns a WHERE clause assert equality of a field to a value. */
public static String getEqualityClause(String field, String value) {
StringBuilder clause = new StringBuilder();
clause.append(field);
clause.append(" = ");
DatabaseUtils.appendEscapedSQLString(clause, value);
return clause.toString();
}
/** Concatenates any number of clauses using "AND". */
// TODO: 0. It worries me that I can change the following "AND" to "OR" and the provider tests
// all pass. I can also remove the braces, and the tests all pass.
public static String concatenateClausesWithAnd(String... clauses) {
return concatenateClausesWithOperation("AND", clauses);
}
/** Concatenates any number of clauses using "OR". */
public static String concatenateClausesWithOr(String... clauses) {
return concatenateClausesWithOperation("OR", clauses);
}
/** Concatenates any number of clauses using the specified operation. */
public static String concatenateClausesWithOperation(String operation, String... clauses) {
// Nothing to concatenate.
if (clauses.length == 1) {
return clauses[0];
}
StringBuilder builder = new StringBuilder();
for (String clause : clauses) {
if (!TextUtils.isEmpty(clause)) {
if (builder.length() > 0) {
builder.append(" ").append(operation).append(" ");
}
builder.append("(");
builder.append(clause);
builder.append(")");
}
}
return builder.toString();
}
}