1 /* 2 * Copyright (C) 2021 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.queryable; 18 19 import java.util.Arrays; 20 import java.util.Collection; 21 import java.util.stream.Collectors; 22 23 public interface Queryable { 24 /** 25 * Generate a string representation of the query. 26 * 27 * <p>For example, if {@code fieldName} was age, we might generate "age > 5, age < 10" 28 */ describeQuery(String fieldName)29 String describeQuery(String fieldName); 30 31 32 /** 33 * Join sub-parts of a query for use in {@link #describeQuery(String)}. 34 * 35 * <p>Queries which are not set should be null. 36 */ joinQueryStrings(String... queryStrings)37 static String joinQueryStrings(String... queryStrings) { 38 return Arrays.stream(queryStrings).filter(i -> i != null && !i.isEmpty()) 39 .collect(Collectors.joining(", ")); 40 } 41 42 /** 43 * Join sub-parts of a query for use in {@link #describeQuery(String)}. 44 * 45 * <p>Queries which are not set should be null. 46 */ joinQueryStrings(Collection<String> queryStrings)47 static String joinQueryStrings(Collection<String> queryStrings) { 48 return queryStrings.stream().filter(i -> i != null && !i.isEmpty()) 49 .collect(Collectors.joining(", ")); 50 } 51 } 52