A Boolean Expression Parser
The library can help parse complex and nested boolean expressions. The filter expression is SQL-like syntax, where you can use boolean operators and parentheses to combine individual filters.
Format: ${attributeName}:${value}
Example: name:john
Format: ${attributeName} ${operator} ${value}
Example: price > 12.99
The ${value} must be numeric. Supported operators are <, <=, =, !=, >= and >, with the same semantics as in virtually all programming languages.
Format: ${attributeName}:${lowerBound} TO ${upperBound}
Example: price:5.99 TO 100
${lowerBound} and ${upperBound} must be numeric. Both are inclusive.
Example:
price < 10 AND (category:Book OR NOT category:Ebook)
Individual filters can be combined via boolean operators. The following operators are supported:
OR: must match any of the combined conditions (disjunction)AND: must match all of the combined conditions (conjunction)NOT: negate a filter
Parentheses, ( and ), can be used for grouping.
You cannot negate a group of filters, only an individual filter. For example, NOT(filter1 OR filter2) is not allowed.
- Phrases that includes quotes, like
content:"It's a wonderful day" - Phrases that includes quotes, like
attribute:'She said "Hello World"'
POM
<dependencies>
<dependency>
<groupId>com.github.sidhant92</groupId>
<artifactId>boolparser</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>Gradle
dependencies {
implementation "com.github.sidhant92:boolparser:1.0.3"
}
final PEGBoolExpressionParser boolExpressionParser = new PEGBoolExpressionParser();
final Optional<Node> nodeOptional = boolExpressionParser.parseExpression("name:test");
StringToken
private final String field;
private final String value;
NumericToken
private final String field;
private final Object value;
private final Operator operator;
private final DataType dataType;
NumericRangeToken
private final String field;
private final Object fromValue;
private final Object toValue;
private final DataType fromDataType;
private final DataType toDataType;
BoolExpression
private final List<Node> orOperations = new ArrayList<>();
private final List<Node> andOperations = new ArrayList<>();
private final List<Node> notOperations = new ArrayList<>();
The library can be used to evaluate a boolean expression.
The following Data Types are supported:
- String
- Integers
- Decimals
- Boolean
- App Version
Usage examples:
Simple Numerical Comparison
final BooleanExpressionEvaluator booleanExpressionEvaluator = new BooleanExpressionEvaluator();
final Map<String, Object> data = new HashMap<>();
data.put("age", 26);
final Optional<Boolean> booleanOptional = booleanExpressionEvaluator.evaluate("age >= 27", data);
assertTrue(booleanOptional.isPresent());
assertFalse(booleanOptional.get());
Boolean Comparison
final BooleanExpressionEvaluator booleanExpressionEvaluator = new BooleanExpressionEvaluator();
final Map<String, Object> data = new HashMap<>();
data.put("age", 25);
data.put("name", "sid");
final Optional<Boolean> booleanOptional = booleanExpressionEvaluator.evaluate("name:sid AND age = 25", data);
assertTrue(booleanOptional.isPresent());
assertTrue(booleanOptional.get());
Nested Boolean Comparison
final BooleanExpressionEvaluator booleanExpressionEvaluator = new BooleanExpressionEvaluator();
final Map<String, Object> data = new HashMap<>();
data.put("age", 25);
data.put("name", "sid");
data.put("num", 45);
final Optional<Boolean> booleanOptional = booleanExpressionEvaluator.evaluate("name:sid AND (age = 25 OR num = 44)", data);
assertTrue(booleanOptional.isPresent());
assertTrue(booleanOptional.get());
App Version Comparison
final BooleanExpressionEvaluator booleanExpressionEvaluator = new BooleanExpressionEvaluator();
final Map<String, Object> data = new HashMap<>();
data.put("app_version", "1.5.9");
final Optional<Boolean> booleanOptional = booleanExpressionEvaluator.evaluate("app_version < 1.5.10", data);
assertTrue(booleanOptional.isPresent());
assertTrue(booleanOptional.get());
The return type is Optional<Boolean>. If its absent which means parsing has failed and any fallback can be used.
For a complete list of examples please check out the test file