This post explains how we can combine two or more predicates using logical operations as mentioned below 1) and 2) or 3) negate Below is an example Person package Function; public class Person { private String ssn; private String fname; private String lname; private String description; private int age; public String getSsn() { return ssn;…… Continue reading Combining Predicates
Tag: Java
Java Predicate
Java provides a new interface named Predicate which is a functional interface. A functional interface is an interface which will have exactly one abstract method in addition to one or more default methods. In the case of Predicate interface, the abstract method is test method whose signature is as shown below boolean test(T t) In…… Continue reading Java Predicate
Getting access to all printers configured in machine
This post explains how to programmatically get access to all printers configured in a machine. Java provides lookup facitlity through PrintServiceLookup class. This class has static methods through which we can get a reference to all the printers. We use the lookupPrintServices method in the PrintServiceLookup class. The api definition is as shown below public…… Continue reading Getting access to all printers configured in machine
Executing scripts written in a file using java
This post explain how to execute javascript code stored in a file. We create an instance of FileReader representing the physical file and pass it to eval method of an instance of ScriptEngine. Please refer to previous posts to know more about ScriptEngine and ScriptEngineManager The javascript code in the file that has to be…… Continue reading Executing scripts written in a file using java
Executing scripts using java
This post explain how to execute code written in scripting language like php or javascript etc in java. The scripts are executed by calling eval on an instance of ScriptEngine interface. An instance of ScriptEngine is used to represent scripting language specific engines. For example in case of JavaScript, Mozilla Rhino provided out of the…… Continue reading Executing scripts using java
Getting access to default printer
This post explains how to programmatically get access to a printer configured as default printer in a machine. Java provides PrintServiceLookup class, which provides static methods through which we can get a reference to the printer. Each printer installed in a machine is represented by an instance of PrintService interface. The PrintService interface provides methods…… Continue reading Getting access to default printer
PushBackReader Demo
This post explains PushBackReader class in java. This reader allows us to put the data read from the input stream back into the stream and reread it again. The below explains how to use it Main Class package IO; import java.io.PushbackReader; import java.io.StringReader; public class PushBackReaderDemo { public static void main(String[] args) throws Exception {…… Continue reading PushBackReader Demo
Creating dynamic proxy objects
This post explains how to create proxy objects using Java Proxy api. We need the below items to create a proxy. 1) proxy interfaces (list of interfaces the dynamic proxy class will implement). 2) dynamic proxy class is proxy class generated at runtime and implements the proxy interfaces. 3) proxy instance is an instance of…… Continue reading Creating dynamic proxy objects
Listening to unmarshalling events
By subclassing Unmarshaller.Listener abstract class, we can create listener class which will listen to unmarshling events. We can add our code if we want to perform some actions before and after unmarshalling. The Unmarshaller.Listener class has two methods which can be overridden. By default the methods doesn’t perform any actions. 1) public void beforeUnmarshal(Object target,…… Continue reading Listening to unmarshalling events
Listening to marshaling events
By subclassing Marshaller.Listener abstract class, we can create listener class which will listen to marshling events. We can add our code if we want to perform some actions before and after marshalling. The Marshaller.Listener class has two methods which can be overridden. By default the methods doesn’t perform any actions. 1) public void beforeMarshal(Object source)…… Continue reading Listening to marshaling events
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