Java Factory Pattern Example

BuilderFactoryExample.java

public final class Main {

    public static void main(String[...] args) {
        Bar s = new Bar.Builder(new Object())
                .withObject1(new Object())
                .withObject2(new Object())
                .withString("s").build();
        Bar build = Bar.builder(new Object()).build();
    }

    private static class Bar {

        private final String string;
        private final Object object1;
        private final Object object2;
        private final Object object3;

        private Bar(String string, Object object1, Object object2, Object object3) {
            this.string = string;
            this.object1 = object1;
            this.object2 = object2;
            this.object3 = object3;
        }

        public static Builder builder(Object o) {
            return new Builder(o);
        }

        private static class Builder {
            private Object object1 = new Double(1);
            private Object object2;
            private final Object object3;
            private String string;

            private Builder(Object object3) {
                this.object3 = object3;
            }

            public Builder withString(String s) {
                this.string = s;
                return this;
            }

            public Builder withObject1(Object o) {
                this.object1 = o;
                return this;
            }

            public Builder withObject2(Object o) {
                this.object2 = o;
                return this;
            }

            public Bar build() {
                return new Bar(string, object1, object2, object3);
            }
        }
    }
}