StringJoiner merge with different delimiters

stringjoiner-merge-multiple-delimiters.md

StringJoiner class merge operation exampe

Merge 2 instance of StringJoiner will use the delimiters of both the instances.

    /**
     * Test of main method, of class StringJoinerSample.
     */
    @org.junit.Test
    public void mergingWithDifferentDelimiters() {
        System.out.println("main");
        final String[] pstStates = {"CA", "NV", "NB"};
        final String[] estStates = {"NY", "NJ", "FL"};

        StringJoiner instance1 = new StringJoiner(" AND ", "[", "]");
        StringJoiner instance2 = new StringJoiner(" OR ", "{", "}");
        Arrays.asList(pstStates).forEach(state -> instance1.add(state));
        Arrays.asList(estStates).forEach(state -> instance2.add(state));
      
        instance1.merge(instance2);

        final String expected = "[CA AND NV AND NB AND NY OR NJ OR FL]";
        final String actual = instance1.toString();
        System.out.println("Actual Output : " + actual);
        assertThat(actual, CoreMatchers.startsWith("["));
        assertThat(actual, CoreMatchers.endsWith("]"));
        assertEquals("Same delimiter should be used when merging.", expected, actual);
    }

Using StringJoiner#add method

     @org.junit.Test
    public void additionInsteadOfMerge() {
        System.out.println("main");
        final String[] pstStates = {"CA", "NV", "NB"};
        final String[] estStates = {"NY", "NJ", "FL"};

        StringJoiner instance1 = new StringJoiner(" AND ", "[", "]");
        StringJoiner instance2 = new StringJoiner(" OR ", "{", "}");
        Arrays.asList(pstStates).forEach(state -> instance1.add(state));
        Arrays.asList(estStates).forEach(state -> instance2.add(state));
      
        instance1.add(instance2.toString());

        final String expected = "[CA AND NV AND NB AND {NY OR NJ OR FL}]";
        final String actual = instance1.toString();
        System.out.println("Actual Output : " + actual);
        assertThat(actual, CoreMatchers.startsWith("["));
        assertThat(actual, CoreMatchers.endsWith("]"));
        assertEquals("Same delimiter should be used when merging.", expected, actual);
    }

Note : When using add instead of merge the prefix and suffix of the merged instance will be appended.

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