src/test/java/com/fasterxml/jackson/core/json/TestJsonGenerator.java

package com.fasterxml.jackson.core.json;

import com.fasterxml.jackson.core.*;

import java.io.*;

/**
 * Set of basic unit tests for verifying that the basic generator
 * functionality works as expected.
 */
public class TestJsonGenerator
    extends com.fasterxml.jackson.core.BaseTest
{
    // // // First, tests for primitive (non-structured) values

    public void testStringWrite() throws Exception
    {
        JsonFactory jf = new JsonFactory();
        String[] inputStrings = new String[] { "", "X", "1234567890" };
        for (int useReader = 0; useReader < 2; ++useReader) {
            for (int writeString = 0; writeString < 2; ++writeString) {
                for (int strIx = 0; strIx < inputStrings.length; ++strIx) {
                    String input = inputStrings[strIx];
                    JsonGenerator gen;
                    ByteArrayOutputStream bout = new ByteArrayOutputStream();
                    if (useReader != 0) {
                        gen = jf.createGenerator(new OutputStreamWriter(bout, "UTF-8"));
                    } else {
                        gen = jf.createGenerator(bout, JsonEncoding.UTF8);
                    }
                    if (writeString > 0) {
                        gen.writeString(input);
                    } else {
                        int len = input.length();
                        char[] buffer = new char[len + 20];
                        // Let's use non-zero base offset too...
                        input.getChars(0, len, buffer, strIx);
                        gen.writeString(buffer, strIx, len);
                    }
                    gen.flush();
                    gen.close();
                    JsonParser jp = jf.createParser(new ByteArrayInputStream(bout.toByteArray()));
                
                    JsonToken t = jp.nextToken();
                    assertNotNull("Document \""+bout.toString("UTF-8")+"\" yielded no tokens", t);
                    assertEquals(JsonToken.VALUE_STRING, t);
                    assertEquals(input, jp.getText());
                    assertEquals(null, jp.nextToken());
                    jp.close();
                }
            }
        }
    }

    public void testIntWrite() throws Exception
    {
        doTestIntWrite(false);
        doTestIntWrite(true);
    }

    public void testLongWrite() throws Exception
    {
        doTestLongWrite(false);
        doTestLongWrite(true);
    }

    public void testBooleanWrite() throws Exception
    {
        for (int i = 0; i < 4; ++i) {
            boolean state = (i & 1) == 0;
            boolean pad = (i & 2) == 0;
            StringWriter sw = new StringWriter();
            JsonGenerator gen = new JsonFactory().createGenerator(sw);
            gen.writeBoolean(state);
            if (pad) {
                gen.writeRaw(" ");
            }
            gen.close();
            String docStr = sw.toString();
            JsonParser jp = createParserUsingReader(docStr);
            JsonToken t = jp.nextToken();
            String exp = Boolean.valueOf(state).toString();
            if (!exp.equals(jp.getText())) {
                fail("Expected '"+exp+"', got '"+jp.getText());
            }
            assertEquals(state ? JsonToken.VALUE_TRUE : JsonToken.VALUE_FALSE, t);
            assertEquals(null, jp.nextToken());
            jp.close();
        }
    }

    public void testNullWrite()
        throws Exception
    {
        for (int i = 0; i < 2; ++i) {
            boolean pad = (i & 1) == 0;
            StringWriter sw = new StringWriter();
            JsonGenerator gen = new JsonFactory().createGenerator(sw);
            gen.writeNull();
            if (pad) {
                gen.writeRaw(" ");
            }
            gen.close();
            String docStr = sw.toString();
            JsonParser jp = createParserUsingReader(docStr);
            JsonToken t = jp.nextToken();
            String exp = "null";
            if (!exp.equals(jp.getText())) {
                fail("Expected '"+exp+"', got '"+jp.getText());
            }
            assertEquals(JsonToken.VALUE_NULL, t);
            assertEquals(null, jp.nextToken());
            jp.close();
        }
    }
    
    // // Then root-level output testing

     public void testRootIntsWrite()
         throws Exception
     {
         StringWriter sw = new StringWriter();
         JsonGenerator gen = new JsonFactory().createGenerator(sw);
         gen.writeNumber(1);
         gen.writeNumber(2);
         gen.writeNumber(-13);
         gen.close();

         String docStr = sw.toString();

         JsonParser jp = createParserUsingReader(docStr);
         assertEquals(JsonToken.VALUE_NUMBER_INT, jp.nextToken());
         assertEquals(1, jp.getIntValue());
         assertEquals(JsonToken.VALUE_NUMBER_INT, jp.nextToken());
         assertEquals(2, jp.getIntValue());
         assertEquals(JsonToken.VALUE_NUMBER_INT, jp.nextToken());
         assertEquals(-13, jp.getIntValue());
         jp.close();
     }
    
    // Convenience methods
    
    public void testFieldValueWrites()
         throws Exception
     {
         StringWriter sw = new StringWriter();
         JsonGenerator gen = new JsonFactory().createGenerator(sw);
         gen.writeStartObject();
         gen.writeNumberField("long", 3L);
         gen.writeNumberField("double", 0.25);
         gen.writeNumberField("float", -0.25f);
         gen.writeEndObject();
         gen.close();

         assertEquals("{\"long\":3,\"double\":0.25,\"float\":-0.25}", sw.toString().trim());
     }

    /**
     * Test to verify that output context actually contains useful information
     */
    public void testOutputContext() throws Exception
    {
        StringWriter sw = new StringWriter();
        JsonGenerator gen = new JsonFactory().createGenerator(sw);
        JsonStreamContext ctxt = gen.getOutputContext();
        assertTrue(ctxt.inRoot());

        gen.writeStartObject();
        assertTrue(gen.getOutputContext().inObject());

        gen.writeFieldName("a");
        assertEquals("a", gen.getOutputContext().getCurrentName());

        gen.writeStartArray();
        assertTrue(gen.getOutputContext().inArray());

        gen.writeStartObject();
        assertTrue(gen.getOutputContext().inObject());

        gen.writeFieldName("b");
        ctxt = gen.getOutputContext();
        assertEquals("b", ctxt.getCurrentName());
        gen.writeNumber(123);
        assertEquals("b", ctxt.getCurrentName());

        gen.writeFieldName("c");
        assertEquals("c", gen.getOutputContext().getCurrentName());
        gen.writeNumber(5);
//        assertEquals("c", gen.getOutputContext().getCurrentName());

        gen.writeFieldName("d");
        assertEquals("d", gen.getOutputContext().getCurrentName());

        gen.writeStartArray();
        ctxt = gen.getOutputContext();
        assertTrue(ctxt.inArray());
        assertEquals(0, ctxt.getCurrentIndex());
        assertEquals(0, ctxt.getEntryCount());

        gen.writeBoolean(true);
        ctxt = gen.getOutputContext();
        assertTrue(ctxt.inArray());
        // NOTE: index still refers to currently output entry
        assertEquals(0, ctxt.getCurrentIndex());
        assertEquals(1, ctxt.getEntryCount());

        gen.writeNumber(3);
        ctxt = gen.getOutputContext();
        assertTrue(ctxt.inArray());
        assertEquals(1, ctxt.getCurrentIndex());
        assertEquals(2, ctxt.getEntryCount());
        
        gen.writeEndArray();
        assertTrue(gen.getOutputContext().inObject());
        
        gen.writeEndObject();
        assertTrue(gen.getOutputContext().inArray());

        gen.writeEndArray();
        assertTrue(gen.getOutputContext().inObject());

        gen.writeEndObject();

        assertTrue(gen.getOutputContext().inRoot());
        
        gen.close();
    }

    // [core#167]: no error for writing field name twice
    public void testDupFieldNameWrites() throws Exception
    {
        JsonFactory f = new JsonFactory();
        _testDupFieldNameWrites(f, false);
        _testDupFieldNameWrites(f, true);        
    }

    private void _testDupFieldNameWrites(JsonFactory f, boolean useReader) throws Exception
    {
        JsonGenerator gen;
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        if (useReader) {
            gen = f.createGenerator(new OutputStreamWriter(bout, "UTF-8"));
        } else {
            gen = f.createGenerator(bout, JsonEncoding.UTF8);
        }
        gen.writeStartObject();
        gen.writeFieldName("a");
        
        try {
            gen.writeFieldName("b");
            gen.flush();
            String json = bout.toString("UTF-8");
            fail("Should not have let two consequtive field name writes succeed: output = "+json);
        } catch (JsonProcessingException e) {
            verifyException(e, "can not write a field name, expecting a value");
        }
        gen.close();
    }
            
    /*
    /**********************************************************
    /* Internal methods
    /**********************************************************
     */
    
    private void doTestIntWrite(boolean pad)
        throws Exception
    {
        int[] VALUES = new int[] {
            0, 1, -9, 32, -32, 57, 189, 2017, -9999, 13240, 123456,
            1111111, 22222222, 123456789, Integer.MAX_VALUE, Integer.MAX_VALUE
        };
        for (int i = 0; i < VALUES.length; ++i) {
            int VALUE = VALUES[i];
            StringWriter sw = new StringWriter();
            JsonGenerator gen = new JsonFactory().createGenerator(sw);
            gen.writeNumber(VALUE);
            if (pad) {
                gen.writeRaw(" ");
            }
            gen.close();
            String docStr = sw.toString();
            JsonParser jp = createParserUsingReader(docStr);
            JsonToken t = jp.nextToken();
            assertNotNull("Document \""+docStr+"\" yielded no tokens", t);
            // Number are always available as lexical representation too
            String exp = ""+VALUE;
            if (!exp.equals(jp.getText())) {
                fail("Expected '"+exp+"', got '"+jp.getText());
            }
            assertEquals(JsonToken.VALUE_NUMBER_INT, t);
            assertEquals(VALUE, jp.getIntValue());
            assertEquals(null, jp.nextToken());
            jp.close();
        }
    }

    private void doTestLongWrite(boolean pad)
        throws Exception
    {
        long[] VALUES = new long[] {
            0L, 1L, -1L, -12005002294L, Long.MIN_VALUE, Long.MAX_VALUE
        };
        for (int i = 0; i < VALUES.length; ++i) {
            long VALUE = VALUES[i];
            StringWriter sw = new StringWriter();
            JsonGenerator gen = new JsonFactory().createGenerator(sw);
            gen.writeNumber(VALUE);
            if (pad) {
                gen.writeRaw(" ");
            }
            gen.close();
            String docStr = sw.toString();
            JsonParser jp = createParserUsingReader(docStr);
            JsonToken t = jp.nextToken();
            assertNotNull("Document \""+docStr+"\" yielded no tokens", t);
            String exp = ""+VALUE;
            if (!exp.equals(jp.getText())) {
                fail("Expected '"+exp+"', got '"+jp.getText());
            }
            assertEquals(JsonToken.VALUE_NUMBER_INT, t);
            assertEquals(VALUE, jp.getLongValue());
            assertEquals(null, jp.nextToken());
            jp.close();
        }
    }
}