Examples with VariableContext org.apache.lucene.expressions.js.VariableContext used on opensource projects

Example 1 with VariableContext

use of org.apache.lucene.expressions.js.VariableContext in project elasticsearch by elastic.

the class ExpressionScriptEngineService method search.

@Override
public SearchScript search(CompiledScript compiledScript, SearchLookup lookup, @Nullable Map<String, Object> vars) {
    Expression expr = (Expression) compiledScript.compiled();
    MapperService mapper = lookup.doc().mapperService();
    // NOTE: if we need to do anything complicated with bindings in the future, we can just extend Bindings,
    // instead of complicating SimpleBindings (which should stay simple)
    SimpleBindings bindings = new SimpleBindings();
    ReplaceableConstDoubleValueSource specialValue = null;
    boolean needsScores = false;
    for (String variable : expr.variables) {
        try {
            if (variable.equals("_score")) {
                bindings.add(new SortField("_score", SortField.Type.SCORE));
                needsScores = true;
            } else if (variable.equals("_value")) {
                specialValue = new ReplaceableConstDoubleValueSource();
                bindings.add("_value", specialValue);
            // noop: _value is special for aggregations, and is handled in ExpressionScriptBindings
            // TODO: if some uses it in a scoring expression, they will get a nasty failure when evaluating...need a
            // way to know this is for aggregations and so _value is ok to have...
            } else if (vars != null && vars.containsKey(variable)) {
                // TODO: document and/or error if vars contains _score?
                // NOTE: by checking for the variable in vars first, it allows masking document fields with a global constant,
                // but if we were to reverse it, we could provide a way to supply dynamic defaults for documents missing the field?
                Object value = vars.get(variable);
                if (value instanceof Number) {
                    bindings.add(variable, new DoubleConstValueSource(((Number) value).doubleValue()).asDoubleValuesSource());
                } else {
                    throw new ParseException("Parameter [" + variable + "] must be a numeric type", 0);
                }
            } else {
                String fieldname = null;
                String methodname = null;
                // .value is the default for doc['field'], its optional.
                String variablename = "value";
                // true if the variable is of type doc['field'].date.xxx
                boolean dateAccessor = false;
                VariableContext[] parts = VariableContext.parse(variable);
                if (parts[0].text.equals("doc") == false) {
                    throw new ParseException("Unknown variable [" + parts[0].text + "]", 0);
                }
                if (parts.length < 2 || parts[1].type != VariableContext.Type.STR_INDEX) {
                    throw new ParseException("Variable 'doc' must be used with a specific field like: doc['myfield']", 3);
                } else {
                    fieldname = parts[1].text;
                }
                if (parts.length == 3) {
                    if (parts[2].type == VariableContext.Type.METHOD) {
                        methodname = parts[2].text;
                    } else if (parts[2].type == VariableContext.Type.MEMBER) {
                        variablename = parts[2].text;
                    } else {
                        throw new IllegalArgumentException("Only member variables or member methods may be accessed on a field when not accessing the field directly");
                    }
                }
                if (parts.length > 3) {
                    // access to the .date "object" within the field
                    if (parts.length == 4 && ("date".equals(parts[2].text) || "getDate".equals(parts[2].text))) {
                        if (parts[3].type == VariableContext.Type.METHOD) {
                            methodname = parts[3].text;
                            dateAccessor = true;
                        } else if (parts[3].type == VariableContext.Type.MEMBER) {
                            variablename = parts[3].text;
                            dateAccessor = true;
                        }
                    }
                    if (!dateAccessor) {
                        throw new IllegalArgumentException("Variable [" + variable + "] does not follow an allowed format of either doc['field'] or doc['field'].method()");
                    }
                }
                MappedFieldType fieldType = mapper.fullName(fieldname);
                if (fieldType == null) {
                    throw new ParseException("Field [" + fieldname + "] does not exist in mappings", 5);
                }
                IndexFieldData<?> fieldData = lookup.doc().fieldDataService().getForField(fieldType);
                // delegate valuesource creation based on field's type
                // there are three types of "fields" to expressions, and each one has a different "api" of variables and methods.
                final ValueSource valueSource;
                if (fieldType instanceof GeoPointFieldType) {
                    // geo
                    if (methodname == null) {
                        valueSource = GeoField.getVariable(fieldData, fieldname, variablename);
                    } else {
                        valueSource = GeoField.getMethod(fieldData, fieldname, methodname);
                    }
                } else if (fieldType instanceof DateFieldMapper.DateFieldType) {
                    if (dateAccessor) {
                        // date object
                        if (methodname == null) {
                            valueSource = DateObject.getVariable(fieldData, fieldname, variablename);
                        } else {
                            valueSource = DateObject.getMethod(fieldData, fieldname, methodname);
                        }
                    } else {
                        // date field itself
                        if (methodname == null) {
                            valueSource = DateField.getVariable(fieldData, fieldname, variablename);
                        } else {
                            valueSource = DateField.getMethod(fieldData, fieldname, methodname);
                        }
                    }
                } else if (fieldData instanceof IndexNumericFieldData) {
                    // number
                    if (methodname == null) {
                        valueSource = NumericField.getVariable(fieldData, fieldname, variablename);
                    } else {
                        valueSource = NumericField.getMethod(fieldData, fieldname, methodname);
                    }
                } else {
                    throw new ParseException("Field [" + fieldname + "] must be numeric, date, or geopoint", 5);
                }
                needsScores |= valueSource.getSortField(false).needsScores();
                bindings.add(variable, valueSource.asDoubleValuesSource());
            }
        } catch (Exception e) {
            // we defer "binding" of variables until here: give context for that variable
            throw convertToScriptException("link error", expr.sourceText, variable, e);
        }
    }
    return new ExpressionSearchScript(compiledScript, bindings, specialValue, needsScores);
}

Example 2 with VariableContext

use of org.apache.lucene.expressions.js.VariableContext in project lucene-solr by apache.

the class TestDemoExpressions method testDynamicExtendedVariableExample.

public void testDynamicExtendedVariableExample() throws Exception {
    Expression popularity = JavascriptCompiler.compile("doc['popularity'].value + magicarray[0] + fourtytwo");
    // The following is an example of how to write bindings which parse the variable name into pieces.
    // Note, however, that this requires a lot of error checking.  Each "error case" below should be
    // filled in with proper error messages for a real use case.
    Bindings bindings = new Bindings() {

        @Override
        public DoubleValuesSource getDoubleValuesSource(String name) {
            VariableContext[] var = VariableContext.parse(name);
            assert var[0].type == MEMBER;
            String base = var[0].text;
            if (base.equals("doc")) {
                if (var.length > 1 && var[1].type == STR_INDEX) {
                    String field = var[1].text;
                    if (var.length > 2 && var[2].type == MEMBER && var[2].text.equals("value")) {
                        return DoubleValuesSource.fromIntField(field);
                    } else {
                        // error case, non/missing "value" member access
                        fail("member: " + var[2].text);
                    }
                } else {
                    // error case, doc should be a str indexed array
                    fail();
                }
            } else if (base.equals("magicarray")) {
                if (var.length > 1 && var[1].type == INT_INDEX) {
                    return DoubleValuesSource.constant(2048);
                } else {
                    // error case, magic array isn't an array
                    fail();
                }
            } else if (base.equals("fourtytwo")) {
                return DoubleValuesSource.constant(42);
            } else {
                // error case (variable doesn't exist)
                fail();
            }
            throw new IllegalArgumentException("Illegal reference '" + name + "'");
        }
    };
    Sort sort = new Sort(popularity.getSortField(bindings, false));
    TopFieldDocs td = searcher.search(new MatchAllDocsQuery(), 3, sort);
    FieldDoc d = (FieldDoc) td.scoreDocs[0];
    assertEquals(2092D, (Double) d.fields[0], 1E-4);
    d = (FieldDoc) td.scoreDocs[1];
    assertEquals(2095D, (Double) d.fields[0], 1E-4);
    d = (FieldDoc) td.scoreDocs[2];
    assertEquals(2110D, (Double) d.fields[0], 1E-4);
}