RandomSec/main/src/com/google/refine/expr/functions/Get.java

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package com.google.refine.expr.functions;

import java.util.List;
import java.util.Properties;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.expr.HasFields;
import com.google.refine.expr.HasFieldsList;
import com.google.refine.expr.util.JsonValueConverter;
import com.google.refine.grel.Function;

public class Get implements Function {

    @Override
    public Object call(Properties bindings, Object[] args) {
        if (args.length > 1 && args.length <= 3) {
            Object v = args[0];
            Object from = args[1];
            Object to = (args.length == 3) ? args[2] : null;
            
            if (v != null && from != null) {
                if (v instanceof HasFields && from instanceof String) {
                    return ((HasFields) v).getField((String) from, bindings);
                } else if (v instanceof ObjectNode && from instanceof String) {
                    return JsonValueConverter.convert(((ObjectNode) v).get((String) from));
                } else {
                    if (from instanceof Number && (to == null || to instanceof Number)) {
                        if (v.getClass().isArray() || 
                            v instanceof List<?> || 
                            v instanceof HasFieldsList || 
                            v instanceof ArrayNode) {
                            
                            int length = 0;
                            if (v.getClass().isArray()) { 
                                length = ((Object[]) v).length;
                            } else if (v instanceof HasFieldsList) {
                                length = ((HasFieldsList) v).length();
                            } else if (v instanceof ArrayNode) {
                                length = ((ArrayNode) v).size();
                            } else {
                                length = ExpressionUtils.toObjectList(v).size();
                            }
                            
                            int start = ((Number) from).intValue();
                            if (start < 0) {
                                start = length + start;
                            }
                            start = Math.min(length, Math.max(0, start));
                            
                            if (to == null) {
                                if (v.getClass().isArray()) {
                                    return ((Object[]) v)[start];
                                } else if (v instanceof HasFieldsList) {
                                    return ((HasFieldsList) v).get(start);
                                } else if (v instanceof ArrayNode) {
                                    return JsonValueConverter.convert(((ArrayNode) v).get(start));
                                } else {
                                    return ExpressionUtils.toObjectList(v).get(start);
                                }
                            } else {
                                int end = ((Number) to).intValue();
                                            
                                if (end < 0) {
                                    end = length + end;
                                }
                                end = Math.min(length, Math.max(start, end));
                                
                                if (end > start) {
                                    if (v.getClass().isArray()) {
                                        Object[] a2 = new Object[end - start];
                                        
                                        System.arraycopy(v, start, a2, 0, end - start);
                                        
                                        return a2;
                                    } else if (v instanceof HasFieldsList) {
                                        return ((HasFieldsList) v).getSubList(start, end);
                                    } else if (v instanceof ArrayNode) {
                                        ArrayNode a = (ArrayNode) v;
                                        Object[] a2 = new Object[end - start];
                                        
                                        for (int i = 0; i < a2.length; i++) {
                                            a2[i] = JsonValueConverter.convert(a.get(start + i)); 
                                        }
                                        return a2;
                                    } else {
                                        return ExpressionUtils.toObjectList(v).subList(start, end);
                                    }
                                }
                            }
                        } else {
                            String s = (v instanceof String) ? (String) v : v.toString();
                            
                            int start = ((Number) from).intValue();
                            if (start < 0) {
                                start = s.length() + start;
                            }
                            start = Math.min(s.length(), Math.max(0, start));
                            
                            if (to != null) {
                                int end = ((Number) to).intValue();
                                if (end < 0) {
                                    end = s.length() + end;
                                }
                                end = Math.min(s.length(), Math.max(start, end));
                                
                                return s.substring(start, end);
                            } else {
                                return s.substring(start, start + 1);
                            }
                        }
                    }
                }
            }
        }
        return null;
    }

    @Override
    public String getDescription() {
        return 
            "If o has fields, returns the field named 'from' of o. " +
            "If o is an array, returns o[from, to]. " +
            "if o is a string, returns o.substring(from, to)"
        ;
    }
    
    @Override
    public String getParams() {
        return "o, number or string from, optional number to";
    }
    
    @Override
    public String getReturns() {
        return "Depends on actual arguments";
    }
}