5a17acfd70
git-svn-id: http://google-refine.googlecode.com/svn/trunk@1613 7d457c2a-affb-35e4-300a-418c747d4874
84 lines
3.1 KiB
Java
84 lines
3.1 KiB
Java
/*
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Copyright 2010, Google Inc.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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* Neither the name of Google Inc. nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package com.google.refine.grel.ast;
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import java.util.Properties;
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import org.json.JSONException;
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import org.json.JSONObject;
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import com.google.refine.expr.EvalError;
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import com.google.refine.expr.Evaluable;
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import com.google.refine.expr.ExpressionUtils;
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import com.google.refine.expr.HasFields;
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/**
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* An abstract syntax tree node encapsulating a field accessor,
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* e.g., "cell.value" is accessing the field named "value" on the
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* variable called "cell".
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*/
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public class FieldAccessorExpr implements Evaluable {
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final protected Evaluable _inner;
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final protected String _fieldName;
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public FieldAccessorExpr(Evaluable inner, String fieldName) {
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_inner = inner;
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_fieldName = fieldName;
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}
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public Object evaluate(Properties bindings) {
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Object o = _inner.evaluate(bindings);
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if (ExpressionUtils.isError(o)) {
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return o; // bubble the error up
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} else if (o == null) {
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return new EvalError("Cannot retrieve field from null");
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} else if (o instanceof HasFields) {
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return ((HasFields) o).getField(_fieldName, bindings);
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} else if (o instanceof JSONObject) {
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try {
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return ((JSONObject) o).get(_fieldName);
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} catch (JSONException e) {
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return new EvalError("Object does not have any field, including " + _fieldName);
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}
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} else {
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return new EvalError("Object does not have any field, including " + _fieldName);
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}
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}
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@Override
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public String toString() {
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return _inner.toString() + "." + _fieldName;
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}
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}
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