bql.util.JsonComparator.java Source code

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Here is the source code for bql.util.JsonComparator.java

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package bql.util;

/* EXPERIMENTAL (really) */
/* Copyright (c) 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.Iterator;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * A comparator for comparing json objects. This comparator takes care of
 * reordered elements in JSONArray. {@link #STRICT} mode means the two given
 * elements must match exactly, while in {@link #SIMPLE} mode extra elements in
 * the latter is ignored.
 *
 * Check unittests {@link JsonComparatorTest} for examples on this.
 *
 * @author Sachin Shenoy
 */
public class JsonComparator {

    public static final int STRICT = 1;
    public static final int SIMPLE = 2;
    private final int policy;

    public JsonComparator(int policy) {
        this.policy = policy;
    }

    /**
     * Compares two json objects.
     *
     * @param a first element to compare
     * @param b second element to compare
     * @return true if the elements are equal as per the policy.
     */
    public boolean isEquals(Object a, Object b) {
        if (a instanceof JSONObject) {
            if (b instanceof JSONObject) {
                return isEqualsJsonObject((JSONObject) a, (JSONObject) b);
            } else {
                return false;
            }
        }

        if (a instanceof JSONArray) {
            if (b instanceof JSONArray) {
                return isEqualsJsonArray((JSONArray) a, (JSONArray) b);
            } else {
                return false;
            }
        }

        if (a instanceof Long) {
            if (b instanceof Long) {
                return isEqualsLong((Long) a, (Long) b);
            } else if (b instanceof Integer) {
                return isEqualsLong((Long) a, new Long(((Integer) b).intValue()));
            } else {
                return false;
            }
        }

        if (a instanceof Integer) {
            if (b instanceof Integer) {
                return isEqualsInteger((Integer) a, (Integer) b);
            } else if (b instanceof Long) {
                return isEqualsInteger((Integer) a, new Integer((int) ((Long) b).longValue()));
            } else {
                return false;
            }
        }

        if (a instanceof String) {
            if (b instanceof String) {
                return isEqualsString((String) a, (String) b);
            } else {
                return false;
            }
        }

        if (a instanceof Boolean) {
            if (b instanceof Boolean) {
                return isEqualsBoolean((Boolean) a, (Boolean) b);
            } else {
                return false;
            }
        }

        if (a instanceof Float || a instanceof Double) {
            double val1 = (a instanceof Float) ? ((Float) a).doubleValue() : ((Double) a).doubleValue();
            if (b instanceof Float || b instanceof Double) {
                double val2 = (b instanceof Float) ? ((Float) b).doubleValue() : ((Double) b).doubleValue();
                return (Math.abs(val1 - val2) < 0.001);
            } else {
                return false;
            }
        }

        if (a == null && b == null) {
            return true;
        }

        if (a != null && b != null) {
            return a.equals(b);
        }

        return false;
    }

    private boolean isEqualsBoolean(Boolean a, Boolean b) {
        if (a == null ^ b == null) {
            return false;
        } else if (a == null && b == null) {
            return true;
        }
        return a.equals(b);
    }

    private boolean isEqualsString(String a, String b) {
        if (a == null ^ b == null) {
            return false;
        } else if (a == null && b == null) {
            return true;
        }
        return a.equals(b);
    }

    private boolean isEqualsLong(Long a, Long b) {
        if (a == null ^ b == null) {
            return false;
        } else if (a == null && b == null) {
            return true;
        }
        return a.equals(b);
    }

    private boolean isEqualsInteger(Integer a, Integer b) {
        if (a == null ^ b == null) {
            return false;
        } else if (a == null && b == null) {
            return true;
        }
        return a.equals(b);
    }

    private boolean isEqualsJsonArray(JSONArray a, JSONArray b) {
        if (policy == STRICT) {
            if (a.length() != b.length()) {
                return false;
            }
        }

        if (policy == SIMPLE) {
            if (a.length() > b.length()) {
                return false;
            }
        }

        boolean[] am = new boolean[a.length()];
        boolean[] bm = new boolean[b.length()];

        for (int i = 0; i < a.length(); ++i)
            if (am[i] == false) {
                for (int j = 0; j < b.length(); ++j)
                    if (bm[j] == false) {
                        try {
                            if (isEquals(a.get(i), b.get(j))) {
                                am[i] = true;
                                bm[j] = true;
                                break;
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
            }

        for (int i = 0; i < am.length; ++i)
            if (!am[i]) {
                return false;
            }

        if (policy == STRICT) {
            for (int j = 0; j < bm.length; ++j)
                if (!bm[j]) {
                    return false;
                }
        }

        return true;
    }

    @SuppressWarnings("rawtypes")
    private boolean isEqualsJsonObject(JSONObject a, JSONObject b) {
        if (policy == STRICT) {
            if (a.length() != b.length()) {
                return false;
            }
        }

        if (policy == SIMPLE) {
            if (a.length() > b.length()) {
                return false;
            }
        }

        Iterator keys = a.keys();
        while (keys.hasNext()) {
            String key = (String) keys.next();
            if (!b.has(key)) {
                return false;
            }
            try {
                if (!isEquals(a.get(key), b.get(key))) {
                    return false;
                }
            } catch (JSONException e) {
                return false;
            }
        }

        return true;
    }
}