--- /dev/null
+/*
+ * Copyright (C) 2008 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.
+ */
+
+package com.google.gson;
+
+import com.google.gson.internal.Streams;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * A class representing an element of Json. It could either be a {@link JsonObject}, a
+ * {@link JsonArray}, a {@link JsonPrimitive} or a {@link JsonNull}.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public abstract class JsonElement {
+ /**
+ * Returns a deep copy of this element. Immutable elements like primitives
+ * and nulls are not copied.
+ */
+ abstract JsonElement deepCopy();
+
+ /**
+ * provides check for verifying if this element is an array or not.
+ *
+ * @return true if this element is of type {@link JsonArray}, false otherwise.
+ */
+ public boolean isJsonArray() {
+ return this instanceof JsonArray;
+ }
+
+ /**
+ * provides check for verifying if this element is a Json object or not.
+ *
+ * @return true if this element is of type {@link JsonObject}, false otherwise.
+ */
+ public boolean isJsonObject() {
+ return this instanceof JsonObject;
+ }
+
+ /**
+ * provides check for verifying if this element is a primitive or not.
+ *
+ * @return true if this element is of type {@link JsonPrimitive}, false otherwise.
+ */
+ public boolean isJsonPrimitive() {
+ return this instanceof JsonPrimitive;
+ }
+
+ /**
+ * provides check for verifying if this element represents a null value or not.
+ *
+ * @return true if this element is of type {@link JsonNull}, false otherwise.
+ * @since 1.2
+ */
+ public boolean isJsonNull() {
+ return this instanceof JsonNull;
+ }
+
+ /**
+ * convenience method to get this element as a {@link JsonObject}. If the element is of some
+ * other type, a {@link ClassCastException} will result. Hence it is best to use this method
+ * after ensuring that this element is of the desired type by calling {@link #isJsonObject()}
+ * first.
+ *
+ * @return get this element as a {@link JsonObject}.
+ * @throws IllegalStateException if the element is of another type.
+ */
+ public JsonObject getAsJsonObject() {
+ if (isJsonObject()) {
+ return (JsonObject) this;
+ }
+ throw new IllegalStateException("Not a JSON Object: " + this);
+ }
+
+ /**
+ * convenience method to get this element as a {@link JsonArray}. If the element is of some
+ * other type, a {@link ClassCastException} will result. Hence it is best to use this method
+ * after ensuring that this element is of the desired type by calling {@link #isJsonArray()}
+ * first.
+ *
+ * @return get this element as a {@link JsonArray}.
+ * @throws IllegalStateException if the element is of another type.
+ */
+ public JsonArray getAsJsonArray() {
+ if (isJsonArray()) {
+ return (JsonArray) this;
+ }
+ throw new IllegalStateException("This is not a JSON Array.");
+ }
+
+ /**
+ * convenience method to get this element as a {@link JsonPrimitive}. If the element is of some
+ * other type, a {@link ClassCastException} will result. Hence it is best to use this method
+ * after ensuring that this element is of the desired type by calling {@link #isJsonPrimitive()}
+ * first.
+ *
+ * @return get this element as a {@link JsonPrimitive}.
+ * @throws IllegalStateException if the element is of another type.
+ */
+ public JsonPrimitive getAsJsonPrimitive() {
+ if (isJsonPrimitive()) {
+ return (JsonPrimitive) this;
+ }
+ throw new IllegalStateException("This is not a JSON Primitive.");
+ }
+
+ /**
+ * convenience method to get this element as a {@link JsonNull}. If the element is of some
+ * other type, a {@link ClassCastException} will result. Hence it is best to use this method
+ * after ensuring that this element is of the desired type by calling {@link #isJsonNull()}
+ * first.
+ *
+ * @return get this element as a {@link JsonNull}.
+ * @throws IllegalStateException if the element is of another type.
+ * @since 1.2
+ */
+ public JsonNull getAsJsonNull() {
+ if (isJsonNull()) {
+ return (JsonNull) this;
+ }
+ throw new IllegalStateException("This is not a JSON Null.");
+ }
+
+ /**
+ * convenience method to get this element as a boolean value.
+ *
+ * @return get this element as a primitive boolean value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * boolean value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public boolean getAsBoolean() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a {@link Boolean} value.
+ *
+ * @return get this element as a {@link Boolean} value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * boolean value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ Boolean getAsBooleanWrapper() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a {@link Number}.
+ *
+ * @return get this element as a {@link Number}.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * number.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public Number getAsNumber() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a string value.
+ *
+ * @return get this element as a string value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * string value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public String getAsString() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive double value.
+ *
+ * @return get this element as a primitive double value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * double value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public double getAsDouble() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive float value.
+ *
+ * @return get this element as a primitive float value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * float value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public float getAsFloat() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive long value.
+ *
+ * @return get this element as a primitive long value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * long value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public long getAsLong() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive integer value.
+ *
+ * @return get this element as a primitive integer value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * integer value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public int getAsInt() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive byte value.
+ *
+ * @return get this element as a primitive byte value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * byte value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ * @since 1.3
+ */
+ public byte getAsByte() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive character value.
+ *
+ * @return get this element as a primitive char value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * char value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ * @since 1.3
+ */
+ public char getAsCharacter() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a {@link BigDecimal}.
+ *
+ * @return get this element as a {@link BigDecimal}.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive}.
+ * * @throws NumberFormatException if the element is not a valid {@link BigDecimal}.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ * @since 1.2
+ */
+ public BigDecimal getAsBigDecimal() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a {@link BigInteger}.
+ *
+ * @return get this element as a {@link BigInteger}.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive}.
+ * @throws NumberFormatException if the element is not a valid {@link BigInteger}.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ * @since 1.2
+ */
+ public BigInteger getAsBigInteger() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * convenience method to get this element as a primitive short value.
+ *
+ * @return get this element as a primitive short value.
+ * @throws ClassCastException if the element is of not a {@link JsonPrimitive} and is not a valid
+ * short value.
+ * @throws IllegalStateException if the element is of the type {@link JsonArray} but contains
+ * more than a single element.
+ */
+ public short getAsShort() {
+ throw new UnsupportedOperationException(getClass().getSimpleName());
+ }
+
+ /**
+ * Returns a String representation of this element.
+ */
+ @Override
+ public String toString() {
+ try {
+ StringWriter stringWriter = new StringWriter();
+ JsonWriter jsonWriter = new JsonWriter(stringWriter);
+ jsonWriter.setLenient(true);
+ Streams.write(this, jsonWriter);
+ return stringWriter.toString();
+ } catch (IOException e) {
+ throw new AssertionError(e);
+ }
+ }
+}
projects / unical.git / blobdiff