jinterface: implement support for maps

The API and implementation are simplistic, like for lists and tuples,
using arrays and without any connection to java.util.Map.

5 files changed, 322 insertions, 0 deletions

diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangMap.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangMap.java
new file mode 100644
index 0000000000..7c1cf84e98
--- /dev/null
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangMap.java
@@ -0,0 +1,293 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2000-2013. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+package com.ericsson.otp.erlang;
+
+import java.io.Serializable;
+
+/**
+ * Provides a Java representation of Erlang maps. Maps are created from one or
+ * more arbitrary Erlang terms.
+ * 
+ * <p>
+ * The arity of the map is the number of elements it contains. The keys and
+ * values can be retrieved as arrays and the value for a key can be queried.
+ * 
+ */
+public class OtpErlangMap extends OtpErlangObject implements Serializable,
+	Cloneable {
+    // don't change this!
+    private static final long serialVersionUID = -6410770117696198497L;
+
+    private static final OtpErlangObject[] NO_ELEMENTS = new OtpErlangObject[0];
+
+    private OtpErlangObject[] keys = NO_ELEMENTS;
+    private OtpErlangObject[] values = NO_ELEMENTS;
+
+    /**
+     * Create a map from an array of keys and an array of values.
+     * 
+     * @param keys
+     *            the array of terms to create the map keys from.
+     * @param values
+     *            the array of terms to create the map values from.
+     * 
+     * @exception java.lang.IllegalArgumentException
+     *                if any array is empty (null) or contains null elements.
+     */
+    public OtpErlangMap(final OtpErlangObject[] keys,
+	    final OtpErlangObject[] values) {
+	this(keys, 0, keys.length, values, 0, values.length);
+    }
+
+    /**
+     * Create a map from an array of terms.
+     * 
+     * @param elems
+     *            the array of terms to create the map from.
+     * @param start
+     *            the offset of the first term to insert.
+     * @param vcount
+     *            the number of terms to insert.
+     * 
+     * @exception java.lang.IllegalArgumentException
+     *                if any array is empty (null) or contains null elements.
+     */
+    public OtpErlangMap(final OtpErlangObject[] keys, final int kstart,
+	    final int kcount, final OtpErlangObject[] values, final int vstart,
+	    final int vcount) {
+	if (keys == null || values == null) {
+	    throw new java.lang.IllegalArgumentException(
+		    "Map content can't be null");
+	} else if (kcount != vcount) {
+	    throw new java.lang.IllegalArgumentException(
+		    "Map keys and values must have same arity");
+	} else if (vcount < 1) {
+	    this.keys = NO_ELEMENTS;
+	    this.values = NO_ELEMENTS;
+	} else {
+	    this.keys = new OtpErlangObject[vcount];
+	    for (int i = 0; i < vcount; i++) {
+		if (keys[kstart + i] != null) {
+		    this.keys[i] = keys[kstart + i];
+		} else {
+		    throw new java.lang.IllegalArgumentException(
+			    "Map key cannot be null (element" + (kstart + i)
+				    + ")");
+		}
+	    }
+	    this.values = new OtpErlangObject[vcount];
+	    for (int i = 0; i < vcount; i++) {
+		if (values[vstart + i] != null) {
+		    this.values[i] = values[vstart + i];
+		} else {
+		    throw new java.lang.IllegalArgumentException(
+			    "Map value cannot be null (element" + (vstart + i)
+				    + ")");
+		}
+	    }
+	}
+    }
+
+    /**
+     * Create a map from a stream containing a map encoded in Erlang external
+     * format.
+     * 
+     * @param buf
+     *            the stream containing the encoded map.
+     * 
+     * @exception OtpErlangDecodeException
+     *                if the buffer does not contain a valid external
+     *                representation of an Erlang map.
+     */
+    public OtpErlangMap(final OtpInputStream buf)
+	    throws OtpErlangDecodeException {
+	final int arity = buf.read_map_head();
+
+	if (arity > 0) {
+	    keys = new OtpErlangObject[arity];
+	    values = new OtpErlangObject[arity];
+
+	    for (int i = 0; i < arity; i++) {
+		keys[i] = buf.read_any();
+	    }
+	    for (int i = 0; i < arity; i++) {
+		values[i] = buf.read_any();
+	    }
+	} else {
+	    keys = NO_ELEMENTS;
+	    values = NO_ELEMENTS;
+	}
+    }
+
+    /**
+     * Get the arity of the map.
+     * 
+     * @return the number of elements contained in the map.
+     */
+    public int arity() {
+	return keys.length;
+    }
+
+    /**
+     * Get the specified value from the map.
+     * 
+     * @param key
+     *            the key of the requested value.
+     * 
+     * @return the requested value, of null if key is not a valid key.
+     */
+    public OtpErlangObject get(final OtpErlangObject key) {
+	if (key == null) {
+	    return null;
+	}
+	for (int i = 0; i < keys.length; i++) {
+	    if (key.equals(keys[i])) {
+		return values[i];
+	    }
+	}
+	return null;
+    }
+
+    /**
+     * Get all the keys from the map as an array.
+     * 
+     * @return an array containing all of the map's keys.
+     */
+    public OtpErlangObject[] keys() {
+	final OtpErlangObject[] res = new OtpErlangObject[arity()];
+	System.arraycopy(keys, 0, res, 0, res.length);
+	return res;
+    }
+
+    /**
+     * Get all the values from the map as an array.
+     * 
+     * @return an array containing all of the map's values.
+     */
+    public OtpErlangObject[] values() {
+	final OtpErlangObject[] res = new OtpErlangObject[arity()];
+	System.arraycopy(values, 0, res, 0, res.length);
+	return res;
+    }
+
+    /**
+     * Get the string representation of the map.
+     * 
+     * @return the string representation of the map.
+     */
+    @Override
+    public String toString() {
+	int i;
+	final StringBuffer s = new StringBuffer();
+	final int arity = values.length;
+
+	s.append("#{");
+
+	for (i = 0; i < arity; i++) {
+	    if (i > 0) {
+		s.append(",");
+	    }
+	    s.append(keys[i].toString());
+	    s.append(" => ");
+	    s.append(values[i].toString());
+	}
+
+	s.append("}");
+
+	return s.toString();
+    }
+
+    /**
+     * Convert this map to the equivalent Erlang external representation.
+     * 
+     * @param buf
+     *            an output stream to which the encoded map should be written.
+     */
+    @Override
+    public void encode(final OtpOutputStream buf) {
+	final int arity = values.length;
+
+	buf.write_map_head(arity);
+
+	for (int i = 0; i < arity; i++) {
+	    buf.write_any(keys[i]);
+	}
+	for (int i = 0; i < arity; i++) {
+	    buf.write_any(values[i]);
+	}
+    }
+
+    /**
+     * Determine if two maps are equal. Maps are equal if they have the same
+     * arity and all of the elements are equal.
+     * 
+     * @param o
+     *            the map to compare to.
+     * 
+     * @return true if the maps have the same arity and all the elements are
+     *         equal.
+     */
+    @Override
+    public boolean equals(final Object o) {
+	if (!(o instanceof OtpErlangMap)) {
+	    return false;
+	}
+
+	final OtpErlangMap t = (OtpErlangMap) o;
+	final int a = arity();
+
+	if (a != t.arity()) {
+	    return false;
+	}
+
+	for (int i = 0; i < a; i++) {
+	    if (!keys[i].equals(t.keys[i])) {
+		return false; // early exit
+	    }
+	}
+	for (int i = 0; i < a; i++) {
+	    if (!values[i].equals(t.values[i])) {
+		return false; // early exit
+	    }
+	}
+
+	return true;
+    }
+
+    @Override
+    protected int doHashCode() {
+	final OtpErlangObject.Hash hash = new OtpErlangObject.Hash(9);
+	final int a = arity();
+	hash.combine(a);
+	for (int i = 0; i < a; i++) {
+	    hash.combine(keys[i].hashCode());
+	}
+	for (int i = 0; i < a; i++) {
+	    hash.combine(values[i].hashCode());
+	}
+	return hash.valueOf();
+    }
+
+    @Override
+    public Object clone() {
+	final OtpErlangMap newMap = (OtpErlangMap) super.clone();
+	newMap.values = values.clone();
+	return newMap;
+    }
+}
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpExternal.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpExternal.java
index 45a82d6c94..fa0fe18e95 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpExternal.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpExternal.java
@@ -85,6 +85,9 @@ public class OtpExternal {
     /** The tag used for new style references */
     public static final int newRefTag = 114;
 
+    /** The tag used for maps */
+    public static final int mapTag = 116;
+
     /** The tag used for old Funs */
     public static final int funTag = 117;
 
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpInputStream.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpInputStream.java
index 9dc1728346..0d1342d796 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpInputStream.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpInputStream.java
@@ -1202,6 +1202,9 @@ public class OtpInputStream extends ByteArrayInputStream {
 	case OtpExternal.newRefTag:
 	    return new OtpErlangRef(this);
 
+        case OtpExternal.mapTag:
+            return new OtpErlangMap(this);
+
 	case OtpExternal.portTag:
 	    return new OtpErlangPort(this);
 
@@ -1244,4 +1247,21 @@ public class OtpInputStream extends ByteArrayInputStream {
 	    throw new OtpErlangDecodeException("Uknown data type: " + tag);
 	}
     }
+
+    public int read_map_head() throws OtpErlangDecodeException {
+        int arity = 0;
+        final int tag = read1skip_version();
+
+        // decode the map header and get arity
+        switch (tag) {
+        case OtpExternal.mapTag:
+            arity = read4BE();
+            break;
+
+        default:
+            throw new OtpErlangDecodeException("Not valid map tag: " + tag);
+        }
+
+        return arity;
+    }
 }
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
index 78f47aa32f..a78423db44 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
@@ -974,4 +974,9 @@ public class OtpOutputStream extends ByteArrayOutputStream {
 	write_atom(function);
 	write_long(arity);
     }
+
+    public void write_map_head(final int arity) {
+        write1(OtpExternal.mapTag);
+        write4BE(arity);
+    }
 }
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/java_files b/lib/jinterface/java_src/com/ericsson/otp/erlang/java_files
index 1390542194..62fa7f990e 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/java_files
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/java_files
@@ -74,6 +74,7 @@ ERL = \
 	OtpErlangShort\
 	OtpErlangString\
 	OtpErlangTuple \
+	OtpErlangMap \
 	OtpErlangUInt \
 	OtpErlangUShort